We would like to thank Henry for his work as SAG member over the past couple of years – and send a very warm welcome to Joe.
SAG consists of normally 2 members of each cohort who represent the student body at meetings with the Management and Oversight Boards. They help to implement new ideas that benefit the overall experience of their peers, to offer different perspectives, and to ensure the PGRs’ opinions are heard. SAG is currently chaired by Ben Hogan.
On 16 May 2018 the world saw the celebration of the first ever International Day of Light. The event was celebrated around the world with more than 500 events taking place in 87 countries to create awareness of the role of light plays in science, culture and art, education, and sustainable development, and in fields as diverse as medicine, communications, and energy.
Why May 16th?
The International Day of Light is a global initiative that provides an annual focal point for the continued appreciation of light in all forms and shapes and applications. It will be held on May 16th every year, the anniversary of the first successful operation of the laser in 1960 by physicist and engineer, Theodore Maiman.
The Optics and Photonics Society of the University of Exeter (EUOPS) did not wanted to miss this opportunity to join the worldwide celebration and organised events open to the entire community of Exeter. They held a photo competition with three main categories, which encouraged participants to showcase how important light is nature, in their day-to-day life and in technology. Bill Barnes, Professor of Photonics at the University of Exeter, had the difficult task to choose the winners among the 57 photo submissions:
Pak Hin Fung won the “Light in Nature” category with a beautiful photo of one of the most touristic places of Exeter: The Quay. In Bill’s words: “It seems at first that this is a picture of buildings etc., but if one looks for a little while it becomes clear that the sky, and its reflection, wins“.
The “Light in Technology” first place went to Adolfo De Sanctis with his photo about waveguides and fluorescence: “Guiding of light is so important to our digital age. It is nice to see this simple demonstration of how light is guided to the edge of the slide to remind us that it is really a simple phenomenon”.
Finally, the first place of the “Light in Day-to-Day Life” category and the overall winner of the competition was the photo by Flo Pearson titled “Peg Shadows”: “This picture is really made by the shadows of the pegs – an absence of light!“
Alongside the photo competition, there was a poster competition where the participants were asked to explain to the general public how they use light in their research. There was one simple rule: explain your research in the easiest way possible. The 5 poster submissions were judged by year 12 students (Adam Barber, Peter Betts, Harry Price) and their teacher Dr Aude Alapini-Odunlade from Clyst Vale Community College.
The winner of the poster competition was our very own XM² 4th year PGR Christopher King with his poster explaining the designing of non-scattering material, which can be the base for invisible materials.
Between these two competitions, £300 in prizes were shared between firsts, seconds, and audience favourite prizes,. The award ceremony was held in the Forum of the University of Exeteron 11th of May.
A very special thanks goes to EUOPS and the XM² 4th year PGR Erick Burgos Parra who organised an outstanding first celebration of the International Day of Light!
Photo competition winners in order of appearance in the text above:
When coherent light (like a laser) passes through or reflects off most materials, it scatters and creates what is known as a speckle pattern, a seemingly random intensity pattern. These speckles limit the precision of many types of imaging applications, including microscopic images of biological processes and ground-based telescopic views of space. Common sense suggests that reflected and transmitted light are completely uncorrelated—no information can be obtained regarding the transmitted light by measuring the reflected one and vice versa. However, some of our team recently predicted that interference effects should lead to such correlations. We experimentally investigate this prediction, and we find that this correlation not only exists but is much richer and more complicated than expected.We shine a helium-neon laser at a 45-degree angle onto a slab of glycerol with suspended particles of titanium dioxide and look for correlations between the speckle patterns of the transmitted and reflected light. By exploring a large range of sample thicknesses and scattering mean-free paths, we show that for large optical densities, the reflected and transmitted intensity profiles exhibit a long-range anticorrelation. For thinner systems, this is accompanied by a previously unforeseen long-range positive correlation. We develop a perturbative theory that describes both contributions and accurately represents the experimental results.The presence of correlations between the reflected and transmitted light proves that information of what is happening on the far side of an opaque medium can, in principle, be obtained by only measuring reflected light, thus opening the way to novel noninvasive imaging techniques.
