physicsworld--2020-11-09--Nobel laureates claim European Commission set to slash photonics budget by 30% - Physics World

Three Nobel-prize-winning physicists claim that the European Commission is planning to “ drastically cut ” funding for photonics in its next €100bn research and innovation programme .
Gérard Mourou , Stefan Hell and Theodore Hänsch have warned in an open letter to the commission that such a move will be disastrous for Europe ’ s technological goals and damage its competitiveness .
The three researchers ’ target is Photonics21 – a public–private partnership supported by the European Commission to bring optical researchers and industries together .
It had requested a minimum budget of €1.4bn in the Horizon Europe programme , @ @ @ @ @ @ @ But in their letter , the laureates claim to have learned from “ informed sources in Brussels ” that the commission will instead propose around €500m .
This figure , which is barely 35 % of the requested budget , would represent a 30 % cut on the €700m that the photonics sector received from the EU between 2014 and 2020 .
The laureates say that the amount of money proposed by the commission for photonics is “ not consistent ” with planned support for other key digital technologies , such as artificial @ @ @ @ @ @ @ to 2020 had a budget of €2.5bn .
“ Europe needs to strengthen , not weaken , its industry and innovation capacity in photonics , ” the laureates write , warning that without photonics technologies , Europe will not be fit for developments in quantum computing or to allow “ full digital sovereignty ” .
They also say that the “ risk of losing another key digital technology to other regions of the world is serious ” .
The laureates point out that the European Commission ’ s recent industrial strategy identified photonics @ @ @ @ @ @ @ ’ s industrial future .
The European Investment Bank has also identified photonics as a key technology that will provide secure , sovereign and resilient digital infrastructure .
This support , they argue , underlines how essential photonics is to four EU objectives : digital transformation of industry ; the European Green deal ; digital sovereignty and resilient digital infrastructure ; and strengthening strategic value chains across key sectors .
According to Photonics21 , the European photonics market could triple in value to more than €200bn by 2030 , while some 700 000 @ @ @ @ @ @ @ sector in Europe by 2030 .
In their letter , the laureates call for photonics funding to match Europe ’ s digital ambitions .
“ Genuine advancements in photonics are truly essential for powering the future European digital economy , ” they write .
“ They are often driven by fundamental research…We therefore kindly request you to reconsider any cuts to the photonics partnership given its vital cross-sectional importance for Europe.
” This is not the first time the photonics community has raised concerns about funding and the European Commission ’ s view @ @ @ @ @ @ @ Mourou , Hell and Hänsch wrote another open letter to the Commission calling for it to recognize photonics as a vital research area and add it as the “ tenth technology priority ” in the upcoming Horizon Europe programme .
At the end of 2018 the European Photonics Industry Consortium released a statement making a similar request and criticizing the Commission ’ s proposed budget .

Nobel laureates Gérard Mourou, Stefan Hell and Theodore Hänsch have warned in an open letter to the European Commission that cuts to photonics would be disastrous for Europe's technological goals and damage its competitiveness. (Courtesy: Shutterstock/seahorsetwo)
Three Nobel-prize-winning physicists claim that the European Commission is planning to “drastically cut” funding for photonics in its next €100bn research and innovation programme. Gérard Mourou, Stefan Hell and Theodore Hänsch have warned in an open letter to the commission that such a move will be disastrous for Europe’s technological goals and damage its competitiveness.
The three researchers’ target is Photonics21 – a public–private partnership supported by the European Commission to bring optical researchers and industries together. It had requested a minimum budget of €1.4bn in the Horizon Europe programme, which runs from 2021 to 2027. But in their letter, the laureates claim to have learned from “informed sources in Brussels” that the commission will instead propose around €500m.
This figure, which is barely 35% of the requested budget, would represent a 30% cut on the €700m that the photonics sector received from the EU between 2014 and 2020. The laureates say that the amount of money proposed by the commission for photonics is “not consistent” with planned support for other key digital technologies, such as artificial intelligence and microelectronics, which from 2014 to 2020 had a budget of €2.5bn.
“Europe needs to strengthen, not weaken, its industry and innovation capacity in photonics,” the laureates write, warning that without photonics technologies, Europe will not be fit for developments in quantum computing or to allow “full digital sovereignty”. They also say that the “risk of losing another key digital technology to other regions of the world is serious”.
The laureates point out that the European Commission’s recent industrial strategy identified photonics as a strategically important technology for Europe’s industrial future. The European Investment Bank has also identified photonics as a key technology that will provide secure, sovereign and resilient digital infrastructure.
This support, they argue, underlines how essential photonics is to four EU objectives: digital transformation of industry; the European Green deal; digital sovereignty and resilient digital infrastructure; and strengthening strategic value chains across key sectors. According to Photonics21, the European photonics market could triple in value to more than €200bn by 2030, while some 700,000 new jobs could be created in the sector in Europe by 2030.
In their letter, the laureates call for photonics funding to match Europe’s digital ambitions. “Genuine advancements in photonics are truly essential for powering the future European digital economy,” they write. “They are often driven by fundamental research…We therefore kindly request you to reconsider any cuts to the photonics partnership given its vital cross-sectional importance for Europe.”
This is not the first time the photonics community has raised concerns about funding and the European Commission’s view of the sector. Early last year Mourou, Hell and Hänsch wrote another open letter to the Commission calling for it to recognize photonics as a vital research area and add it as the “tenth technology priority” in the upcoming Horizon Europe programme. At the end of 2018 the European Photonics Industry Consortium released a statement making a similar request and criticizing the Commission’s proposed budget.


