Physicists demonstrate rotated light images

(PhysOrg.com) -- In what might at first seem obvious, but isn't after further thinking, a group of physicists from the United States and Canada have demonstrated, for the first time, that images generated by light, can be rotated via a rotating medium. In a paper published in Science, physicists Sonja Franke-Arnold, Graham Gibson, Robert W. Boyd and Miles J. Padgett describe how they were able to replicate the effects of light shifting via a moving medium, in a spinning medium, opening the door to a possible new way of encoding transmitted images.

Scientists have long known that when a light is shone through certain moving material, that the light itself can be shifted along with it, due to the photons being absorbed and then released by the atoms in the medium. The effect has been demonstrated over the years and can be seen in the simplest of venues, such as light shining through a waterfall. Until now however, no one has shown that a similar effect might apply to a rotating medium.

The idea is that if a beam of light, projected in a certain shape, such as a square for example, were to be shone through a spinning medium, such as a round block of glass, the image would emerge on the other side, but not exactly opposite; it would be off, just a little bit, in the direction of the spin. The amount of shifting would of course depend on both the speed of revolution of the cylinder and on the medium used, as some, such as rubies are able to cause more of a drag, per se, on the light as it moves through, than others.

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Image rotation filmed for a light beam propagating through a 10cm length of ruby rod, spinning the rod first clockwise and then anti-clockwise (as viewed from the camera position). Video: Science, DOI: 10.1126/science.1203984

To test this theory, the team created a square beam of green light, which they then directed at a spinning cylinder made entirely of ruby. The light was sufficiently strong enough to shine all the way through the cylinder, creating a square image on the other side. To see if the image was being rotated as the cylinder spun, the exact location of the projected image was noted, then the cylinder was spun in the opposite direction, to see if it would then be in a different position; which of course, it was. With the cylinder spinning at 30 revolutions per second, they found that the projected image was rotated about a third of a degree. They also found that increasing the amount of light tended to increase the amount of rotation of the projected image, in some cases, by as much as ten degrees.

The research team note in their paper that they believe one application of this phenomenon could be its use in image encoding, just as current methods now include an image?s intensity.

More information: Rotary Photon Drag Enhanced by a Slow-Light Medium, Science 1 July 2011: Vol. 333 no. 6038 pp. 65-67 DOI: 10.1126/science.1203984

ABSTRACT

Transmission through a spinning window slightly rotates the polarization of the light, typically by a microradian. It has been predicted that the same mechanism should also rotate an image. Because this rotary photon drag has a contribution that is inversely proportional to the group velocity, the image rotation is expected to increase in a slow-light medium. Using a ruby window under conditions for coherent population oscillations, we induced an effective group index of about 1 million. The resulting rotation angle was large enough to be observed by the eye. This result shows that rotary photon drag applies to images as well as polarization. The possibility of switching between different rotation states may offer new opportunities for controlled image coding.

via PhysicsWorld

2010 PhysOrg.com

Invisibility carpet cloak can hide objects from visible light

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When an input beam (black arrow) reflects off (a) a bump without a cloak, the bump causes a perturbation. When the beam reflects off (b) a bump covered by a cloak, the cloak masks the bump, and the reflected beam is reconstructed as if the bump did not exist. (c) Light after reflection from a flat mirror, a bump without a cloak, and a cloaked bump, at three different wavelengths. Image credit: Majid Gharghi, et al. 2011 American Chemical Society

(PhysOrg.com) -- Most of the invisibility cloaks that have been demonstrated to date conceal objects at frequencies that are not detectable by the human eye. Designing invisibility cloaks that can conceal objects from visible light has been more challenging due to the strict material requirements. But in a new study, researchers have fabricated a carpet cloak that can make objects undetectable in the full visible spectrum.

The researchers, led by Prof. Xiang Zhang at the University of California, Berkeley, and Lawrence Berkeley National Laboratory, have published their study in a recent issue of Nano Letters.

As the researchers explain, most previous invisibility cloaks have used metallic metamaterials for cloaking at microwave frequencies. But at optical frequencies, the metal absorbs too much light and leads to significant metallic loss, and Berkeley and other groups have had to design dielectric cloaks at infrared frequencies. More recently, researchers at University of Birmingham (UK) have experimented with using uniaxial crystals as the cloak material, which can enable cloaking in visible frequencies, but only for a certain polarization of light.

