Quantum Topological Polaritonics

ended

The recently proposed idea of topological band classification in photonic crystals has led to the prediction and observation of topologically nontrivial photonic phases, phenomenologically similar to Quantum Hall and Quantum Spin Hall electronic phases, and to the development of a new field in physics – topological photonics. Photons at the edges of topologically nontrivial photonic crystals are protected from backscattering and can be used for unidirectional guiding of light, which is extremely promising for optical logical device applications and for future optical computers. These ideas have recently given a new dimension to the field of polaritonics, which is the semiconductor optics equivalent of cavity quantum electrodynamics, where bound electron-hole pairs, or excitons, are strongly coupled to cavity photons to give rise to interacting quasiparticles: polaritons. Topological polaritonic states were shown to emerge in nanostructured microcavities solely from polariton repulsive interactions and can be controlled by optical means, contrary to the purely photonic case. In contrast to electronic and photonic topological physics, quantum topological polaritonics combines strong nonlinear and non-Hermitian quantum effects that remain to be explored. This project will provide the fundamental theory basis for quantum topological polaritonics, a new emerging field that unites topological photonics with polaritonics. The applicant, in collaboration with the host group, will develop the geometric theory and the topological classification of polaritonic states, accounting for their strongly nonlinear and non-Hermitian nature. He will also apply this theory to the experimentally studied polaritonic systems with potential impact on optical devices of the future.