physicsworld--2020-11-10--Ferroelectricity: 100 years on - Physics World

Great discoveries are sometimes made without anyone realizing quite how important they will be .
C V Raman , for example , won the Nobel Prize for Physics in 1930 for discovering that light can change energy when it scatters , yet Raman spectroscopy did not become a valuable research tool until well after the laser was invented in 1960 .
Similarly , few could have imagined that Paul Dirac ’ s far-fetched yet bold proposal of antiparticles – for which he won the 1933 Nobel prize – would lead to positron emission tomography half a century later .
But @ @ @ @ @ @ @ important – discovery that also went largely unrecognized at the time .
It was made 100 years ago in 1920 by Joseph Valasek ( 1897–1993 ) , who was then a graduate student working under the supervision of William Swann at the University of Minnesota , Minneapolis , US .
Seeking to develop a seismograph to measure the vibrations from earthquakes , Valasek wondered if this could be done with piezoelectric crystals , which create an electric signal when squeezed .
The most readily available piezoelectric he had at hand was a single-crystalline @ @ @ @ @ @ @ by Pierre Seignette , a pharmacist from the French seaport of La Rochelle .
Extracted from wine , it became known as Rochelle salt or Seignette salt and has the chemical formula potassium sodium tartrate tetrahydrate ( KNaC H O ·4H O ) .
When Valasek placed a sample of this material in an electric field , E , he noticed that its resulting electric polarization , P , did something unusual .
As he turned up the field , the polarization increased , with the graph of P versus E following an @ @ @ @ @ @ @ field was lowered again , the polarization was always higher than before albeit following the same kind of curve .
In other words , the precise value of the polarization depended on whether the field was rising or falling : it was showing hysteresis ( figure 1 ) .
So unusual was this observation that Swann presented it at the April 1920 meeting of the American Physical Society in Gaithersburg , Maryland , in a paper entitled “ Piezoelectric and allied phenomena in Rochelle salt ” .
( As a lowly PhD student @ @ @ @ @ @ @ meeting . )
Swann and Valasek did not know what caused the hysteresis , but there were parallels with a discovery that had been made three decades earlier by the Scottish physicist James Alfred Ewing .
He had seen a similar kind of behaviour in certain ferromagnets , noticing that the magnetic moment depends on how the magnetic field has changed .
Valasek ’ s discovery therefore pointed to an entirely new class of materials , in which the electric dipole moment – and hence the polarization – depends on how the electric @ @ @ @ @ @ @ ferroelectrics ” , these materials have some amazing applications in modern life ( see “ Applications of ferroelectrics : five of the best ” ) .
However , neither Swann nor Valasek had heard of the term , which had been coined in 1912 by Erwin Schrödinger after predicting that certain liquids can spontaneously polarize when they solidify .
What ’ s more , Valasek ’ s discovery went largely unnoticed .
Despite him writing four papers about his observations in Physical Review between 1921 and 1924 with a further note in Science @ @ @ @ @ @ @ to establish the theoretical basis for this phenomenon throughout the entire 1920s .
Most physicists , it seems , were more interested in quantum physics and other fundamental phenomena like Bragg diffraction and Raman spectroscopy .
Indeed , it was not until the late 1930s that anyone actually used the word “ ferroelectricity ” again in the literature .
Research only really took off after the future Nobel-prize-winning physicist Vitaly Ginzburg wrote a classic paper on the subject in 1946 , though even he called it the “ Seignettoelectric ” effect given that @ @ @ @ @ @ @ salt .
The field was also boosted by the discovery during the Second World War of another ferroelectric material : barium titanate ( BaTiO ) .
Unlike Rochelle salt , it is insoluble in water , chemically stable at room temperature , and has much better electrical and mechanical properties .
Barium titanate was therefore a perfect material for high-energy-density capacitors , although it was only after the war that researchers realized it was ferroelectric with a tell-tale hysteresis in its electrical properties .
Theorists now began to develop a proper understanding of @ @ @ @ @ @ @ experimentalists who started carrying out careful crystallographic analyses of the structure of these materials .
By the end of 1950s , several hundred different oxide-based ferroelectric materials – belonging to about 30 different structural families – had been discovered , with physicists testing their electrical properties and weighing up their potential for novel device applications .
One consequence of this systematic study of ferroelectrics came in 1968 when researchers such as Keitsiro Aizu from the Hitachi Central Research Laboratory in Tokyo , Japan , predicted that there could be a similar hysteresis-like relationship @ @ @ @ @ @ @ and its applied stress .
Dubbed “ ferroelastics ” , some of these materials are unusual in that if you cool them below a specific temperature and then mechanically distort them , they ’ ll recover their original shape if you heat them back up again .
These ferroelastics , in other words , “ remember ” their original physical and geometric shape .
They include “ shape-memory alloys ” such as nickel-titanium , which is widely used for actuating and positioning devices , while others are used in everything from electric cables @ @ @ @ @ @ @ frames .
Ferroelastics are even used in space to form antennas and other gadgets that can be folded up and then unfurled when heated up .
By the late 1960s , physicists therefore knew of three families of materials that all showed hysteresis : ferroelectrics , ferromagnets and ferroelastics .
What they all have in common is that neighbouring crystalline domains have a particular property “ pointing ” in opposite directions ( electric dipole for ferroelectrics , magnetism for ferromagnets , and strain for ferroelastics ) that can be “ switched ” with @ @ @ @ @ @ @ in the same direction .
Indeed , Ginzburg – and another future Nobel laureate , Lev Landau – were able to explain the behaviour of all three types by a single , simple , phenomenological theory .
Some scientists even started grouping the materials under the common banner of “ ferroics ” – a name that stuck in the literature despite many of the substances not actually containing any iron .
Indeed , in the 1970s a fourth family of ferroic materials , known as “ ferrotoroidics ” , was also discovered , @ @ @ @ @ @ @ field ( the cross product of the electric and magnetic field ) .
Including materials such as lithium cobalt phosphate ( LiCo ( PO ) ) they have magnetic vortices in neighbouring domains that can be made to line up .
And if that was not enough , researchers have also found materials that combine more than one ferroic property either in a single phase or as a composite structure .
Known as “ multiferroics ” , they include “ magnetoelectric ” materials in which the magnetization can be controlled by an electric @ @ @ @ @ @ @ by a magnetic field ( something that Pierre Curie had suggested as far back as 1894 ) .
Such materials can , for example , measure the picotesla-sized magnetic fields from human neurons at room temperature .
What ’ s most interesting about ferroelectrics is that such materials are also piezoelectric ( generating electricity when stressed ) and pyroelectric ( generating electricity when subject to a variation in temperature ) .
These unique properties have led to ferroelectrics being used in many applications from high-energy-density capacitors and night-vision devices to ultrasound medical equipment @ @ @ @ @ @ @ and actuators and translators .
You ’ ll even find ferroelectrics in burglar alarms , lighters , and heart-rate and blood-pressure monitors .
A century after the discovery of ferroelectricity , what started as a niche field of research has grown enormously , with more than 20,000 research papers published on the topic to date , driven by its myriad of applications from the nano- to the macroscopic scale .
It has even expanded into biology , with ferroelectric behaviour found to occur , for example , in amino acids and in the @ @ @ @ @ @ @ pigs .
Ferroelectrics could even be used to make sensors that can replicate many human “ multifunctional sensory systems ” .
Other interesting developments include exotic materials such as “ relaxors ” ( in which the dielectric response depends on the frequency of the applied field ) and “ quantum paraelectricity ” ( in which quantum fluctuations suppress the onset of ferroelectric order ) .
Researchers have also started to study 2D ferroelectrics , with atom-by-atom deposition and first-principles calculations pointing to new kinds of nanoscale devices and sensors that could be particularly @ @ @ @ @ @ @ After all , skin , hair , nails and many other biological tissues behave as piezoelectrics and ferroelectrics when exposed to an electric field , with piezoresponse-force microscopes already providing quantitative data on human biofunctionality .
Even fundamental physics has not been immune from the power of ferroelectrics , with researchers recently observing exotic topological defects called “ polar skyrmions ” and “ polar hopfions ” in ferroelectric materials for the first time .
What started out as an innocuous experimental observation by a graduate student a century ago will , we believe @ @ @ @ @ @ @ and life for another 100 years and beyond .
Applications of ferroelectrics : five of the best One big benefit of ferroelectric materials is that they have a very high dielectric constant , which means they can store lots of energy .
Most capacitors in high-energy-density applications , such as compact batteries , therefore contain ferroelectric materials .
And despite behaving as insulators with very high electrical resistance , ferroelectrics also played a key role in the discovery of a new class of materials with zero resistance .
Working at IBM ’ s @ @ @ @ @ @ @ the future Nobel laureate physicist Alex Müller was studying perovskites – a group of materials that includes ferroelectrics .
By tweaking the composition but maintaining their basic structure , he found that these materials carried current without resistance at about 40 K , while others found similar behaviour at liquid-nitrogen temperatures .
So for high-temperature superconductors , we can thank ferroelectrics .
Cameras that can “ see ” at night require materials that generate electric charge in response to variations in temperature .
Pyroelectrics , which generate a voltage when heated or cooled @ @ @ @ @ @ @ it is better to use ferroelectrics such as triglycine sulphate .
They have a much higher “ pyroelectric coefficient ” and can resolve temperature differences as small as 0.01 K. Infrared radiation from , say , a human body can be focused onto arrays of ferroelectric materials , which absorb the light and turn it into a voltage that can be used to create an image corresponding to the person ’ s temperature profile .
Such cameras are also used in medicine , security and night vision .
Zoologists have even used night-vision @ @ @ @ @ @ @ thought were extinct , including wild dogs in New Guinea .
All ferroelectric materials are piezoelectric , which means they generate an electrical voltage when put under pressure by an object .
The voltage can then be used to create an image of the object .
However , the pressure doesn ’ t have to be through direct physical contact : it can also come from sound waves reflected off an object that itself is under stress .
Ferroelectrics are therefore widely used in medicine for imaging unborn babies to check how they @ @ @ @ @ @ @ ’ s womb .
A similar principle lies behind the hydrophone : a device that can collect sound waves bouncing off underwater objects , such as schools of fish .
Ferroelectrics have also been used to map the topography of the ocean floor – such as in 2014 when they were used to locate Malaysian Airlines flight MH370 , which disappeared somewhere in the southern Indian Ocean on a flight from Kuala Lumpur to Beijing .
Given that all ferroelectrics are piezoelectric , if you apply an electric field , the material will @ @ @ @ @ @ @ directions as determined by its basic crystal structure .
The change in size can be barely a few picometres per volt – but that can still be invaluable .
Ferroelectrics such as lead zirconium titanate , for example , are used in atomic force microscopes to see individual atoms in materials and also in scanning tunnelling microscopes , for which Gerd Binnig and Heinrich Rohrer won the 1986 Nobel Prize for Physics .
Similar materials can also be found in piezoforce microscopes and magnetoforce microscopes .
Indeed , another ferroelectric – lead magnesium @ @ @ @ @ @ @ device that NASA used in 1991 to correct flaws in the mirror on the Hubble Space Telescope .
Previously washed-out images , such as of the core of galaxy M100 , were now much clearer ( compare above left and right ) .
Ferroelectric materials can generate electricity under the influence of an input thrust , meaning that some – such as lead zirconium titanate embedded in a polymer – could be used to harvest the energy from cars and lorries that is otherwise lost as heat or noise .
The power that @ @ @ @ @ @ @ currently relatively small – typically a few milliwatts – based as it is on sheets of polyvinylidene difluoride ( PVDF ) and their polymer composites .
But if we can find cheap ways to scale up the production of devices , we could be on to a winner .
Another promising application of energy-harvesting devices is in medicine and biology , where only very small energies are involved .
They could be a boon for patients who have been fitted with battery-powered mechanical pacemakers to keep their hearts pumping .
If the batteries @ @ @ @ @ @ @ replace them is for a surgeon to operate on the patient .
But if the batteries could be recharged by the voltage generated in a ferroelectric material directly from the thrust of the heartbeat , such operations would be a thing of the past .