In the current study, the researchers used a technique called quasi conformal mapping (QCM) to conceal an object with a height of 300 nm and a width of 6 µm underneath a reflective ?carpet cloak.? The carpet itself has the appearance of a smooth optical mirror, so that the object and the bump that the object makes underneath the carpet are undetectable by visible light.

?The carpet cloak means that you conceal the object under a layer, which we call carpet, but you see the carpet like a normal mirror, as if it is flat with no bump caused by putting the object underneath,? Zhang told PhysOrg.com. ?This way, the observer won't recognize something is concealed underneath.?

In order to guide visible light around the concealed object, the researchers had to make light travel at different speeds while approaching the bump. They achieved this by designing the materials to have a variable refractive index, transforming them into metamaterials, since they don?t appear in nature. The researchers placed a silicon nitride waveguide on a transparent nanoporous silicon oxide substrate that they specially developed to have a much lower refractive index than that of the waveguide. Using nanofabrication techniques, the researchers etched tiny holes into the nitride to make a desired pattern, giving the waveguide the cloaking refractive index profile.

?The concept of the carpet cloak was originally suggested so that you can design a certain pattern for a given size of the bump, and hide an object of arbitrary shape under that,? Zhang said. ?If you need to make a bigger size bump to hide a bigger object, a new hole pattern will be required.?

With this refractive index profile, along with the transparency of both the waveguide and the substrate, the cloak could completely conceal an object by producing a light beam profile identical to a beam reflected from a flat carpet with no object underneath.

?This device is among the first cloak devices that operate at visible frequencies; the other very recent visible light cloaks operate based on a principle that relies on a certain polarization of light, whereas the quasi-conformal-based principle does not rely on the polarization,? Zhang said. ?Of course, the waveguide geometry entails different operation for different polarizations, which is extrinsic to the QCM design.?

In addition to cloaking, the new technique provides an important step toward implementing optical transformation structures in the visible range. Using transformation optics (TO), researchers can manipulate light for applications such as powerful microscopes and computers.

?The carpet cloak is an example of a wide family of devices that can be made based on transformation optics,? Zhang said. ?Besides invisibility, all kinds of optical illusion schemes can be made based on the concept, where the observer receives a different impression when looking at an object. The capability to manipulate light propagation can be used in energy devices, optical computing devices, and beyond, wherever it is desired to have full control on the light path; TO lets us redirect light and re-route it.?

More information: Majid Gharghi, et al. ?A Carpet Cloak for Visible Light.? Nano Letters. DOI: 10.1021/nl201189z

Copyright 2011 PhysOrg.com.

All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com.

Nano-LEDs emit full visible spectrum of light

 

(Left) A single nanodisk-nanorod LED viewed with a field-emission scanning electron microscope. (Right) Some colors of light emissions from nanodisk-nanorod LEDs - violet, blue, cyan, green, and yellow - viewed with an optical microscope. Image credit: Lu, et al. 2011 American Institute of Physics

Physicists from Taiwan have designed and fabricated nano-sized light-emitting diodes (LEDs) that emit light spanning the entire visible spectrum. Although the tiny full-color LEDs aren't intended for commercial lighting applications, they should be useful in high-resolution microscopy and subwavelength photolithography.

The researchers, Yu-Jung Lu, et al., from National Tsing-Hua University in Hsinchu, Taiwan, have published their study on the nano-LEDs in a recent issue of Applied Physics Letters.

The new nano-LEDs have a unique structure that consists of 40-nm-thick nanodisks sandwiched between two layers of nanorods, resulting in a nanodisk-in-nanorod geometry. The nanodisks are made of indium gallium nitride (InGaN), a semiconducting material that is widely used in LEDs and solar cells, while the nanorods are made of gallium nitride (GaN). However, InGaN LEDs capable of emitting light of the entire visible spectrum have not been achieved until now.

?The InGaN/GaN nanodisk/nanorod structure is similar to a well-known quantum well structure, but in a reduced dimensionality (reduction in lateral sizes),? coauthor Shangjr Gwo, a physics professor at National Tsing-Hua University, told PhysOrg.com. ?The InGaN nanodisks sandwiched between the p- and n-GaN regions act as the full-color visible-light emitters when electrons and holes are injected across the p-n junction at a forward bias voltage. The electroluminescent light comes from the electron-hole recombination within the InGaN nanodisks.?

