Mateusz Król, Warsaw University of Technology
Incorporation of the liquid crystals inside an optical cavity allows for tunability of the resonance energy through control over the LC optical anisotropy direction by an external electric field. Additionally, when the cavity modes are brought close to the resonance, they can couple, achieving an effective Rashba-Dresselhaus spin orbit coupling Hamiltonian. As a result, the dispersion relation of the cavity photonic modes consists of two circularly polarized valleys separated in the wave vector.
In this work we realize a hybrid liquid crystal microcavity in which photonic modes in Rashba-Dresselhauss SOC regime are additionally strongly coupled to an excitonic resonance in a perovskite layer. We use 2D organic-inorganic perovskites which are characterized with strong optical nonlinearities and their high exciton binding energy allows for achieving strong coupling regime at room temperature. We observe anticrossing behavior in the dispersion relation, which is characteristic for mixed light-matter quasiparticles referred to as exciton polaritons.
By preparation of the orienting layers within the cavity to break inversion symmetry of the liquid crystal layer we were able to engineer a polariton energy band structure exhibiting locally nonzero Berry curvature. Thanks to the tunablility of the liquid crystal we are able to alter the energy structure to achieve electric control over the observed photonic Berry curvature.
About the presenter
Dr Mateusz Król is a research associate at Warsaw University of Technology.