Physics World. Members of the Institute of Physics can enjoy the full issue Taken from the November 2020 issue of. Members of the Institute of Physics can enjoy the full issue via the Physics World app
When a PhD student called Joseph Valasek discovered ferroelectricity exactly 100 years ago, few people realized the enormous impact it would have on science and technology. Amar S Bhalla and Avadh Saxena pick their favourite applications of this fundamental physics phenomenon
Century celebration Light shining through the faces of a crystal of Rochelle salt – the material in which ferroelectricity was discovered in 1920. (Courtesy: iStock/Grover Schraye)
Great discoveries are sometimes made without anyone realizing quite how important they will be. C V Raman, for example, won the Nobel Prize for Physics in 1930 for discovering that light can change energy when it scatters, yet Raman spectroscopy did not become a valuable research tool until well after the laser was invented in 1960. Similarly, few could have imagined that Paul Dirac’s far-fetched yet bold proposal of antiparticles – for which he won the 1933 Nobel prize – would lead to positron emission tomography half a century later.
But there is a lesser known – yet important – discovery that also went largely unrecognized at the time. It was made 100 years ago in 1920 by Joseph Valasek (1897–1993), who was then a graduate student working under the supervision of William Swann at the University of Minnesota, Minneapolis, US. Seeking to develop a seismograph to measure the vibrations from earthquakes, Valasek wondered if this could be done with piezoelectric crystals, which create an electric signal when squeezed.
The most readily available piezoelectric he had at hand was a single-crystalline substance first synthesized in the 17th century by Pierre Seignette, a pharmacist from the French seaport of La Rochelle. Extracted from wine, it became known as Rochelle salt or Seignette salt and has the chemical formula potassium sodium tartrate tetrahydrate (KNaC 4 H 4 O 6 ·4H 2 O). When Valasek placed a sample of this material in an electric field, E, he noticed that its resulting electric polarization, P, did something unusual.
As he turned up the field, the polarization increased, with the graph of P versus E following an S-shaped curve. However, when the field was lowered again, the polarization was always higher than before albeit following the same kind of curve. In other words, the precise value of the polarization depended on whether the field was rising or falling: it was showing hysteresis (figure 1). So unusual was this observation that Swann presented it at the April 1920 meeting of the American Physical Society in Gaithersburg, Maryland, in a paper entitled “Piezoelectric and allied phenomena in Rochelle salt”. (As a lowly PhD student, Valasek did not even attend the meeting.)
Swann and Valasek did not know what caused the hysteresis, but there were parallels with a discovery that had been made three decades earlier by the Scottish physicist James Alfred Ewing. He had seen a similar kind of behaviour in certain ferromagnets, noticing that the magnetic moment depends on how the magnetic field has changed. Valasek’s discovery therefore pointed to an entirely new class of materials, in which the electric dipole moment – and hence the polarization – depends on how the electric field has changed.
1 The discovery of ferroelectricity (a) Joseph Valasek (1897–1993) discovered ferroelectricity as a PhD student in 1920 when measuring the polarization of potassium sodium tartrate tetrahydrate as a function of the applied electric field. (Courtesy: AIP Emilio Segrè Visual Archives, Physics Today Collection) (b) As Valasek found, the polarization, P, of a ferroelectric material increases following an S-shaped curve when the electric field, E, is increased. But when E is lowered again, the value of P is higher than before. This hysteresis is also seen in ferromagnetics (which show a hysteresis in the magnetization, M, versus applied magnetic field H) and in ferroelastics (which show a hysteresis in the strain, ε, versus applied stress σ). All of these materials have a finite value of P, M or ε at zero field, with two distinct orientation states (indicated by the blue arrows).
Steady success
Now called “ferroelectrics”, these materials have some amazing applications in modern life (see “Applications of ferroelectrics: five of the best”). However, neither Swann nor Valasek had heard of the term, which had been coined in 1912 by Erwin Schrödinger after predicting that certain liquids can spontaneously polarize when they solidify. What’s more, Valasek’s discovery went largely unnoticed. Despite him writing four papers about his observations in Physical Review between 1921 and 1924 with a further note in Science in 1927, no attempts were made to establish the theoretical basis for this phenomenon throughout the entire 1920s.
Most physicists, it seems, were more interested in quantum physics and other fundamental phenomena like Bragg diffraction and Raman spectroscopy. Indeed, it was not until the late 1930s that anyone actually used the word “ferroelectricity” again in the literature. Research only really took off after the future Nobel-prize-winning physicist Vitaly Ginzburg wrote a classic paper on the subject in 1946, though even he called it the “Seignettoelectric” effect given that it had been first observed in Seignette salt.
The field was also boosted by the discovery during the Second World War of another ferroelectric material: barium titanate (BaTiO 3 ). Unlike Rochelle salt, it is insoluble in water, chemically stable at room temperature, and has much better electrical and mechanical properties. Barium titanate was therefore a perfect material for high-energy-density capacitors, although it was only after the war that researchers realized it was ferroelectric with a tell-tale hysteresis in its electrical properties.
Theorists now began to develop a proper understanding of the behaviour of ferroelectrics, helped by experimentalists who started carrying out careful crystallographic analyses of the structure of these materials. By the end of 1950s, several hundred different oxide-based ferroelectric materials – belonging to about 30 different structural families – had been discovered, with physicists testing their electrical properties and weighing up their potential for novel device applications.
One consequence of this systematic study of ferroelectrics came in 1968 when researchers such as Keitsiro Aizu from the Hitachi Central Research Laboratory in Tokyo, Japan, predicted that there could be a similar hysteresis-like relationship between a material’s elastic strain and its applied stress. Dubbed “ferroelastics”, some of these materials are unusual in that if you cool them below a specific temperature and then mechanically distort them, they’ll recover their original shape if you heat them back up again.
These ferroelastics, in other words, “remember” their original physical and geometric shape. They include “shape-memory alloys” such as nickel-titanium, which is widely used for actuating and positioning devices, while others are used in everything from electric cables on the ocean floor to bendable spectacle frames. Ferroelastics are even used in space to form antennas and other gadgets that can be folded up and then unfurled when heated up.
Meet the family
By the late 1960s, physicists therefore knew of three families of materials that all showed hysteresis: ferroelectrics, ferromagnets and ferroelastics. What they all have in common is that neighbouring crystalline domains have a particular property “pointing” in opposite directions (electric dipole for ferroelectrics, magnetism for ferromagnets, and strain for ferroelastics) that can be “switched” with an external field so they all point in the same direction. Indeed, Ginzburg – and another future Nobel laureate, Lev Landau – were able to explain the behaviour of all three types by a single, simple, phenomenological theory.
Some scientists even started grouping the materials under the common banner of “ferroics” – a name that stuck in the literature despite many of the substances not actually containing any iron. Indeed, in the 1970s a fourth family of ferroic materials, known as “ferrotoroidics”, was also discovered, which have a hysteresis in the toroidic field (the cross product of the electric and magnetic field). Including materials such as lithium cobalt phosphate (LiCo(PO 4 ) 3 ) they have magnetic vortices in neighbouring domains that can be made to line up.
And if that was not enough, researchers have also found materials that combine more than one ferroic property either in a single phase or as a composite structure. Known as “multiferroics”, they include “magnetoelectric” materials in which the magnetization can be controlled by an electric field and the polarization can be manipulated by a magnetic field (something that Pierre Curie had suggested as far back as 1894). Such materials can, for example, measure the picotesla-sized magnetic fields from human neurons at room temperature.
What’s most interesting about ferroelectrics is that such materials are also piezoelectric (generating electricity when stressed) and pyroelectric (generating electricity when subject to a variation in temperature). These unique properties have led to ferroelectrics being used in many applications from high-energy-density capacitors and night-vision devices to ultrasound medical equipment, smart technologies for energy harvesting, and actuators and translators. You’ll even find ferroelectrics in burglar alarms, lighters, and heart-rate and blood-pressure monitors.
The future is ferroelectric
A century after the discovery of ferroelectricity, what started as a niche field of research has grown enormously, with more than 20,000 research papers published on the topic to date, driven by its myriad of applications from the nano- to the macroscopic scale. It has even expanded into biology, with ferroelectric behaviour found to occur, for example, in amino acids and in the wall of the aortic blood vessels in pigs. Ferroelectrics could even be used to make sensors that can replicate many human “multifunctional sensory systems”.
Other interesting developments include exotic materials such as “relaxors” (in which the dielectric response depends on the frequency of the applied field) and “quantum paraelectricity” (in which quantum fluctuations suppress the onset of ferroelectric order). Researchers have also started to study 2D ferroelectrics, with atom-by-atom deposition and first-principles calculations pointing to new kinds of nanoscale devices and sensors that could be particularly useful for studying the human body. After all, skin, hair, nails and many other biological tissues behave as piezoelectrics and ferroelectrics when exposed to an electric field, with piezoresponse-force microscopes already providing quantitative data on human biofunctionality.
Even fundamental physics has not been immune from the power of ferroelectrics, with researchers recently observing exotic topological defects called “polar skyrmions” and “polar hopfions” in ferroelectric materials for the first time. What started out as an innocuous experimental observation by a graduate student a century ago will, we believe, continue to benefit science, technology and life for another 100 years and beyond.
Applications of ferroelectrics: five of the best High-energy capacitors and efficient energy storage devices (Courtesy: Ella Maru Studio/Science Photo Library) One big benefit of ferroelectric materials is that they have a very high dielectric constant, which means they can store lots of energy. Most capacitors in high-energy-density applications, such as compact batteries, therefore contain ferroelectric materials. And despite behaving as insulators with very high electrical resistance, ferroelectrics also played a key role in the discovery of a new class of materials with zero resistance. Working at IBM’s Zurich research lab in the mid-1980s, the future Nobel laureate physicist Alex Müller was studying perovskites – a group of materials that includes ferroelectrics. By tweaking the composition but maintaining their basic structure, he found that these materials carried current without resistance at about 40 K, while others found similar behaviour at liquid-nitrogen temperatures. So for high-temperature superconductors, we can thank ferroelectrics. Night-vision technology (Courtesy: iStock/Pixel-Productions) Cameras that can “see” at night require materials that generate electric charge in response to variations in temperature. Pyroelectrics, which generate a voltage when heated or cooled, can do the job, but it is better to use ferroelectrics such as triglycine sulphate. They have a much higher “pyroelectric coefficient” and can resolve temperature differences as small as 0.01 K. Infrared radiation from, say, a human body can be focused onto arrays of ferroelectric materials, which absorb the light and turn it into a voltage that can be used to create an image corresponding to the person’s temperature profile. Such cameras are also used in medicine, security and night vision. Zoologists have even used night-vision devices to see animals that they previously thought were extinct, including wild dogs in New Guinea. Medical ultrasound and underwater acoustics (Courtesy: iStock/monkeybusinessimages) All ferroelectric materials are piezoelectric, which means they generate an electrical voltage when put under pressure by an object. The voltage can then be used to create an image of the object. However, the pressure doesn’t have to be through direct physical contact: it can also come from sound waves reflected off an object that itself is under stress. Ferroelectrics are therefore widely used in medicine for imaging unborn babies to check how they are growing and developing inside the mother’s womb. A similar principle lies behind the hydrophone: a device that can collect sound waves bouncing off underwater objects, such as schools of fish. Ferroelectrics have also been used to map the topography of the ocean floor – such as in 2014 when they were used to locate Malaysian Airlines flight MH370, which disappeared somewhere in the southern Indian Ocean on a flight from Kuala Lumpur to Beijing. Actuators and translators (Courtesy: NASA) Given that all ferroelectrics are piezoelectric, if you apply an electric field, the material will change dimension along one or more permitted directions as determined by its basic crystal structure. The change in size can be barely a few picometres per volt – but that can still be invaluable. Ferroelectrics such as lead zirconium titanate, for example, are used in atomic force microscopes to see individual atoms in materials and also in scanning tunnelling microscopes, for which Gerd Binnig and Heinrich Rohrer won the 1986 Nobel Prize for Physics. Similar materials can also be found in piezoforce microscopes and magnetoforce microscopes. Indeed, another ferroelectric – lead magnesium niobate/lead titanate – was part of the device that NASA used in 1991 to correct flaws in the mirror on the Hubble Space Telescope. Previously washed-out images, such as of the core of galaxy M100, were now much clearer (compare above left and right). Energy harvesting (Courtesy: iStock/RistoArnaudov) Ferroelectric materials can generate electricity under the influence of an input thrust, meaning that some – such as lead zirconium titanate embedded in a polymer – could be used to harvest the energy from cars and lorries that is otherwise lost as heat or noise. The power that can be generated from such devices is currently relatively small – typically a few milliwatts – based as it is on sheets of polyvinylidene difluoride (PVDF) and their polymer composites. But if we can find cheap ways to scale up the production of devices, we could be on to a winner. Another promising application of energy-harvesting devices is in medicine and biology, where only very small energies are involved. They could be a boon for patients who have been fitted with battery-powered mechanical pacemakers to keep their hearts pumping. If the batteries run out, the only way to replace them is for a surgeon to operate on the patient. But if the batteries could be recharged by the voltage generated in a ferroelectric material directly from the thrust of the heartbeat, such operations would be a thing of the past.