As the researchers explained, the key to achieving full-color LEDs was overcoming large lattice strains, which degrade long-wavelength emissions. The InGaN/GaN nanorod system resolves this issue due to the strain relaxation in the nanostructured geometry.

The researchers hope that these full-color nano-LEDs can be used in high-resolution imaging techniques that can resolve ultrasmall subwavelength features of objects. To do this, these techniques must overcome the diffraction limit, which is a fundamental limit on imaging resolution caused by the spreading out ? or ?diffraction? ? of waves. Imaging techniques can get around this limit by using evanescent waves, which reveal information on objects? subwavelength features, but also decay exponentially away from the object. Due to the short range of the evanescent waves, imaging techniques that detect them are based on near-field optics.

One of these techniques is scanning near-field optical microscopy (SNOM), which uses a tiny probe to generate and retrieve evanescent waves. One of the biggest challenges in SNOM is getting a light source that is small and versatile enough to work on this probe, and that?s where the new nano-LEDs come in. While previous research has demonstrated the advantages of using nano-LEDs on the probes, this is the first time that a nano-LED with a full-color range has been available.

?For microscopy, we can use the nano-LED as a localized excitation light source at a chosen wavelength to selectively excite specific fluorescent molecules,? Lu said.

In their study, the researchers experimentally demonstrated using the nanodisk-in-nanorod LEDs for subwavelength photolithography, in which light is used to create a pattern on a light-sensitive material. They predict that, by fabricating the nano-LEDs onto the SNOM probe tips, they could achieve better spatial control for future subwavelength photolithography.

?For the applications of photolithography, the freedom of using nano-LEDs at any wavelength broadens the choice of photoresist and allows for the control of their photo-response,? Lu said.

 

Novel device sheds light on the beauty of science

Novel device sheds light on the beauty of science

Monmorillonite particles, cut apart to reveal that one of them is hollow.

The wonder of science often comes from the endless possibilities opened up by each successive discovery and the unexpected findings that result. Scientists at the University of Bristol now have a new tool that will yield yet more and unprecedented levels of information – and crucially, without disturbing the natural, physical state of the object under scrutiny.

The past few months have seen physicists at Bristol’s Interface Analysis Centre vying for time on the dualbeam instrument, which as centre Director Dr. Tom Scott says, “unlocks the key to a whole new world”.

It has so far produced hundreds of images that are as beautiful as they are revelatory, and those at the IAC are keen to see what more the dualbeam can do, working with colleagues from across the University to delve into all matter, from diamonds to insect ears.

The dualbeam looks at surface structures with a resolution of less than a nanometre – the equivalent of ten millionths of the thickness of a human hair.  The resolution of the images produced is just one nanometre, which is beyond miniscule, given that it takes 1,000 nanometres to make one micron, and 1,000 microns constitute a single millimetre. 

The dualbeam is so called because it operates using two systems – a focused ion beam (FIB) and a high spec field emission scanning electron microscope (SEM).  It operates using gallium ions derived from a liquid metal ion source that are directed at the surface in a tightly controlled beam in which individual atoms are travelling at speeds  of up to one million miles an hour. The ion beam can be precisely controlled to remove material from tightly defined areas – essentially performing micro and even nano-surgery on almost any material.

A nano-wire made using ion beam milling for gas sensing applications. It also happens to look like a small-scale version of the Clifton suspension bridge.

Unlike other techniques used for dissecting materials, the dualbeam can extract information and capture images without causing any detectable damage except over a tiny area.  It can also deposit materials such as gold and platinum, known for their conductivity, on to the surface structure, providing insights into the composition and behaviour of materials.

For physicists looking for quantum wells, biologists looking at the structure of membranes in the ears of tree crickets, and engineers keen to understand the nanostructure of exotic alloys, the dualbeam seems to hold the key to success. 

“It makes things possible which were previously considered impossible, it’s at the heart of what makes science beautiful,” says Dr. Scott.  “It can do things in such a precisely defined way to such a high degree of accuracy that it really is incredible.  In fact, it’s difficult to comprehend just how small a scale this thing works on.”

Some of the project proposals under consideration that would make use of the dualbeam include an examination of the ears of Indian tree crickets, where the dualbeam could be used to slice and view in three dimensions reconstructions of cricket ears.  The findings could ultimately inform medical advancements in hearing devices for humans.

