Physikalische Chemie - Direktor: Prof. Dr. Martin Wolf
Department Online Seminar
Chair: Sebastian Mährlein

Thursday, October 15, 2020, 3:00 pm
Michael Scott Spencer
Columbia University
Anisotropic Exciton-Polaritons in Lead Halide Perovskite Optical Cavities
Exciton-polariton systems are increasingly being pursued for their capability to provide experimental realizations of novel Hamiltonians,[1] in addition to their traditional attraction of high-temperature Bose-Einstein condensation emission states.[2] I will share results of Lead Halide Perovskite CsPbBr3 as an excitonic-polariton material in an optical cavity, where there are dramatic implications for the polariton dispersion, derived from the crystalline anisotropy. The broken cylindrical symmetry of the photonic field leads to a splitting of the photon rest mass, lifting the degeneracy of the photonic spin states.[3] The competition between the aforementioned effect of crystalline anisotropy and the traditional TE-TM splitting mechanism [4] provides rich spin texture physics which are experimentally investigated. This investigation is carried out using a home-built polarization-resolved fourier-plane imaging spectrometer, allowing for measurement of the full polarization state for all wavelengths and photon momenta. In this way, it may be verified that the model Hamiltonian is responsible for the measured dispersion. The implications of this Hamiltonian, and further experimental investigations will also be discussed. [5]
[1] Whittaker et al., ‘Exciton Polaritons in a Two-Dimensional Lieb Lattice with Spin-Orbit Coupling’, Physical Review Letters, 2018
[2] Deng et al., ‘Exciton-polariton Bose-Einstein Condensation’, Reviews of Modern Physics, 2010
[3] Rechińska et al., ‘Engineering spin-orbit synthetic Hamiltonians in liquid-crystal optical cavities’, Science, 2019
[4] Panzarini et al., ‘Exciton-light coupling in single and coupled semiconductor microcavities: Polariton dispersion and polarization splitting’, Physical Review B, 1999
[5] Terças et al., ‘Non-Abelian Gauge Fields in Photonic Cavities and Photonic Superfluids’, Physical Review Letters, 2014

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