physicsworld--2020-11-10--Mid-IR spectrometer provides non-invasive skin cancer detection - Physics World

Researchers in Israel have developed and tested a fibre-optic evanescent wave spectroscopy ( FEWS ) system that can non-invasively identify and characterize skin cancers .
They successfully identified cancerous lesions on patients ’ skin by touching the suspicious regions for 30 s with an optical fibre connected to a mid-infrared ( IR ) spectrometer .
An estimated 300,000 cases of melanoma and over one million cases of non-melanoma skin cancer were diagnosed in 2018 , according to the World Cancer Research Fund and the American Institute for Cancer Research .
Suspicious lesions are usually identified by dermatologists using a dermascope @ @ @ @ @ @ @ are subsequently diagnosed based on pathological analysis of biopsied tissue .
This process , however , is invasive , costly , time-consuming and dependent upon the skill of the physician .
To address these shortfalls , Abraham Katzir of Tel Aviv University and co-researchers are working to create an accurate , affordable clinical system that can identify skin cancers in near-real-time and could be used by dermatologists for reliable screening of suspicious lesions .
Writing in Medical Physics , the researchers describe their achievements to date .
The FEWS system is based on @ @ @ @ @ @ @ U-shaped , mid-IR transmitting AgCIBr fibre .
The fibre , developed by Tel Aviv University ’ s applied physics group , is flexible , non-toxic , non-hygroscopic and highly transparent in the mid-IR .
The system operates in the 3– 30 μm spectral range , to measure the mid-IR absorption spectra of tissues .
To record an absorption spectrum , the centre of the U-shaped fibre is simply brought into contact with the skin .
The researchers aimed to use the FEWS system to detect and identify three skin cancers : melanoma , @ @ @ @ @ @ @ squamous cell carcinoma ( SCC ) .
For 90 patients in the dermatology department of the Tel Aviv Sourasky Medical Center , they measured the absorption spectra of each suspicious skin lesion and the surrounding healthy tissue , a process that took about 30 s per measurement .
The absorption spectra of the measured samples exhibited several peaks in the mid-IR region .
Unique peaks at similar wavenumbers and within specific spectral ranges , were easily identified by the naked eye as signatures of melanoma , BCC or SCC .
The team created @ @ @ @ @ @ @ melanoma , BCC , SCC and healthy tissue , based on differences in the absorption spectra .
These spectra corresponded with the pathology of the patients ’ tissue biopsies , which included five melanomas , seven BCCs and three SCCs .
In a recent refinement of their diagnostic method , the researchers developed an algorithm to analyse the spectra and deliver the results .
For melanoma , this algorithm achieved 100 % sensitivity , specificity and accuracy .
One potential obstacle with this approach is that mid-IR radiation only penetrates only a few @ @ @ @ @ @ @ upper layer of the skin .
The researchers suggest that this thin layer would include cells that have migrated upwards from deeper malignant lesions .
“ This study confirmed that the melanoma-affected cells migrate from the layers of the skin to the thin top layer , ” explains Katzir .
“ We were able to use mid-IR spectroscopy on this very thin layer of skin to detect these cells , without breaking the skin , and from that to determine the type of cancer present .
The differences among the cancer types were @ @ @ @ @ @ @ comparison of the spectra .
This non-invasive ‘ spectroscopic pathology ’ may , in the future , replace the standard invasive biopsy.
” Katzir tells Physics World that the team is planning to conduct a larger number of experiments in a collaboration with the Sheba Medical Center , which has a large medical clinic dedicated to skin cancer .
“ Our main interest is to develop a system that will automatically diagnose lesions , independent of the skill of the physician , ” Katzir explains .
“ It will determine if the lesions @ @ @ @ @ @ @ are melanoma or less lethal cancers , all in real-time and in the clinic .
The dermatologist community and the medical authorities are looking for a method that will diagnose , with a success rate of more than 95 % , both malignant and benign skin lesions .
If we succeed , we will try to get an approval for the method and then we will be ready for commercialization.
” The next step will be to collect more data to improve the data analysis .
The system also needs to be refined @ @ @ @ @ @ @ commercial mid-IR spectrometer with a quantum cascade laser ( QCL ) -based system that will only cover the spectral range of interest , have higher intensity and be more compact .
They also plan to improve their software algorithms to better detect melanoma and other pathologies , and to generate these findings automatically .
“ We hope to develop a system that is small , lightweight , rugged , very easy to operate and , most importantly , inexpensive , ” says Katzir .
“ We want to reduce the cost to be @ @ @ @ @ @ @ ) , so that small clinics can afford to purchase it .
This system has the potential to make a sea change in the diagnosis of skin cancers and possibly other types of cancer .
This is our goal .
”

