Novel photonic devices for optical neural networks

The project will start by developing a single pixel as the fundamental building block of an optical neural network system. The pixel will consist of a grating structure supporting a guided mode resonance that acts as a reflector. By realising the grating in an electro-optically tunable material such as Indium Tin Oxide (ITO), the reflectivity can be controlled electrically. The particular challenge is to control the material parameters using our in-house sputtering system and design the device structure such that either the amplitude or the phase of the beam can be modulated. Here, the student will benefit from the body of existing work on guided mode resonances developed for sensing applications; for example, we are now able to detect refractive index changes of Dn<10-5, which means that similarly small electro-optically induced index changes will lead to a noticeable modulation of the beam, opening the prospect for low-power and high-speed operation.

The project incorporates design and simulation, materials research and fabrication as well as structural and optical characterisation, which gives the student the satisfaction of being in charge of all relevant elements of their research. The student will be part of a vibrant interdisciplinary team and be exposed to a range of related research areas offering exciting cross-fertilisation opportunities regarding materials, devices (incl. modelling), nanofabrication and applications. They will also be exposed to industrial reality through our regular meetings with Optalysys, a local SME who are commercialising a similar optical neural network system.