Deep ultraviolet LED devices for few-photon optical communications and imaging

The Institute of Photonics is a recognized international pioneer of micro-LEDs, arrays of micron-sized light-emitting diodes constituting a new high-brightness microdisplay and backlighting technology - being applied, for example, to advanced virtual and augmented reality headsets. These displays interface to CMOS electronics and can be modulated at very high (megahertz) frame rates and communicate data at gigabits/second. Such rapidly modulated patterned light enables a form of optical projection called structured illumination with applications in indoor navigation, spatially modulated data communications, single pixel imaging and bio-imaging. These GaN microdisplays are extremely energy efficient and can be run with ultra-low photon flux. By coupling these displays with high speed single photon avalanche detector (SPAD) arrays, we have demonstrated a unique method for the spatio-temporal encoding of information at the few photon level that is extremely robust to noise. Initial demonstrations of simple data transmission, with efficiencies in the order of 30 photons per bit, have already garnered significant interest from the scientific and industrial communities.

This project will develop novel formats of these devices operating at deep ultraviolet wavelengths (<280nm). At these wavelengths, the earth's atmosphere is highly scattering and opaque to solar radiation. This offers the possibility of 'communicating around corners' at very low light levels or communicating between satellites at wavelengths that cannot be seen from the ground. It also offers novel forms of microscopy system with high resolution and sensitivity to surfaces and interfaces. The project will encompass optical systems design and development, electronic driver and software coding and sparse data signal processing techniques. The PhD student will have access to state-of-the-art, custom LED and SPAD array devices, optical characterisation facilities and software tools, and will contribute to the UK's national programme on Quantum Technologies.