The sensor system is based on a spectrometer and a mid-IR transmitting fibre. When the exposed central part of the fibre (the U-shape) touches a skin lesion, the system measures its characteristic mid-IR absorption spectrum. (Courtesy: Abraham Katzir, Applied Physics Group, Tel Aviv University)
Researchers in Israel have developed and tested a fibre-optic evanescent wave spectroscopy (FEWS) system that can non-invasively identify and characterize skin cancers. They successfully identified cancerous lesions on patients’ skin by touching the suspicious regions for 30 s with an optical fibre connected to a mid-infrared (IR) spectrometer.
An estimated 300,000 cases of melanoma and more than one million cases of non-melanoma skin cancer were diagnosed in 2018, according to the World Cancer Research Fund and the American Institute for Cancer Research. Suspicious lesions are usually identified by dermatologists using a dermascope, a handheld optical magnifier, and are subsequently diagnosed based on pathological analysis of biopsied tissue. This process, however, is invasive, costly, time-consuming and dependent upon the skill of the physician.
To address these shortfalls, Abraham Katzir of Tel Aviv University and co-researchers are working to create an accurate, affordable clinical system that can identify skin cancers in near-real-time and could be used by dermatologists for reliable screening of suspicious lesions. Writing in Medical Physics, the researchers describe their achievements to date.
The FEWS system is based on a mid-IR spectrometer and a long, U-shaped, mid-IR transmitting AgCIBr fibre. The fibre, developed by Tel Aviv University’s applied physics group, is flexible, non-toxic, non-hygroscopic and highly transparent in the mid-IR. The system operates in the 3–30 μm spectral range, to measure the mid-IR absorption spectra of tissues. To record an absorption spectrum, the centre of the U-shaped fibre is simply brought into contact with the skin.
Patient studies
The researchers aimed to use the FEWS system to detect and identify three skin cancers: melanoma, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). For 90 patients in the dermatology department of the Tel Aviv Sourasky Medical Center, they measured the absorption spectra of each suspicious skin lesion and the surrounding healthy tissue, a process that took about 30 s per measurement.
The absorption spectra of the measured samples exhibited several peaks in the mid-IR region. Unique peaks at similar wavenumbers and within specific spectral ranges, were easily identified by the naked eye as signatures of melanoma, BCC or SCC. The team created “biochemical fingerprints” for samples of melanoma, BCC, SCC and healthy tissue, based on differences in the absorption spectra. These spectra corresponded with the pathology of the patients’ tissue biopsies, which included five melanomas, seven BCCs and three SCCs.
In a recent refinement of their diagnostic method, the researchers developed an algorithm to analyse the spectra and deliver the results. For melanoma, this algorithm achieved 100% sensitivity, specificity and accuracy.
One potential obstacle with this approach is that mid-IR radiation only penetrates only a few microns into the stratum corneum, the upper layer of the skin. The researchers suggest that this thin layer would include cells that have migrated upwards from deeper malignant lesions.
“This study confirmed that the melanoma-affected cells migrate from the layers of the skin to the thin top layer,” explains Katzir. “We were able to use mid-IR spectroscopy on this very thin layer of skin to detect these cells, without breaking the skin, and from that to determine the type of cancer present. The differences among the cancer types were large and were immediately noticed by simple comparison of the spectra. This non-invasive ‘spectroscopic pathology’ may, in the future, replace the standard invasive biopsy.”
Abraham Katzir.
Katzir tells Physics World that the team is planning to conduct a larger number of experiments in a collaboration with the Sheba Medical Center, which has a large medical clinic dedicated to skin cancer.
“Our main interest is to develop a system that will automatically diagnose lesions, independent of the skill of the physician,” Katzir explains. “It will determine if the lesions are cancerous, and conclude whether they are melanoma or less lethal cancers, all in real-time and in the clinic. The dermatologist community and the medical authorities are looking for a method that will diagnose, with a success rate of more than 95%, both malignant and benign skin lesions. If we succeed, we will try to get an approval for the method and then we will be ready for commercialization.”
The next step will be to collect more data to improve the data analysis. The system also needs to be refined. The researchers plan to replace the commercial mid-IR spectrometer with a quantum cascade laser (QCL)-based system that will only cover the spectral range of interest, have higher intensity and be more compact. They also plan to improve their software algorithms to better detect melanoma and other pathologies, and to generate these findings automatically.
“We hope to develop a system that is small, lightweight, rugged, very easy to operate and, most importantly, inexpensive,” says Katzir. “We want to reduce the cost to be less than £4000 (or $5000), so that small clinics can afford to purchase it. This system has the potential to make a sea change in the diagnosis of skin cancers and possibly other types of cancer. This is our goal.”


physicsworld--2020-11-10--Embracing a life of variables - Physics World

How did you first become interested in science , physics and engineering ?
I consider myself a formative engineer from an early age .
One of my first memories is disassembling the bathroom scales and then breaking down in tears because I couldn ’ t get them together again .
My dad helped me put it back together and that kicked off a childhood of making things , from model rockets and remote-control planes , to clocks and all sorts .
I learnt a lot from my dad , who was a mechanic by trade .
That led to an @ @ @ @ @ @ @ I found I had good skills in maths and physics , and I also joined the Air Cadets when I was a teenager .
Tell me a bit about your experience studying aerospace engineering at the University of Bristol , and how it compares to what you teach there today .
A lot of it is the same , but a lot has changed too .
When I was a student , the engineering course at Bristol was , and still is , maths and theory heavy .
But the bits that I @ @ @ @ @ @ @ the wing build .
We ’ ve expanded on that a lot in recent years , but when I did it , it was just a structural activity .
The other thing that jumps out in my memory is the flight test course .
Back in the day , we used an aircraft from another university where , I think , 12 of you at a time sat in these little seats with tiny windows and a little LCD screen in front of you .
You ’ re writing down data while this @ @ @ @ @ @ @ sky .
It had the highest utilization of sick bags of any flight that I ’ ve been on !
Nowadays , we do some work on the ground in simulators because we can then give every student consistent experiences , not limited by downtime or the weather , then take students up in gliders , in collaboration with our student gliding society .
It was a good course and I enjoyed it , but I found there ’ s nothing like four or five years of a deeply scientific engineering degree to @ @ @ @ @ @ @ .
So I pivoted at the end of my degree and went into teaching .
What specifically made you take a teaching training course after your degree , and become a physics teacher ?
I ’ d always enjoyed working with young people .
My family had fostered children for as long as I can remember .
My mum was a wonderful woman who ended up fostering more than 100 kids , most of whom had great outcomes .
I also liked doing youth work alongside my studies .
I took a break @ @ @ @ @ @ @ ended up working at a children ’ s camp , chucking kids off abseiling towers and things like that .
So I ’ d always thought about teaching .
But I don ’ t think I would have taken on another year of studying and student loans to do the classical option of a PGCE , or another degree .
I discovered this alternative teacher-training programme called Teach First , and the vocational approach really suited me .
The other advantage of that route is that it sells itself as a two-year course @ @ @ @ @ @ @ yourself into a teaching career , or as a skills-development opportunity .
I think going into general-science teaching as a physics specialist , and then going into physics teaching as an engineer , gave me a nice perspective on things .
Did you enjoy being a physics teacher ?
Physics has always been a passion of mine .
I think if I could go back , I might do my undergraduate degree in physics with astrophysics .
There ’ s a real shortage of physics specialist teachers in UK schools .
So being @ @ @ @ @ @ @ few , meant I had more teaching in my chosen specialism , and it was great .
I was teaching all the A-level stuff ( age 16–18 ) and leading on the curriculum-development side of things quite quickly too .
There are a lot of opportunities for progression if you ’ re in that niche and I absolutely loved it .
I really enjoyed combining my love of science with my desire to make a difference .
It wasn ’ t without its challenges – teaching can be an incredibly frustrating job , @ @ @ @ @ @ @ executive of Teach First at the time gave us a talk at the start of the course where he spoke about “ hills of happiness and valleys of despair ” .
I think my summary of teaching is that the highs are higher , and the lows are lower , than any other career I ’ ve experienced , but it ’ s just such a satisfying job .
What made you decide to go back to university after a few years of teaching , to do your PhD in aerospace dynamics and @ @ @ @ @ @ @ back to university as a selfish decision at the time .
I was doing well at school and I could see myself carrying on in that direction , but I had kept in touch with my Master ’ s project supervisor .
In 2010 he offered me a fully funded PhD , playing with giant robots and making them pretend to be aeroplanes .
I couldn ’ t turn that down .
So that brought me back to academia and to Bristol .
My intention was to do the PhD then go back @ @ @ @ @ @ @ in the West Country .
My PhD was funded for three and a half years .
But quite rapidly , alongside my studies , I carved a niche for myself in supporting students from diverse entry routes .
I took on the usual lab-demonstration stuff at the start of my PhD , but was also quickly given some sub-units to teach , and I tried some innovative stuff there .
Then the opportunity came up to support students coming from non-traditional , non-A-level entry routes , whom historically universities have not been great @ @ @ @ @ @ @ time for everything by going part-time on my PhD and part-time on the teaching side of things .
So actually it took me seven calendar years to finish my PhD .
Although pro rata , it was three and a half years to the day – exactly as intended .
You are now a programme director of aerospace engineering at Bristol – how did that come about ?
Once I finished my PhD , I became a full-time teaching fellow , and progressed at an accelerated rate through to senior lecturer today .
@ @ @ @ @ @ @ bit of a revolution as we ’ ve increased in student numbers and diversity .
I think there ’ s more of an onus on making sure that we ’ re tailoring our support to students .
I had the right skillset , and found myself in the right place at the right time .
I am now the programme director of our aerospace engineering undergraduate programmes , which is a very interesting place to be in this modern world of blended learning .
It ’ s weird looking back .
I think @ @ @ @ @ @ @ around so much would hold me back from progression on the traditional career route , in all of the areas of education that I ’ ve worked in , but actually it ’ s been a benefit .
I ’ ve made a name for myself because of the varied skillset that I have .
So they were all good decisions in hindsight .
What were the pitfalls , or stresses , of following this career random walk ?
I think that any successful story can be phrased in a way that looks @ @ @ @ @ @ @ would be surprised if that was the reality at the time .
Everyone has opportunities to direct what they want to do or push in a different direction .
I ’ ve spent a lot of time stressing about optimizing all the different trajectories in both my personal life and my career .
After a lot of soul-searching and a bit of coaching , I ’ ve come to the obvious realization that there are too many variables .
You can ’ t treat life like a control problem in engineering , so @ @ @ @ @ @ @ more as a social science .
I still find myself wondering : am I at a local or a global optimum ?
What are the other Steves in “ parallel universes ” doing ?
That ’ s a whole other Physics World article , right ?
But I do think about all of the branches I could have taken and where I might have gone .
I think feeling regret and loss for those doors that you ’ ve closed , or the branches that you allowed to wither , is folly and @ @ @ @ @ @ @ s not to say that you shouldn ’ t take sideways jumps – I ’ ve done several of those .
You ’ re not on rails , you ’ ve got the freedom to move whatever way you want to .
But it ’ s best to appreciate the path you do take and look to the future .
What are some barriers and challenges you have faced in your career , if any ?
I ’ ve definitely had a few challenges over the years .
First , I didn ’ @ @ @ @ @ @ @ for my first-choice university .
My options were to either go to my second choice , or defer for a year and go to my first .
So I took a forced gap year because I really wanted to go to Bristol .
This worked out well , as I had some great opportunities during that year , both working and then a little bit of travel .
Then during my undergrad studies , I was given a placement in parallel with my third year , with one of our close industrial partners @ @ @ @ @ @ @ been great , but the project was a defence-focused one .
I found myself feeling increasingly uncomfortable with that .
I like science for good but the thing that I was working on was uncomfortably close to the front-end of the defence industry .
I really struggled to motivate myself with that , which eventually cascaded into my wider studies .
Combined with a couple of other challenges that I was facing at the time , I ended up with a diagnosis of depression , some medication and me suspending my studies during @ @ @ @ @ @ @ , I wasn ’ t sure if I would return , but I kept the door open .
I decided to go for a hard reset , changed my scenery completely and worked at a children ’ s holiday camp for a summer , which was just what I needed .
I came back refreshed , completed my third and fourth years , and went into teaching .
It was a really difficult time , but after reaching my lowest point , I sought out the support that helped me get through it @ @ @ @ @ @ @ always try to encourage students and friends who are making tough decisions to think about the five-year test : in five years , is this going to be a major issue , or a minor blip ?
You don ’ t really know , but it ’ s often not as huge as it feels at the time , and sometimes that perspective can really help .
I still have crippling doubt at times and wonder what I ’ m doing , where it ’ s going and whether there ’ s a @ @ @ @ @ @ @ the signs to look for .
Again , to be a bit of an engineer , I call it preventative maintenance .
You need to know when you need to pay attention to that strange noise going on in the engine and have a look at it , take it apart , investigate and fix it if you can ; or when you can just live with it if you want to .
Being proactive about mental health , general stress levels , particularly in the current times , I think is really @ @ @ @ @ @ @ , take advantage of the academic and extracurricular opportunities that are offered , but be sensible and strategic about it .
Also , while it ’ s important to do as well as you can in your core course , have other parts of your life to complement that .
Find things that you ’ re passionate about – being interested makes you interesting .
I personally follow that even today – I spend a lot of time on my core work , but a passion of mine is science communication .
I @ @ @ @ @ @ @ Shed podcast , which regular Physics World readers may be familiar with .
I also love doing outreach and public engagement at festivals .
I cycle and go on outdoor adventures .
Great opportunities do come up fortuitously , if you have networks of people whom you can trust and rely on , but also you can share opportunities with , and then make connections through – there ’ s give and take .