The work demonstrates how phase-change materials can be used in conjunction with periodic hole arrays to manipulate the extraordinary optical transmission phenomenon to create ultra-thin, high performance, tunable band-pass filters. These filters are applied to the role of multispectral imaging and biological sensing.
Very many congratulations to Tanveer Ahmad Tabish who successfully defended his PhD in May 2018. His thesis is titled “DEVELOPMENT OF GRAPHENE NANOSTRUCTURES FOR USE IN ANTI-CANCER NANOMEDICINE”, and has been supervised by Shaowei Zhang and Yongde Xia.
Four PGR students from Exeter’s CDT in Metamaterials travelled to Strasbourg to present their work at SPIE Europe, the only cross-disciplinary optics and photonics event in Europe.
The conference covers topics across the most significant photonics technologies—from digital optics to quantum technologies to attosecond science. 2018 saw the addition of 7 new conference topics being covered at the conference, including Advances in Ultrafast Condensed Phase Physics, Unconventional Optical Imaging, 3D Printed Optics and Silicon Photonics.
Our PGRs Alba Paniagua Diaz (“Enhanced deep detection of light for Raman spectroscopy by wavefront shaping“) and Illia Starshynov gave talks on their respective work, and Kieran Walsh (“Wafer scale FeCl3 intercalated graphene electrodes for photovoltaic applications“) and Iago Rodriguez Diez (“Visible Light Emitting Waveguide on Silicon Chip, based on Polymeric Quantum Dots”) presented posters of their most recent research.
We have theoretically and experimentally demonstrated a Fabry-Pérot (FP) resonators based on a Si-air one-dimensional photonic crystal (1D PhC) with coupled triple-cavity modes (or defects). These defects are obtained by filling selected air channels in the 1D PhC with an actively reconfigurable fluid. Simulations of the optical properties of these FP resonators were performed in the wide infrared spectral range. It is shown that by changing the refractive index, nc, of the fluid simultaneously in all three channels, a set of narrow triple resonance peaks can be obtained within wide stop-bands of different order in the infrared range. In addition, at certain values of nc, splitting of the triple resonance peaks into a doublet and a single peak with a significantly larger quality factor, Q = 21,200, occurs. Prototype devices based on Silicon-On-Insulator platform were fabricated and characterized by electro-optical and spectroscopic measurements. The electro-optical measurements demonstrate the possibility of refractive index manipulation of the filler in the FP channels individually or simultaneously. Spectroscopic measurements performed in the range 1540–1630 nm using fiber-coupling confirm the presence of triple resonance peaks in the 3rd stop-band in the absence of an electric field applied to the FP channels. At an applied voltage of 10 V to the middle channel, an increase of Q to 3720 in the single peak is registered.
£15,000 were recently awarded by the ChAMP / WAFT Collaboration Fund to the Physical Chemistry group at Cambridge and researchers at the University at Exeter.
The CDT in Metamaterials PGR Liam Trimby contributed significantly to the development of this proposal, following an idea from Dr A Alexeev to demonstrate a novel approach for chemical sensing based on phase-change IR metamaterial devices, and to use the preliminary results to submit a larger collaborative grant application.
Both the ChAMP and WAFT research projects are funded by EPSRC and work with a number of academic and industrial partners. Synergies between the projects have developed joint funding of PhD student/post-doc led proposals for collaborative research across ChAMP and WAFT.
This project will last from 1-June-2018 to 30-September-2018 and bring together a team from Engineering at the University of Exeter
Liam Trimby – PhD candidate at the EPSRC Centre for Doctoral Training in Metamaterials
Dr Arseny Alexeev – Honorary Research Fellow with 8 years’ experience in nanophotonic devices
Prof David Wright – Leader of Nanoengineering Science and Technology Group, Department of Engineering
and a team from Physical Chemistry at the University of Cambridge
Farah Alimagham – PhD candidate in optical chemical sensors, spectroscopy and microfluidic systems
Dr Tanya Hutter – Research Fellow with 8 years’ experience in chemical sensor development
Prof Stephen Elliott – Leader of Chemical Physics Group at the Department of Chemistry.