Author Archives: Megan

1. London Light Celebrates the International Day of Light

   May 26, 2021 8:35 am Leave a Comment

   On Thursday, 20 May, the London Institute for Advanced Light Technologies hosted The Shared Language of Light, an interdisciplinary panel event to celebrate light in all its forms.

   The event was the culmination of Lighting Up 2021, a series of events that London Light hosted to celebrate the UNESCO International Day of Light. Lighting Up 2021 included an art project with light enthusiasts from around the globe, and the chance for people to share short videos about an element of light which delighted them (the submissions can be viewed on the London Light Instagram page)

   The Shared Language of Light was hosted by artist and curator Dr Shelley James and after a short introduction from London Light co-director Anatoly Zayats, the panelists discussed the Lighting Up submissions and why they found them inspiring.

   The panellists were physicist Dr James Millen, architect Mark Major, art publisher Kailas Elmer, colour specialist Marianne Shillingford and astronomer Bob Mizon OBE.

   You can watch the event below:

   Of the event, Professor Anatoly Zayats said ‘This was a fantastic event which captured all the essence of the International Day of Light and touched upon many aspects from the science of light to simply how light brightens our lives. It is light that made the event possible this year, both figuratively and literally, by connecting our computers through the internet. The discussions and presentations vividly demonstrated the role of light at very small scales, acting as a tool in nanotechnology, and at large scales helping us to study the Universe, the problems of light pollution, and our perception of colours and lighting. Our day-to-day job at the London Institute for Advanced Light Technologies is to study light, but it is important and extremely informative to have a broader conversation on the subject and engage with artists and society. We are proud to host this event and facilitate this fantastic interdisciplinary collaboration.’

   You can watch the results of the Lighting Up art project below:

2. Light-emitting tattoo engineered for the first time

   March 15, 2021 11:17 am Leave a Comment

   Scientists from London Light and the IIT –Istituto Italiano di Tecnologia (Italian Institute of Technology) have created a temporary tattoo with light-emitting technology used in TV and smartphone screens, paving the way for a new type of “smart tattoo” with a range of potential use.

   The technology, which uses organic light-emitting diodes (OLEDs), is applied in the same way as water transfer tattoos. That is, the OLEDs are fabricated on to temporary tattoo paper and transferred to a new surface by being pressed on to it and dabbed with water.

   

   The researchers, who described the process in a new paper in the journal Advanced Electronic Materials, say it could be combined with other tattoo electronics to, for instance emit light when an athlete is dehydrated, or when we need to get out of the sun to avoid sunburn. OLEDs could be tattooed on packaging or fruit to signal when a product has passed its expiry date or will soon become inedible, or used for fashion in the form of glowing tattoos.

   Professor Franco Cacialli (co-director of London Light), senior author of the paper, said: “The tattooable OLEDs that we have demonstrated for the first time can be made at scale and very cheaply. They can be combined with other forms of tattoo electronics for a very wide range of possible uses. These could be for fashion – for instance, providing glowing tattoos and light-emitting fingernails. In sports, they could be combined with a sweat sensor to signal dehydration.

   “In healthcare they could emit light when there is a change in a patient’s condition – or, if the tattoo was turned the other way into the skin, they could potentially be combined with light-sensitive therapies to target cancer cells, for instance.

   “Our proof-of-concept study is the first step. Future challenges will include encapsulating the OLEDs as much as possible to stop them from degrading quickly through contact with air, as well as integrating the device with a battery or supercapacitor.”

   The OLED device the researchers developed is 2.3 micrometres thick in total (less than one 400^th of a millimetre) – about a third of the length of a single red blood cell. It consists of an electroluminescent polymer (a polymer that emits light when an electric field is applied) in between electrodes. An insulating layer is placed in between the electrodes and the commercial tattoo paper.

   The light-emitting polymer is 76 nanometres thick (a nanometre is a millionth of a millimetre) and was created using a technique called spin coating, where the polymer is applied to a substrate which is spun at high speed, producing an extremely thin and even layer.

   Once they had built the technology, the team applied the tattooable OLEDs, which emitted green light, on to a pane of glass, a plastic bottle, an orange, and paper packaging.

   Senior author Professor Virgilio Mattoli, researcher at Italian Institute of Technology said: “Tattoo electronics is a fast-growing field of research. At the Italian Institute of Technology we have previously pioneered electrodes that we have tattooed onto people’s skin that can be used to perform diagnostic tests such as electrocardiograms. The advantage of this technology is that it is low-cost, easy to apply and use, and washes off easily with soap and water.”