Physics World. Members of the Institute of Physics can enjoy the full issue Taken from the November 2020 issue of. Members of the Institute of Physics can enjoy the full issue via the Physics World app
Steve Bullock is an engineer, physics teacher, science communicator and education consultant. Currently the programme director of undergraduate aerospace engineering at the University of Bristol, UK, he talks to Tushna Commissariat about a career of bold choices, sideways jumps and obstacles overcome
Relative motion Steve Bullock went from aerospace engineer to physics teacher to engineering lecturer. (Courtesy: Alex Sheppard/alexsheppard.co.uk)
How did you first become interested in science, physics and engineering?
I consider myself a formative engineer from an early age. One of my first memories is disassembling the bathroom scales and then breaking down in tears because I couldn’t get them together again. My dad helped me put it back together and that kicked off a childhood of making things, from model rockets and remote-control planes, to clocks and all sorts. I learnt a lot from my dad, who was a mechanic by trade. That led to an interest in the sciences at school. I found I had good skills in maths and physics, and I also joined the Air Cadets when I was a teenager.
Tell me a bit about your experience studying aerospace engineering at the University of Bristol, and how it compares to what you teach there today.
A lot of it is the same, but a lot has changed too. When I was a student, the engineering course at Bristol was, and still is, maths and theory heavy. But the bits that I really enjoyed were more practical, like the wing build. We’ve expanded on that a lot in recent years, but when I did it, it was just a structural activity.
The other thing that jumps out in my memory is the flight test course. Back in the day, we used an aircraft from another university where, I think, 12 of you at a time sat in these little seats with tiny windows and a little LCD screen in front of you. You’re writing down data while this aircraft is pitching and yawing about the sky. It had the highest utilization of sick bags of any flight that I’ve been on! Nowadays, we do some work on the ground in simulators because we can then give every student consistent experiences, not limited by downtime or the weather, then take students up in gliders, in collaboration with our student gliding society.
It was a good course and I enjoyed it, but I found there’s nothing like four or five years of a deeply scientific engineering degree to put you off it a little bit. So I pivoted at the end of my degree and went into teaching.
What specifically made you take a teaching training course after your degree, and become a physics teacher?
I’d always enjoyed working with young people. My family had fostered children for as long as I can remember. My mum was a wonderful woman who ended up fostering more than 100 kids, most of whom had great outcomes. I also liked doing youth work alongside my studies. I took a break from my studies at one point and ended up working at a children’s camp, chucking kids off abseiling towers and things like that. So I’d always thought about teaching. But I don’t think I would have taken on another year of studying and student loans to do the classical option of a PGCE, or another degree. I discovered this alternative teacher-training programme called Teach First, and the vocational approach really suited me. The other advantage of that route is that it sells itself as a two-year course that you can use either to launch yourself into a teaching career, or as a skills-development opportunity. I think going into general-science teaching as a physics specialist, and then going into physics teaching as an engineer, gave me a nice perspective on things.
Did you enjoy being a physics teacher?
Physics has always been a passion of mine. I think if I could go back, I might do my undergraduate degree in physics with astrophysics. There’s a real shortage of physics specialist teachers in UK schools. So being a physics teacher, one of the few, meant I had more teaching in my chosen specialism, and it was great. I was teaching all the A-level stuff (age 16–18) and leading on the curriculum-development side of things quite quickly too. There are a lot of opportunities for progression if you’re in that niche and I absolutely loved it.
I really enjoyed combining my love of science with my desire to make a difference. It wasn’t without its challenges – teaching can be an incredibly frustrating job, but also incredibly rewarding. The chief executive of Teach First at the time gave us a talk at the start of the course where he spoke about “hills of happiness and valleys of despair”. I think my summary of teaching is that the highs are higher, and the lows are lower, than any other career I’ve experienced, but it’s just such a satisfying job.
What made you decide to go back to university after a few years of teaching, to do your PhD in aerospace dynamics and control at Bristol?
I saw coming back to university as a selfish decision at the time. I was doing well at school and I could see myself carrying on in that direction, but I had kept in touch with my Master’s project supervisor. In 2010 he offered me a fully funded PhD, playing with giant robots and making them pretend to be aeroplanes. I couldn’t turn that down.
So that brought me back to academia and to Bristol. My intention was to do the PhD then go back to teaching, either in London or in the West Country. My PhD was funded for three and a half years. But quite rapidly, alongside my studies, I carved a niche for myself in supporting students from diverse entry routes. I took on the usual lab-demonstration stuff at the start of my PhD, but was also quickly given some sub-units to teach, and I tried some innovative stuff there. Then the opportunity came up to support students coming from non-traditional, non-A-level entry routes, whom historically universities have not been great at admitting or supporting.
I created time for everything by going part-time on my PhD and part-time on the teaching side of things. So actually it took me seven calendar years to finish my PhD. Although pro rata, it was three and a half years to the day – exactly as intended.
You are now a programme director of aerospace engineering at Bristol – how did that come about?
Once I finished my PhD, I became a full-time teaching fellow, and progressed at an accelerated rate through to senior lecturer today. Higher education has been going through a bit of a revolution as we’ve increased in student numbers and diversity. I think there’s more of an onus on making sure that we’re tailoring our support to students. I had the right skillset, and found myself in the right place at the right time. I am now the programme director of our aerospace engineering undergraduate programmes, which is a very interesting place to be in this modern world of blended learning.
It’s weird looking back. I think I was worried at times that jumping around so much would hold me back from progression on the traditional career route, in all of the areas of education that I’ve worked in, but actually it’s been a benefit. I’ve made a name for myself because of the varied skillset that I have. So they were all good decisions in hindsight.
What were the pitfalls, or stresses, of following this career random walk?
I think that any successful story can be phrased in a way that looks utterly sensible in hindsight, but I would be surprised if that was the reality at the time. Everyone has opportunities to direct what they want to do or push in a different direction. I’ve spent a lot of time stressing about optimizing all the different trajectories in both my personal life and my career. After a lot of soul-searching and a bit of coaching, I’ve come to the obvious realization that there are too many variables. You can’t treat life like a control problem in engineering, so you’ve got to treat it more as a social science.
You can’t treat life like a control problem in engineering
I still find myself wondering: am I at a local or a global optimum? What are the other Steves in “parallel universes” doing? That’s a whole other Physics World article, right? But I do think about all of the branches I could have taken and where I might have gone. I think feeling regret and loss for those doors that you’ve closed, or the branches that you allowed to wither, is folly and a path to disaster. That’s not to say that you shouldn’t take sideways jumps – I’ve done several of those. You’re not on rails, you’ve got the freedom to move whatever way you want to. But it’s best to appreciate the path you do take and look to the future.
What are some barriers and challenges you have faced in your career, if any?
I’ve definitely had a few challenges over the years. First, I didn’t quite get the grades I needed for my first-choice university. My options were to either go to my second choice, or defer for a year and go to my first. So I took a forced gap year because I really wanted to go to Bristol. This worked out well, as I had some great opportunities during that year, both working and then a little bit of travel.
Then during my undergrad studies, I was given a placement in parallel with my third year, with one of our close industrial partners on the programme. That should have been great, but the project was a defence-focused one. I found myself feeling increasingly uncomfortable with that. I like science for good but the thing that I was working on was uncomfortably close to the front-end of the defence industry. I really struggled to motivate myself with that, which eventually cascaded into my wider studies.
Combined with a couple of other challenges that I was facing at the time, I ended up with a diagnosis of depression, some medication and me suspending my studies during my third year. At the time, I wasn’t sure if I would return, but I kept the door open. I decided to go for a hard reset, changed my scenery completely and worked at a children’s holiday camp for a summer, which was just what I needed.
I came back refreshed, completed my third and fourth years, and went into teaching. It was a really difficult time, but after reaching my lowest point, I sought out the support that helped me get through it and then made some changes. I always try to encourage students and friends who are making tough decisions to think about the five-year test: in five years, is this going to be a major issue, or a minor blip? You don’t really know, but it’s often not as huge as it feels at the time, and sometimes that perspective can really help.
I still have crippling doubt at times and wonder what I’m doing, where it’s going and whether there’s a better way, but I now know the signs to look for. Again, to be a bit of an engineer, I call it preventative maintenance. You need to know when you need to pay attention to that strange noise going on in the engine and have a look at it, take it apart, investigate and fix it if you can; or when you can just live with it if you want to. Being proactive about mental health, general stress levels, particularly in the current times, I think is really, really important.
What’s your advice for students today?
As a student, take advantage of the academic and extracurricular opportunities that are offered, but be sensible and strategic about it. Also, while it’s important to do as well as you can in your core course, have other parts of your life to complement that. Find things that you’re passionate about – being interested makes you interesting. I personally follow that even today – I spend a lot of time on my core work, but a passion of mine is science communication. I’m a co-host of The Cosmic Shed podcast, which regular Physics World readers may be familiar with. I also love doing outreach and public engagement at festivals. I cycle and go on outdoor adventures.
Great opportunities do come up fortuitously, if you have networks of people whom you can trust and rely on, but also you can share opportunities with, and then make connections through – there’s give and take.


