Exciton polaritons in synthetic fields
A PhD scholarship opportunity is open to work on experimental physics of exciton polaritons in synthetic fields.
Exciton-polaritons are part-light part-matter particles arising from the strong mixing of photons in a photonic cavity and excitons in a semiconductor. The hybrid nature of these particles enables the formation of Bose-Einstein condensates (BEC) and superfluids at room temperature, a promising step towards realising applications of macroscopically coherent quantum states at ambient conditions. However, there are two hurdles on the way towards this goal: (1) charge neutrality and (2) inherent photonic losses. The former makes exciton-polaritons interact weakly with external electromagnetic fields while the latter makes the particles extremely short-lived.
In this project, we aim to tackle the first and take advantage of the second issue by inducing synthetic fields that mimic the strong effects of real electromagnetic fields on exciton-polariton condensates and superfluids. By building on the breakthroughs in photonics, such as metasurfaces, non-Hermitian photonics, and chiral optics, we will engineer the cavity photon to create strong and nontrivial artificial fields for exciton-polaritons.
As a PhD student, you will be involved in the following:
- numerical modelling,
- fabrication of samples, and/or
- optical experiments.
Polariton Bose-Einstein Condensation for Future Devices
The aim of this project is to investigate the applied properties of polariton BEC and thereby accelerate the development of the next generation of quantum and optoelectronic devices. The potential impact of a BEC in a solid state material for harnessing novel collective quantum effects for future applications of optoelectronics and precision sensors is substantial. Quantum physics has had a huge impact on modern society, it has been responsible for the transistor, laser, and Magnetic Resonance Imaging (MRI) to name but a few critical technologies.
The hybrid light-matter properties of polaritons makes them particularly appealing for integration into optoelectronic devices. The merging of polaritons and optoelectronics into a single device is so promising that it has spawned the new field of polaritonics. Polaritonics has the capability to enhance existing optoelectronic devices and to enable next generation optoelectronic devices including integrated optical circuits, classical and quantum logic elements, optical switches, and spin-memory elements.
The applied properties of polariton BEC that this project will specifically investigate include manipulation of polaritons using external potentials and spin dynamics. During the project the student will develop skills in the following areas:
- Optics and lasers
- Femtosecond imaging and single particle detection
- Material science
- Data analysis
- Experiment automation
Fundamental experimental studies with polariton Bose-Einstein condensates
The hybrid matter-light nature of polariton BECs make them ideally suited to fundamental investigations. The important fundamental problems that this project will investigate include non-equilibrium dynamics and polariton BEC coherence.
The concept that a BEC can form in a solid state material with reduced dimensionality is remarkable. It is the aim of this project is to systematically investigate polariton BEC coherence including its onset and ubsequent time evolution. Moreover, we aim to investigate how the polariton BEC coherence is influenced by non-equilibrium dynamics, trap geometry, pumping, and losses.
The fundamental understanding of non-equilibrium systems had been recognised a one of the grand challenges in physics today. Due to the inherently open-dissipative nature of the polariton BEC system, it is an excellent platform for non-equilibrium studies. This project will investigate collective behaviour of polariton condensates in structured microcavities and their manipulation by optical pumping.