   OLEDs were first used in a flatscreen TV 20 years ago. Among the advantages of the technology are that they can be used on flexible, bendy surfaces, and that they can be made from liquid solvents. This means they are printable, providing a cheap way to create bespoke new OLED designs.

   The Full Article is available in the Advance Electronic Materials

   Image Credit: Barsotti – Italian Institute of Technology

3. Lighting Up 2021

   February 2, 2021 10:22 am Leave a Comment

   

   To celebrate the International Day of Light we are hosting a 24 hour Zoom call with people from all around the world to show the sun rising and setting around the globe. We will speed up the recording of the composite zoom screens to create a rich and subtly-shifting patchwork.

   Our event is today at 4pm! Click here to join

   Bringing a spark of light to 2021!

   A huge thank you to everyone who submitted a video to Lighting Up 2021 A streaming event to be held on 20 May 2021 with a panel of experts.

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   A number of submissions from our Lighting Up 2021 call will be selected by a panel of experts for a special screening. This will open a public debate about the shared language of light on Thursday 20th of May at 4pm GMT. 

   Join our event here today at 4pm

   Hosted by Dr Shelley James our panelists include:

   
   

   • Mark Major – Lighting designer
   • Kailas Elmer – Publisher, Trebuchet Magazine
   • Dr James Millen – Physicist King’s College London
   • Bob Mizon OBE – Astronomer and Co-ordinator of the Commission for Dark Skies
   •  Marianne Shillingford – Colour specialist and Creative Director of Dulux,

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   Image credit: Megan Grace-Hughes Artwork:Prismatica by RAW Design in collaboration with Atomic3

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   A couple of examples are below as a starting point – but we are looking forward to seeing your creative spark! If you include music or soundscape, please can you make sure that you have permission to use it, own the copywrite or that it is royalty free

    

   And for more information, please contact us at london-light@kcl.ac.uk

    

   

   Many thanks to Nature Photonics for their support for this event.

    

   

4. Taking Maxwell’s equations for a spin

   9:14 am Leave a Comment

   John Clerk Maxwell developed his famous Maxwell Equations whilst working at King’s College London in the late 19^th Century. The Maxwell Equations are four equations which link the fundamental behaviour of electric and magnetic fields.

   Electromagnetic fields and waves, including light, are essential in modern technologies providing internet, mobile phones, lasers. In the quest for ever smaller and energy-efficient devices, researchers study the interaction of electromagnetic waves with nanostructures.

   As the spaces being studied are so small, often smaller than the wavelength of light or ‘sub-wavelength’, several new parameters of light waves become crucial, such as light polarisation, which define the spin of light.

   Following in Maxwell’s footsteps, a team of LCN researchers at the Physics Department, King’s College London, in collaboration with Shenzhen University in China, have developed the set of equations for spin and momentum of the electromagnetic field, which are analogous to the Maxwell’s equations.  This new set of equations allow a direct understanding of spin properties without the explicit knowledge of the electromagnetic field.

   

   In analogy to renown effects in condensed matter physics, photonic quantum spin-Hall effect and photonic skyrmions require careful description of spin properties of light waves, which is possible with Maxwell’s equations, but the derivations are lengthy and cumbersome.

   Using the newly developed equations, the team has now demonstrated the unconventional spin properties of the electromagnetic waves carrying orbital angular momentum, important for optical communications, quantum technologies, high-resolution imaging and many other fields.

   The new equations offer a shortcut for describing the unconventional spin behaviour of the electromagnetic waves, and can be applied to describe also fluid, acoustic and gravitational waves.

   Using this approach, it is very easy to see new, unexpected phenomena in the electromagnetic spin behaviour. For example, we predicted and experimentally observed dynamic behaviour of the transverse spin of guided waves arising due to spin-orbit coupling, which has completely different behaviour from the static transverse spin of evanescent plane waves.

   Professor Anatoly Zayats, Head of Photonics & Nanotechnology Group, King’s College London

   Transverse spin dynamics in structured electromagnetic guided waves is published in Proceedings of the National Academy of Sciences of the United States of America.

5. Quantum circuits with a levitated heart

   December 11, 2020 4:15 pm Leave a Comment

   A collaboration between London Light researchers and the University of Duissburg-Essen has found a way to strengthen quantum networks by levitating key components, whilst simultaneously exploring the boundaries of quantum mechanics. 

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   Do you believe in quantum physics? Quantum theory is the unchallenged description of the microscopic realm, yet seemingly has little impact on the world around us. While it is possible for photons or electrons to “be in two places at once”, known as quantum superposition, the chair you’re sitting on displays a stubborn refusal to play quantum ball. 