physicsworld--2020-11-10--Radiative cooling boosts solar cell voltage by as much as 25% - Physics World

Cheap and simple radiative cooling technologies can significantly increase the performance and lifespan of concentrated photovoltaic systems , according to researchers in the US .
They found that a simple radiative cooling structure can increase the voltage produced by the solar cells by around 25 % .
It also reduced operating temperatures by as much as 36 °C and the scientist claim this could dramatically extend the lifetime of photovoltaic systems .
Commercial silicon-based photovoltaic cells convert around 20 % of solar irradiation that falls on them into electricity .
Much of the rest is turned into heat , which @ @ @ @ @ @ @ efficiency and lifetimes both decrease as temperature goes up – especially in humid environments , ” explains Peter Bermel , an engineer at Purdue University .
“ The loss in efficiency is fundamental to how photovoltaics work.
” This is a particular issue for concentrated photovoltaic systems .
While using mirrors or lenses to focus sunlight on solar cells can boost efficiency , it also increases heating .
This can offset efficiency improvements and damage the photovoltaic cells , reducing their lifespan .
Current approaches to cooling such systems include forced air or @ @ @ @ @ @ @ heat sinks for conductive heat transfer .
But active cooling systems use energy and therefore reduce the net efficiency of the system .
They can also be complicated and expensive , increasing system costs and overall reliability .
Another potential option is radiative cooling .
Using thermal radiation to dissipate heat requires no additional power and the materials that enable it are often low cost .
To test the performance of radiative cooling , Bermel and his colleagues created a simple concentrated photovoltaic system .
In their setup , a mirror reflects sunlight @ @ @ @ @ @ @ it on a solar cell .
Using this design , they tested four cooling setups : natural convective cooling with a heatsink , no cooling , radiative cooling , and radiative cooling combined with convective cooling .
Radiative cooling was achieved by sandwiching the solar cell between two layers of soda-lime glass , which is known to be a good broadband radiative cooler .
These setups were tested outside , with multiple experiments conducted on different days in various conditions covering a wider range of heat loads .
The results are reported in @ @ @ @ @ @ @ that radiative cooling resulted in a 5–36 °C drop in the temperature of the system , depending on weather conditions , compared with the setups without radiative cooling .
Bermel told Physics World that the largest temperature difference was recorded with radiative cooling on its own , but the lowest absolute temperatures occurred when it was used in tandem with convective cooling .
These temperature drops caused a relative increase in open-circuit voltage for the solar cells of between 8–27 % .
This is “ roughly proportional to efficiency , ” Bermel says @ @ @ @ @ @ @ the scientists also simulated the impact of cooling on the lifespan of the solar cells .
This suggests that radiative cooling could extend the lifetime of concentrated photovoltaic cells by a factor of 4–15 .
According to the researchers , the results demonstrate that radiative cooling provides benefits in all weather conditions .
But Bermel ’ s colleague , graduate student Ze Wang , also at Purdue University , cautions that radiative cooling probably will not be suitable for cooling concentrated photovoltaic systems on its own .
Other systems would be needed to @ @ @ @ @ @ @ Radiative cooling is a very good auxiliary cooling mechanism , which requires no extra energy , performs well at high temperatures , and adds little weight to the whole system , ” Wang says .
“ However , in most cases , radiative cooling serves as an add-on to the existing cooling system utilizing convection or conduction , in order to improve the overall performance.
” However , radiative cooling does not perform well in low-temperature conditions , Wang explains .
This is because the temperature difference between the solar cell and the @ @ @ @ @ @ @ the potential of radiative cooling .
This is a particular issue when there are no low-temperature absorbers , such as a clear sky , around .
Radiative cooling materials are also not limited to the soda-lime glass .
“ We could work on the materials or structures of the coolers in the future to further improve the emittance profile , ” Wang says .

