Exciton-polariton physics

The Polariton BEC group is engaged in theoretical and experimental research on Bose-Einstein condensation (BEC) of exciton polaritons in semiconductor microcavities. We investigate quantum phenomena far from equilibrium and their applications for next-generation optoelectronics devices.

Currently, the group is pursuing research in the following directions:

  • Non-Hermitian quantum physics of exciton-polaritons
  • Ultrafast transient dynamics of spontaneous condensation
  • Exciton-polarioton condensatiion in periodic "superlattices"
  • Strong light-matter coupling in novel atomically thin materials

Excitation-polariton BEC

Polaritons are bosonic composite particles that are part light and part matter. They are composed of photons and excitons (electron/hole pairs) forming in semiconductor microcavities in the strong light-matter interaction regime. Akin to ultracold neutral bosonic atoms, polaritons can undergo Bose-Einstein condensation. In a Bose-Einstein condensate (BEC), millions of bosons occupy a single quantum state and display collective quantum behaviour, such as superfluidity.

A BEC is one of the most sensitive and controllable quantum systems. It has applications ranging from precision measurement sensors and metrology standards, through to tests of the fundamentals of quantum mechanics. The polariton BEC bears many similarities to the BEC of neutral atoms, which exists at temperatures within a millionth of a degree of absolute zero. In contrast, a polariton BEC forms at both cryogenic and room temperatures in a solid state. Observation of the first polariton BEC in 2006 has prompted the emergence of polaritonics – a new science that studies collective quantum effects in semiconductors.

Polaritonics in the flatland

Novel atomically thin transition metal dichalcogenides (TMDs) represent a perfect 2D "flatland" platform for creating excitons with large binding energies and coupling them to light. The large binding energies could potentially lead to room-temperature condensation in these very clean and versatile materials. In our group, we aim to design, fabricate, and spectroscopically interrogate TMD-based microcavities and progress towards Bose-Einstein condensation of exciton polaritons in this structures. The excitement in the field comes from the possibility to observe dissipationless (superfluid) exciton-polariton transport at room temperature using the new 2D material platform.

This research effort is part of the ARC Centre of Excellence for Future Low-Energy Electronics Technology (FLEET).

Updated:  30 November 2021/ Responsible Officer:  Head of Department/ Page Contact:  Physics Webmaster