   
   There are good reasons why it’s hard to make big objects behave in a quantum way; quantum mechanics requires exquisite isolation to manifest its stranger behaviours. The bigger something is, the harder it is to isolate. In his lab at King’s, Dr. James Millen uses light and electrical fields to levitate microparticles in a vacuum, achieving the required isolation from the environment. Although they sound tiny, microparticles are more than a thousand times larger than the current largest quantum objects, and much larger than components used in modern electronics. 
   

   We do exploit quantum physics in technology, with companies like Google and IBM building quantum computers using tiny electrical quantum systems called qubits. The lead author on this collaborative project, Lukas Martinetz from the University of Duisburg-Essen, found a way to connect qubits and levitated microparticles, sharing their quantum behaviour with the otherwise non-quantum particles. 

   
   By working with charged microparticles, their motion can be detected and effected by nearby electrical circuitry. The team considers interfacing a charge quibit, meaning that the voltage in the circuit can be in a quantum superposition. This voltage will exert a force on the levitated microparticle, pushing it into a superposition of positions. By introducing the levitated object, the utility of the quantum circuit is greatly enhanced. Delicate quantum information can be stored in the motion of the particle, and shared between other distant qubits, building a robust quantum network. This will boost the usefulness of quantum computers, and help us build a quantum internet.
   Observing a micro-scale object in a quantum superposition would extend the reach of quantum theory into the world around us. In the future, this could be used to understand the interaction between quantum physics and gravity, one of today’s greatest scientific challenges.

   
   Quantum electromechanics with levitated nanoparticles is published in NPJ Quantum Information
   This work is supported by EPSRC New Investigator Award EP/S004777/1 and ERC Starting Grant 803277.
   

6. London Light on YouTube

   November 11, 2020 3:39 pm Leave a Comment

   The London Institute for Advanced Light Technologies now has a YouTube channel. We will be posting talks from our members, and videos of our events.

   Our first video ‘Generating colour 3D images from planar metasurfaces’ is from Dr Diane Roth from the Department of Physics at King’s College London.

   Diane is a member of the Photonics & Nanotechnology Group lead by London Light co-director Professor Anatoly Zayats.

   Her research interests are:
   •    Control of light-matter interactions with nanostructures and metamaterials.
   •    Application of plasmonic metasurfaces and structured light for optical communications, displays, security, biochemical sensing and optical trapping.
   •    Experimental verifications of fundamental physical phenomena at the nanoscale,
   •    Development and implementation of techniques for optical characterisation e.g. spectrally-resolved Fourier microscopy, complex vector beam shaping, time-resolved photoluminescence spectroscopy.

7. London Light researchers make electrical nanolasers even smaller

   October 20, 2020 4:09 pm Leave a Comment

   London Light researchers at King’s College London, in collaboration with a team at Moscow Institute of Physics and Technology have developed a concept of an electrically driven nanolaser which is not only much smaller than the other integrated lasers but even smaller than the free-space wavelength it is emitting.  The Nano-Optics group at King’s College London, led by Professor Anatoly Zayats, have previously reported on nanoscale electro-optical modulators and together these nanodevices will mark a milestone in the development of fully functional highly-integrated optoelectronic circuits for optical data communication. 

   Once incorporated into electronic computational chips, such circuitry will revolutionise on-chip data transfer, substituting ‘slow’ and lossy metallic wiring overheating the chip with broadband and energy-efficient optical network. This means that the best technology for data communication (photonics) will be merged with the best technology for data processing (electronic), leading to hybrid electronic/photonic chip architecture with superior computational power.

   Nanolasers have been at the edge of nanophotonic research of the last decade. However, the vast majority of the proposed designs utilise optical pumping schemes, requiring high-power ‘ordinary’ external lasers, which makes their practical application challenging. Electrically-pumped nanoscale counterparts met a fundamental problem when the Ti- or Cr-based low-resistance contact required to supply the electrical pumping to the optical mode simultaneously did precisely the opposite introducing unacceptable losses related to the optical absorption in the metals. The researchers have now solved this problem by proposing a novel electrical pumping scheme based on a tunnelling Schottky contact, which gets rid of highly-absorbing materials and supplies the electrical power with no loss penalties. Furthermore, the contact simultaneously confines the nanoscale optical mode in the form of surface plasmon polaritons in its vicinity – precisely in the region of most efficient amplification. Importantly, the nanolaser operates at room temperature and emits light directly into an optical waveguide, which makes it easy to integrate it into the optoelectronic circuitry. Despite the nanoscale dimensions the emitted optical power of a single nanolaser is high enough to transmit 100s of Gb/s of data, matching record-high data speeds.

