In this work, published in Scientific Reports, we describe a conformable holographic metasurface operating in the visible range. We use gold nanoantennas to point-by-point tailor the Berry phase of a flexible membrane to create high fidelity images with helicity multiplexing. These membranes can then be applied to substrates which could not be nanopatterned directly. We demonstrate this experimentally with a glasses lens. The full article can be found here
As always at this time of year, PhD student assessments take place. The 2nd years must give a 15 minute talk on their research area. Adam Fleming, Alasdair Fikouras, James Burch, and Xin Li from the Synthetic Optics Group all gave very well received talks. For the 2nd year in a row, a member of the Synthetic Optics Group has won the Arthur Maitland Prize for best talk. Congratulations to Alasdair Fikouras, for his talk titled “Biolasers: Photonic Nano-Disk Resonators for Intracellular Exploration.” Congratulations to James Burch also, who came 3rd, for his talk titled “Conformable Holographic Metasurfaces”
The Synthetic Optic Group recently went on their annual “Away Day” to the Grandtully area in Fife. Everyone involved gave some fascinating talks on the future direction of their research, cooked mostly good food, and then got thoroughly soaked white water rafting. (Apart from myself haha!) SYNTHRAFT!
Congratulations to the venerable Blair Kirkpatrick, who passed his PhD viva in March. Blair was the second PhD student to join the Synthetic Optics group, and thankfully his special brand of humour will not be leaving us quite yet, as he will be doing a Post-Doc within the Synthetic Optics Group
In a paper published in Appl. Phys. Lett., we report the first measurements of optothermal nonlinearity of silica aerogels. Silica based aerogels are ultra porous materials with refractive index close to unity. Their extreme porosity is responsible for very low thermal conductivity, which in turn leads to very peculiar optothermal properties. In this paper, in collaboration with researchers at the University Sapienza and CNR, we measured the optothermal nonlinear coefficient of silica based aerogels in the visible range. The full article can be found here.
In a paper published in Phys. Rev. Lett., we experimentally demonstrate that the distribution of phase singularities in vectorial random light fields is anisotropic. Our collaborators at AMOLF, led by Prof. Kobus Kuipers, have measured the distribution of phase singularities supported by a chaotic electromagnetic landscape, reading the surface of a photonic crystal (PhC) cavity with a SNOM. PhC chaotic resonators in silicon on insulator technology are an ideal platform to prepare a random field with repeatable and well defined characteristics. Exploiting this feature, we were able to track the deep-subwavelength phase singularities supported in the cavity. Our results demonstrate that, due to the… Read More »Spatial Distribution of Phase Singularities in Optical Random Vector Waves
Our work on the “Optically Induced Metal-to-Dielectric Transition in Epsilon-Near-Zero Metamaterials” has recently appeared in Scientific Reports. In this work we designed a metamaterial with epsilon-near-zero (ENZ) response, that is tuned all-optically from a metallic to dielectric behaviour. The transition is demonstrated using an ultrafast pump and probe scheme. The study unveils both analytically and experimentally the full associated nonlinear dynamics. The full article can be found here.
In collaboration with Heriot-Watt University and Purdue University, we published a paper in Phys. Rev. Lett. demonstrating that epsilon-near-zero metamaterials (ENZ) exhibit an enhanced nonlinear response. In this study we demonstrated a six-fold enhancement of the Kerr nonlinear refractive index in proximity of the ENZ condition, in the near-infrared. The experiemtn was performed on Al-doped ZnO (AZO) thin film, and demonstrates a general behaviour of ENZ materials. The full paper can be found here.
In this work, published in Laser Photonics Review we report on the all-optical control of chaotic optical resonators based on a silicon on insulator (SOI) platform. We show that simple non-chaotic cavities can be tuned to exhibit chaotic behaviour via intense optical pumping, inducing a local change of refractive index. To this extent we have fabricated a number of devices and demonstrated experimentally and theoretically that chaos can be triggered on demand on an optical chip. We show that the degree of chaos supported by a microcavity can be controlled dynamically using light itself. We start with a square (non-chaotic) cavity obtained on SOI.… Read More »Ultrafast All-Optical Order-to-Chaos Transition in Silicon Photonic Crystal Chips
Congratulations to James, who has won the runner up prize for the Poster competition at the 12th International Symposium on Photonic and Electromagnetic Crystal Structures (PECS-XII), taking place at University of York in July 2016. His Poster on “Flexible Broadband Metasurface Holograms” was chosen by a panel of judges from a selection of nearly 40 participating entries.