Novel non-linear materials for photonics - an investigation into metals

A large array of applications ranging from optical coatings, plasmonic antenna, metasurfaces, high resolution imaging, biosensors to integrated photodetectors and modulators would benefit from active tunable optical properties of metallic thin films and nanostructures. Existing technologies to achieve active tunability either by incorporating tunable electro-optical materials, laser post-processing or electrolyte gating, are limited to low speed, irreversible or low energy efficiency. Although the phase transition of metals between amorphous and crystalline structure have been studied since 1960s, there have been no reports of single elemental metals having an actively tunable optical property. Indeed, even electronically, it was only recently amorphous states of single element metals have been obtained by nanosecond (ns) electrical pulse melt-quenching.

In this project we will take our recent work on such materials in optics and investigate how the materials behave on integrated optics, the dynamic behaviour of these materials and their potential suitability in their various structural states for use as non-linear materials. Their optoelectronic properties will also be investigated in detail and their use as plasmonic materials will also be explored.

These are extremely novel areas of research and the use of metals as tunable optical materials has only been recently elucidated by our research. Thus the field is nascent and will benefit from further investigation, just as integrated photonic comouting is becoming mainstream. Alloys have issues with segregation over many cycles of operation, and thus monoatomic metals have distinct advantages in technologies of the future, such as AI and Machine Learning hardware.

This project falls within the EPSRC Physical Sciences and ICT research area. We will collaborate with Exeter University, Munster University as well as with other departments in Engineering Science at oxford in order to progress this work. We will leverage our existing relationships with IBM, Microsoft etc. also.