   The article ‘Lasing at the nanoscale: coherent emission of surface plasmons by an electrically driven nanolaser’ was published in Nanophotonics 

   This work was funded in part by the EPSRC programme grant Reactive Plasmonics

   

   Image credit – Electrically pumped surface plasmon-polariton nanolaser – Dmitry Fedyanin

8. Future Horizons for Photonics Research 2030 and beyond report released

   September 7, 2020 12:11 pm Leave a Comment

   A ground breaking horizon scanning report on the future of photonics research 2030 and beyond has been released by the Photonics Leadership Group and the All-Party Parliamentary Group in Photonics and Quantum.  The PLG brought together 26 of the UK’s leading photonics researchers from 20 different institutions to ask “what will be the focus of photonics research a decade and more from now?”

   View the report here 

   Recognising all R&D takes place in an ever developing socio-economic environment, the report also identifies nine major challenges that photonics will have a key role in addressing. Ranging from future mobility, healthy-aging and real-time secure communications to responsive manufacturing, food production and defence; it is clear that photonics not only already makes a major contribution to society, but will be absolutely instrumental in addressing the challenges of the future.

   The report makes 7 clear recommendations to translate the identified topics into funded research balanced across all domains.  The recommendations also call on those working in vertical markets to integrate this future vision into their technology roadmaps to ensure the very best and most advance photonics is rapidly pulled through into applications for the benefit of all.

   Described by some of the UK’s leading photonics researchers as “an excellent and timely report” capturing how much  “it is an exciting time for the field”, it is hoped the highlighted topics stimulate discussion on the future directions for photonics as well as inspire the next generation of researchers.

   Co-director of London Light Anatoly Zayats said “It is very important for the photonics community to have a global view of the challenges, trends and needs of photonic science and technology in the years to come. We hope very much the document will provide the government and industry with understanding where photonics goes and its role in the future of our society.”

   John Lincoln, Chief Executive of the PLG said “It has been an incredible cathartic and inspirational exercise to take a break from all of our current challenges and look to the future and consider the huge diversity of photonics still to be discovered.”

9. Generating colour 3D images with designed reflective metasurfaces under incoherent illumination

   May 20, 2020 4:22 pm Leave a Comment

   As part of an international collaboration with Southern University of Science and Technology in Shenzhen (China), LCN researchers at King’s College London have developed a novel way of generating colour 3D images using a reflective metasurface performing through the entire visible spectral range. Metasurfaces are 2D engineered materials typically made of subwavelength elements, which provide excellent control over the shaping of optical wavefronts via the manipulation of polarisation, phase and amplitude of the light. Unlike typical metasurface-based holography techniques, the developed method does not rely on interleaved nanostructures for wavelength multiplexing or wavelength-dependent off-axis illumination. Instead, the LCN researchers used specially-designed aluminium nanostructures to achieve a high metasurface efficiency across the visible spectrum, including the three main RGB colours. A combination of specular and diffuse reflections was employed to generate images of 2D structures with 3D effects. The true perception of a 3D object through shading effects is therefore ensured by an adequate change in the brightness of the reflected light from the flat metasurface in response to variations in the illumination or observation angle. In contrast with 3D holograms, this structure performs under incoherent illumination.

   As a proof of concept, an image of a 3D cube was encoded onto the metasurface and illuminated with white light. The projected image displays shading effects changing according to the incident angle, therefore emulating the behaviour of a real 3D cube. 

   The lead author on the paper published in the journal Nano Letters, Dr Diane Roth said, “Metasurfaces are extremely versatile and have the potential to enable progress in many different areas of science, either introducing new functionalities or making existing technology smaller and lighter. The practical potential of our design is very interesting for a wide range of applications including security features for protection against counterfeiting but also artistic purposes.” More generally, the unique properties of diffuse metasurfaces could also have an impact on the development of new display technologies, flat light diffusers and integrated optical components.

   

   
   Results from this international project have been published in the American Chemical Society journal Nano Letters.

   
   Link to article in Nano Letters: 3D full-colour image projection based on reflective metasurfaces under incoherent illumination

10. What is on the Horizon for Future Photonics Research

    April 30, 2020 11:37 am Leave a Comment

    The Photonics Leadership Group have published the preliminary outputs of a recent workshop that comprised of twenty-five of the leading photonics researchers in the UK.

    The academics were asked ‘What is on the Horizon for Future Photonics Research?’ to generate a picture of where photonics research will be focused in ten years time. The raw output of that workshop is captured in the summary of seventy topics identified as offering significant potential for future investigation (shown below).

    The detailed outputs will be published in a full report in the summer of 2020.

    You can read more on the Photonics Leadership Group webpage.

    

    Click to see full-sized image