Another involves examining the materials used to build nuclear power stations.  The rate at which they age, and the outputs produced as they do so, is of serious concern.  A closer examination of the microstructure of stainless steels, and the processes by which they accommodate strain when affected by thermal cycling in power stations, would yield significant information about potential failure risks that could subsequently be safeguarded against in the design of the next generation of power stations. 

The dualbeam could also be used in quantum cryptography, to devise ways of transmitting messages in a way that is resistant to attempts to tap into the source, using emitters constructed from a single photonic light source so small and so intricately encoded as to be virtually undetectable.

In biochemistry, researchers are looking at making actuators - “gold sandwiches” with a polymer filling which could swim through the bloodstream, collecting information that could be used to inform medical approaches to human disease.

Dissecting and reconstructing structures in three dimensions can take a matter of minutes or hours, depending on the volume of the material under scrutiny.  The dualbeam also has an automation capability which allows researchers to program it to carry out operational tasks, freeing them up to continue with something else. Dr. Scott compares it to a multi-faceted kitchen aid: “This machine basically does all the slicing and dicing, leaving you to concentrate on making a really fantastic meal.”

Dr. Scott is keen to seek out other collaborations that will test the boundaries of every discipline and put materials and this new tool through its paces:  “The dualbeam instrument is a clear example of the University’s commitment to groundbreaking developments in research. If we are going to be the leaders in the UK and internationally in terms of research we need to be pushing the boundaries of what is technically possible, and this new piece of equipment will certainly enable us to do that.”

Shining light on graphene sensors

Shining light on graphene sensors

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A light-sensitive graphene/polymer heterostructure.

National Physical Laboratory, together with an international team of scientists, have published research showing how light can be used to control graphene's electrical properties. This advance is an important step towards developing highly sensitive graphene-based electronic devices.

Graphene is an extraordinary two-dimensional material made of a single atomic layer of carbon atoms. It is the thinnest material known to man, and yet is one of the strongest ever tested.

It has unique properties which make it a very exciting material for a huge range of applications from high-speed electronics and solar cells, to super-sensors capable of detecting single molecules of toxic gases.

It is able to act as a sensor because its entire structure is exposed to its surroundings, and it reacts to any molecules that touch its surface. This reaction causes graphene's electrical properties to alter, i.e. it senses the molecules' presence.

In their paper published in the Journal of Advanced Materials, the team show that when graphene is coated with light-sensitive polymers its unique electrical properties can be precisely controlled and therefore exploited.

The polymers also protect graphene from contamination.

Light-modified graphene chips have already been used at NPL in ultra-precision experiments to measure the quantum of the electrical resistance.

In the future similar polymers could be used to effectively 'translate' information from their surroundings and influence how graphene behaves. This effect could be exploited to develop robust reliable sensors for smoke, poisonous gases, or any targeted molecule.

Seeing the light: Scientists bring plasmonic nanofields into focus

Seeing the light: Scientists bring plasmonic nanofields into focus

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By imaging fluorescence from gold within a bowtie-shaped plasmonic device, Berkeley Lab researchers gleaned the position of plasmonic modes just a few nanometers apart.

In typical plasmonic devices, electromagnetic waves crowd into tiny metal structures, concentrating energy into nanoscale dimensions. Due to coupling of electronics and photonics in these metal nanostructures, plasmonic devices could be harnessed for high-speed data transmission or ultrafast detector arrays. However, studying plasmonic fields in nanoscale devices presents a real roadblock for scientists, as examining these structures inherently alters their behavior.

“Whether you use a laser or a light bulb, the wavelength of light is still too large to study plasmonic fields in nanostructures. What’s more, most tools used to study plasmonic fields will alter the field distribution—the very behavior we hope to understand,” says Jim Schuck,  a staff scientist with Lawrence Berkeley National Laboratory (Berkeley Lab) who works in the Imaging and Manipulation of Nanostructures Facility at the Molecular Foundry.

Light microscopy plays a fundamental role in a scientist’s repertoire: the technique is easy to use and doesn’t inflict damage to a carefully crafted electronic circuit or delicate biological specimen. However, a typical nanoscale object of interest—such as a strand of DNA or a quantum dot—is well below the wavelength of visible light in size, which means the ability to distinguish one such object from another when they are closely spaced is lost.  Scientists are now challenging this limit using ‘localization’ techniques, which count the number of photons emanating from an object to help determine its position.

