Chalcogenide Photonic Technologies

Chalcogenides are materials based on metallic alloys of sulphur, selenium and/or tellurium. Although only formed into glasses for the first time in the 1950's, they emerged first in a new generation of CD's and DVD's where their ability to be formed into glass and crystalline structures allow information to be stored. This optical storage is based on changes of optical properties when a laser heats the chalcogenide material and converts it from crystalline to glass structure. This phase change effect is also being actively investigated for electronic memories ultimately aiming to replace present memory stick technology. Chalcogenides here offer vastly higher read and write rates, smaller memory cell size and improved stability over time.

In the proposed work, we are aiming to develop further optoelectronic applications of chalcogenides by exploiting and enhancing our expertise in depositing thin films of chalcogenide and subsequently forming light guides in these films. The confinement of light in the guides will enhance the guided light power and could lead to devices based on phase change as above. However the chalcogenides have much faster and stronger responses to light, which can be engineered to be extremely effective through the waveguide structure allowing us to develop ultra-high speed optical switch elements, devices for converting between light wavelengths (changing the 'colour') and quantum light sources emitting photons in 'spookily connected' entangled pairs . By doping our waveguides with transition metals we expect to make lasers at a significant number of new wavelengths, particularly in the infrared region. Chalcogenide glass has higher transmission at much longer wavelengths than conventional glasses extending the laser applications to eyesafe rangefinders for aerospace, chemical sensing and specialist medical sensors.

Chalcogenides are one of the most active next generation material technogies now being developed. They revolutionized optical data storage through their use as a phase change memory material and are set to revolutionize electronic memory. Their dispersive nonlinearities, essential for high speed optical switching are higher than silicon and their recent realization in 2D layers, in forms such as molybdenum sulphide, suggest they provide a strong rival to graphene for electronic applications. This project represents a formal start to an existing collaboration between Bristol and Southampton and a commitment to expand the functionality of chalcogenides in photonics in order to provide impact at even more levels.

The proposal addresses an area of significant national importance and addresses several EPSRC priorities in Advanced Materials, Photonics for Future Systems, Towards an Intelligent Information Infrastructure, Quantum Technology hubs and physics grand challenges: Quantum Physics for new Quantum Technologies and Nanoscale Design of Functional Materials.
Our proposal will make a significant contribution to the training of two mid-career post-doctoral researchers, Dr Chung-Che Huang (ORC) and Dr Ying-Lung Ho (Bristol), who initiated our collaboration, made their significant contribution to writing the proposal, manage workpackages and co-supervise students. They will be mentored by Professors Hewak and Rarity. Other post-doctoral students and PhD students working in related areas will also benefit. We will support neighbouring Eastleigh College in training apprentice technicians.
Our proposal compliments that of several research groups in the UK and our results will feed into and the strengthen the UK foundation in this area. Quantum relevant results will be fed to quantum technology hubs on reaching sufficient technical maturity.

We will disseminate our results in high-impact journals and will present this interdisciplinary work at a wide range of conferences such as (E-)MRS (materials), CLEO and LEOS (optoelectronics), Semicon West and EPCOS (electronics), SPIE Photonics West (opto-semiconductors) and ICANS (amorphous semiconductors).
Results of the research will be exploited through the Research and Innovation Services (R&IS) group (ORC) and the Research & Enterprise Development Office (Bristol). We aim for the first technological outputs of this programme to demonstrate commercial potential by the end of the project and would look for routes to bring successful work to market. To this end we will focus on strengthening our links with future exploiters including our previous licensees: Ilika Technologies Ltd, Southampton Photonics (now SPI Lasers), and Bristol start ups QUMET Technologies (Bristol) and Venture Photonics. We will also pursue entrepreneurial and start-up activity with Set Squared, and the Bristol based Engine Shed 'hot house'.