Chilling out radiative cooling could boost solar cell performance. (Courtesy: Shutterstock/ermess)
Cheap and simple radiative cooling technologies can significantly increase the performance and lifespan of concentrated photovoltaic systems, according to researchers in the US. They found that a simple radiative cooling structure can increase the voltage produced by the solar cells by around 25%. It also reduced operating temperatures by as much as 36 °C and the scientists claim this could dramatically extend the lifetime of photovoltaic systems.
Commercial silicon-based photovoltaic cells convert around 20% of solar irradiation that falls on them into electricity. Much of the rest is turned into heat, which must be effectively managed. “Photovoltaic efficiency and lifetimes both decrease as temperature goes up – especially in humid environments,” explains Peter Bermel, an engineer at Purdue University. “The loss in efficiency is fundamental to how photovoltaics work.”
This is a particular issue for concentrated photovoltaic systems. While using mirrors or lenses to focus sunlight on solar cells can boost efficiency, it also increases heating. This can offset efficiency improvements and damage the photovoltaic cells, reducing their lifespan.
Complicated and expensive cooling
Current approaches to cooling such systems include forced air or liquid cooling, or the use of heat sinks for conductive heat transfer. But active cooling systems use energy and therefore reduce the net efficiency of the system. They can also be complicated and expensive, increasing system costs and overall reliability.
Another potential option is radiative cooling. Using thermal radiation to dissipate heat requires no additional power and the materials that enable it are often low cost.
To test the performance of radiative cooling, Bermel and his colleagues created a simple concentrated photovoltaic system. In their set-up, a mirror reflects sunlight upwards and through a lens to focus it on a solar cell. Using this design, they tested four cooling set-ups: natural convective cooling with a heatsink, no cooling, radiative cooling, and radiative cooling combined with convective cooling. Radiative cooling was achieved by sandwiching the solar cell between two layers of soda-lime glass, which is known to be a good broadband radiative cooler.
These setups were tested outside, with multiple experiments conducted on different days in various conditions covering a wider range of heat loads. The results are reported in the journal Joule.
Temperature drop
The researchers found that radiative cooling resulted in a 5–36 °C drop in the temperature of the system, depending on weather conditions, compared with the set-ups without radiative cooling. Bermel told Physics World that the largest temperature difference was recorded with radiative cooling on its own, but the lowest absolute temperatures occurred when it was used in tandem with convective cooling.
These temperature drops caused a relative increase in open-circuit voltage for the solar cells of between 8–27%. This is “roughly proportional to efficiency,” Bermel says. Using temperature data from the experiments the scientists also simulated the impact of cooling on the lifespan of the solar cells. This suggests that radiative cooling could extend the lifetime of concentrated photovoltaic cells by a factor of 4–15.
According to the researchers, the results demonstrate that radiative cooling provides benefits in all weather conditions. But Bermel’s colleague, graduate student Ze Wang, also at Purdue University, cautions that radiative cooling probably will not be suitable for cooling concentrated photovoltaic systems on its own. Other systems would be needed to ensure cooling in all conditions.
Auxiliary cooling mechanism
“Radiative cooling is a very good auxiliary cooling mechanism, which requires no extra energy, performs well at high temperatures, and adds little weight to the whole system,” Wang says. “However, in most cases, radiative cooling serves as an add-on to the existing cooling system utilizing convection or conduction, in order to improve the overall performance.”
However, radiative cooling does not perform well in low-temperature conditions, Wang explains. This is because the temperature difference between the solar cell and the air is too small to fully exploit the potential of radiative cooling. This is a particular issue when there are no low-temperature absorbers, such as a clear sky, around.
Radiative cooling materials are also not limited to the soda-lime glass. “We could work on the materials or structures of the coolers in the future to further improve the emittance profile,” Wang says.


physicsworld--2020-11-11--Machine learning spots topological phase transitions in experimental data - Physics World

A machine-learning tool called diffusion maps has been used to identify topological phase transitions in experimental data .
The research was done by teams led by Mordechai Segev and Ronen Talmon at the Technion-Israel Institute of Technology , who report their results in Physical Review Letters .
Their method requires no prior knowledge about the system , and it found a phase transition in the data that was not predicted by current theory .
Their method can potentially help analyse data from complex quantum many-body experiments and improve our understanding of topological phases .
A recent addition to the familiar @ @ @ @ @ @ @ matter , topological phases have a non-local nature that makes them both interesting and challenging to detect .
Technion ’ s Eran Lustig , one of the lead researchers on this work , uses the analogy of a tornado : one can not tell that a tornado is a huge swirling vortex from just a tiny patch of it .
Topological phases are typically identified by studying the unique evolution of edge states of the system , which requires access to a significant part of the material .
Or Yair , the other @ @ @ @ @ @ @ that the diffusion-maps algorithm is well suited to detect non-local signatures of topological phases .
Given a set of experimental data points , it checks the local neighbourhood of a point to find nearby points and gradually zooms out to find relationships with points that appear far apart .
The researchers first tested their method on simulated data from a system with a known phase transition , called the Haldane model .
It is a hexagonal lattice system with interactions between nearest neighbours and the next nearest neighbours .
Its two triangular sublattices @ @ @ @ @ @ @ the amount of staggering passes a critical value , the system undergoes a phase transition from a topological phase to a normal phase .
To test the capabilities of diffusion maps , they used a bulk state excitation instead of one on the edge .
The phase-transition location in the parameter space found by diffusion maps matched the theoretical position .
Using bulk states for detection can be useful for systems with no well-defined edges like cold atom clouds or systems where edges are hard to access or control .
They also probed @ @ @ @ @ @ @ the system to show that the procedure works even with limited data .
Following the run on simulated data , the researchers used real data from a coupled waveguides experiment .
With no information about the system or noise sources , their algorithm was able to find a “ cusp ” in the data – a signature that a phase transition had taken place .
They also observed a weaker cusp related to another phase transition unaccounted for in the theoretical model .
With this insight , the researchers were able to identify @ @ @ @ @ @ @ .
Machine-learning tools also help researchers with the interpretation of the large amounts of data generated from modern experiments with many degrees of freedom .
The diffusion-maps method is a kind of manifold learning algorithm , which tries to find a lower-dimensional representation of data .
A simple example of dimensionality reduction is that of a line drawn on a 2D plane – while it appears that one needs two co-ordinates to specify points on a line , in reality it is just a 1D object or “ manifold ” embedded in a @ @ @ @ @ @ @ increasing attention in condensed matter and optical systems because of their association with robust physical phenomena .
In these phases , some properties like edge transport or conductance remain unaffected even if one changes the shape of the system or introduces imperfections and other kinds of disorder .
In the past , scientists have tried using neural networks or unsupervised learning methods to identify phase transitions in experimental data , but these methods need trainable data or knowledge of the experimental set-up .
The diffusion-maps method , on the other hand , does @ @ @ @ @ @ @ is inherently designed to extract non-local features in the data .
The researchers find their results very promising .
“ I think it ’ s really important to discuss the vision and the surprises ” , Segev comments , “ [ we want ] to be able to use this method to identify phase transitions in quantum many-body systems – where the theory is incomputable , and it is virtually impossible to make real predictions for the experiments .
”

Experimental data: excitations in a lattice of optical waveguides. (Courtesy: Eran Lustig et al./Physical Review Letters; data from J Noh et al./Nature Physics)
A machine-learning tool called diffusion maps has been used to identify topological phase transitions in experimental data. The research was done by teams led by Mordechai Segev and Ronen Talmon at the Technion-Israel Institute of Technology, who report their results in Physical Review Letters. Their method requires no prior knowledge about the system, and it found a phase transition in the data that was not predicted by current theory. Their method can potentially help analyse data from complex quantum many-body experiments and improve our understanding of topological phases.
A recent addition to the familiar solid, liquid or gaseous phases of matter, topological phases have a non-local nature that makes them both interesting and challenging to detect. Technion’s Eran Lustig, one of the lead researchers on this work, uses the analogy of a tornado: one cannot tell that a tornado is a huge swirling vortex from just a tiny patch of it. Topological phases are typically identified by studying the unique evolution of edge states of the system, which requires access to a significant part of the material.
Or Yair, the other lead researcher on the project, explained that the diffusion-maps algorithm is well suited to detect non-local signatures of topological phases. Given a set of experimental data points, it checks the local neighbourhood of a point to find nearby points and gradually zooms out to find relationships with points that appear far apart.
Haldane model
The researchers first tested their method on simulated data from a system with a known phase transition, called the Haldane model. It is a hexagonal lattice system with interactions between nearest neighbours and the next nearest neighbours. Its two triangular sublattices can be staggered in energy. As the amount of staggering passes a critical value, the system undergoes a phase transition from a topological phase to a normal phase.
To test the capabilities of diffusion maps, they used a bulk state excitation instead of one on the edge. The phase-transition location in the parameter space found by diffusion maps matched the theoretical position. Using bulk states for detection can be useful for systems with no well-defined edges like cold atom clouds or systems where edges are hard to access or control. They also probed the system using only one eigenstate of the system to show that the procedure works even with limited data.
Following the run on simulated data, the researchers used real data from a coupled waveguides experiment. With no information about the system or noise sources, their algorithm was able to find a “cusp” in the data – a signature that a phase transition had taken place. They also observed a weaker cusp related to another phase transition unaccounted for in the theoretical model. With this insight, the researchers were able to identify a higher-order process that produced that transition.
Machine-learning tools also help researchers with the interpretation of the large amounts of data generated from modern experiments with many degrees of freedom. The diffusion-maps method is a kind of manifold learning algorithm, which tries to find a lower-dimensional representation of data. A simple example of dimensionality reduction is that of a line drawn on a 2D plane – while it appears that one needs two co-ordinates to specify points on a line, in reality it is just a 1D object or “manifold” embedded in a 2D space.
The road ahead
Topological phases are receiving increasing attention in condensed matter and optical systems because of their association with robust physical phenomena. In these phases, some properties like edge transport or conductance remain unaffected even if one changes the shape of the system or introduces imperfections and other kinds of disorder.
In the past, scientists have tried using neural networks or unsupervised learning methods to identify phase transitions in experimental data, but these methods need trainable data or knowledge of the experimental set-up. The diffusion-maps method, on the other hand, does not need any prior knowledge, and is inherently designed to extract non-local features in the data.
The researchers find their results very promising. “I think it’s really important to discuss the vision and the surprises”, Segev comments, “[we want] to be able to use this method to identify phase transitions in quantum many-body systems – where the theory is incomputable, and it is virtually impossible to make real predictions for the experiments.”