In previous work, Schuck and colleagues at the Molecular Foundry, a U.S. Department of Energy (DOE) Nanoscale Science Research Centers,  engineered bowtie-shaped plasmonic devices designed to capture, filter and steer light at the nanoscale. These nano-color sorter devices served as antennae to focus and sort light in tiny spaces to a desired set of colors or energies—crucial for filters and other detectors.

In this latest advance, Schuck and his Berkeley Lab team used their innovative imaging concept to visualize plasmonic fields from these devices with nanoscale resolution. By imaging fluorescence from gold within the bowtie and maximizing the number of photons collected from their bowtie devices, the team was able to glean the position of plasmonic modes—oscillations of charge that result in optical resonance—just a few nanometers apart.

“We wondered whether there was a way to use light already present in our bowties—localized photons—to probe these fields and serve as a reporter,” says Schuck. “Our technique is also sensitive to imperfections in the system, such as tiny structural flaws or size effects, suggesting we could use this technique to measure the performance of plasmonic devices in both research and development settings.”

In parallel with Schuck’s experimental findings, Jeff Neaton, Director of the Molecular Foundry ’s Theory of Nanostructured Materials Facility and Alex McLeod, an undergraduate student working at the Foundry, developed a web-based toolkit, designed to calculate images of plasmonic devices with open-source software developed at Massachusetts Institute of Technology. For this study, the researchers simulated adjusting the structure of a double bowtie antenna by a few nanometers to study how changing the size and symmetry of a plasmonic antenna affects its optical properties.

“By shifting their structure by just a few nanometers, we can focus light at different positions inside the bowtie with remarkable certainty and predictability,” said McLeod. “This work demonstrates that these nanoscale optical antennae resonate with light just as our simulations predict.”

Useful for researchers studying plasmonic and photonic structures, this toolkit will be available for download on nanoHUB, a computational resource for nanoscience and technology created through the National Science Foundation’s Network for Computational Nanotechnology.

“This work really exemplifies the very best of what the Molecular Foundry is about,” said Neaton, who is also Acting Deputy Director of Berkeley Lab’s Materials Sciences Division. “Three separate Foundry facilities—Imaging, Nanofabrication and Theory—collaborated on a significant advance in our understanding of how visible light can be localized, manipulated, and imaged at the nanoscale.”

A paper reporting this research titled, “Non-perturbative visualization of nanoscale plasmonic field distributions via photon localization microscopy,” appears in Physical Review Letters and is available to subscribers online. Co-authoring the paper with Schuck, McLeod and Neaton were Alexander Weber-Bargioni, Zhaoyu Zhang, Scott Dhuey, Bruce Harteneck and Stefano Cabrini.

Portions of this work at the Molecular Foundry were supported by DOE’s Office of Science.  Support for this work was also provided by the National Science Foundation through the Network for Computational Nanotechnology.

Exciting atoms on the move: Fine-tuned laser light activates oxygen atoms to escape the surface

Exciting atoms on the move: Fine-tuned laser light activates oxygen atoms to escape the surface

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Exciton-driven desorption of highly energetic neutral oxygen atoms from nanostructured CaO. This work was chosen for the cover of The Journal of Physical Chemistry C, January 27, 2011.

(PhysOrg.com) -- A new way to accelerate and remove oxygen atoms from thin films of calcium oxide has been discovered by a team of scientists from Pacific Northwest National Laboratory, University College of London, and Tohoku University. By choosing the appropriate laser wavelength, they found a way to remove oxygen at many times the speed of sound. The atoms escape from the surface of nanostructured films of calcium oxide.

This research has implications for research and development in photochemistry, catalysis, and microelectronics. It was chosen as the cover of The Journal of Physical Chemistry C for January 27, 2011.

Focusing on new and old questions, basic research helps us understand the pure principles of science and provides the building blocks for solving big scientific problems. In this new research, a team of materials and theoretical physicists collaborated to answer questions about gaining greater control over thin film structures. Thin films are important for research in photochemistry, catalysis, and microelectronics, and have applications in industries such as pharmaceuticals and energy technologies.

This project involves desorption of neutral oxygen atoms from a thin film of calcium oxide (CaO). Desorption is the process of removing atoms or other particles from a surface. By shining an ultraviolet-laser on the high-surface-area material, neutral oxygen atoms are desorbed at several times the speed of sound.

Researchers used a technique developed at PNNL called reactive ballistic deposition to grow a nanostructured film of CaO. Using laser pulses to excite the film, researchers applied time-of-flight techniques to measure the kinetic energy and yield of desorbed oxygen atoms. By selecting the laser wavelength, they were able to produce highly energetic atoms from the film surface. The electronic excitation, known as exciton, is initially formed in the material's bulk. Excitons are mobile and can transfer electronic energy to the surface of the film. Once on the surface, some of the exciton energy is channeled into desorption of neutral oxygen atoms at high speed.

This research shows that it is possible to manipulate particular molecular structures on a material surface by tuning the laser wavelength. This discovery could be useful for manipulating surface structures at the atomic level. Modifying thin films on a very fine scale may allow scientists better control over thin film structures.

Researchers continue to work on developing and exploring other mechanisms for thermal desorption processes from oxide materials.

New material enables 'information sorting' at the speed of light

New material enables 'information sorting' at the speed of light

Artistic impression of metamaterial structure consisting of gold nanorods illuminated by two interacting light beams. Courtesy of R. McCarron.

(PhysOrg.com) -- An international team of scientists led by King’s College London has taken a step closer towards developing optical components for super-fast computers and high-speed internet services of the future. This has the potential to revolutionise data processing speeds by transmitting information via light beams rather than electric currents.

The researchers are studying the science of ‘nanoplasmonic devices’ whose key components are tiny nanoscale metal structures, more than 1000 times smaller than the size of a human hair, that guide and direct light.

Information is routinely sorted and directed in different directions to allow computing, internet connections or telephone conversations to take place. At present, however, computers process information by encoding it in electric signals.

It would be much faster to process and transmit information in the form of light instead of electric signals, but until now, it has been difficult for the light beams to be ‘changed’, that is to interact with other beams of light, while travelling through a material, and this has held up progress.

The scientists have solved this by designing a new artificial material, which allows light beams to interact efficiently and change intensity, therefore allowing information to be sorted by beams of light at very high speeds. The structure of the tailor-made material is similar to a stack of nanoscale rods, along which light can travel and, most importantly, interact.

Professor Anatoly Zayats, in the Department of Physics at King’s, explains: ‘If we were able to control a flow of light in the same way as we control a flow of electrons in computer chips, a new generation of data processing machines could be built, which would be capable of dealing with huge amounts of information much faster than modern computers.

‘The new material we have developed, often called ‘metamaterial’, could be incorporated into existing electronic chips to improve their performance, or used to build completely new all-optical chips and therefore revolutionise data processing speeds.

‘While there are many challenges to overcome, we would anticipate that in the future this faster technology could be in our PCs, mobile phones, aeroplanes and cars, for example.’

Other members of the team involved in this latest research include Argonne National Laboratory in the USA; University of North Florida; University of Massachusetts at Lowell; and Queen’s University of Belfast in the UK.

The research is published in the journal Nature Nanotechnology.

Shining light on graphene sensors

Shining light on graphene sensors

Enlarge

A light-sensitive graphene/polymer heterostructure.

National Physical Laboratory, together with an international team of scientists, have published research showing how light can be used to control graphene's electrical properties. This advance is an important step towards developing highly sensitive graphene-based electronic devices.

Graphene is an extraordinary two-dimensional material made of a single atomic layer of carbon atoms. It is the thinnest material known to man, and yet is one of the strongest ever tested.

It has unique properties which make it a very exciting material for a huge range of applications from high-speed electronics and solar cells, to super-sensors capable of detecting single molecules of toxic gases.

It is able to act as a sensor because its entire structure is exposed to its surroundings, and it reacts to any molecules that touch its surface. This reaction causes graphene's electrical properties to alter, i.e. it senses the molecules' presence.

In their paper published in the Journal of Advanced Materials, the team show that when graphene is coated with light-sensitive polymers its unique electrical properties can be precisely controlled and therefore exploited.

The polymers also protect graphene from contamination.

Light-modified graphene chips have already been used at NPL in ultra-precision experiments to measure the quantum of the electrical resistance.

In the future similar polymers could be used to effectively 'translate' information from their surroundings and influence how graphene behaves. This effect could be exploited to develop robust reliable sensors for smoke, poisonous gases, or any targeted molecule.