Anisotropic exciton polariton pairs as a platform for PT-symmetric non-Hermitian physics

Non-Hermitian PT-symmetric systems can be conveniently realized in optical systems in the classical domain and have been used to explore a plethora of exotic phenomena like loss-induced lasing and selective propagation of chiral modes in waveguides. On the other hand, a microcavity exciton-polariton system is intrinsically non-Hermitian in the quantum regime. However, realization of such systems in the PT-symmetric phase has not been achieved so far. Here we show how a pair of nearly orthogonal sets of anisotropic exciton-polaritons can offer a versatile platform for realizing multiple Eps and propose a roadmap to achieve a PT-symmetric system. By utilizing the tunability of coupling strength and energy detuning on the polarization of probe beam, the angle of incidence, and the orientation of the anisotropic sample, we realise two kinds of Eps: Polarization-tunable polariton dispersion creates one set of EPs based on tunable coupling strength, while the rotating the sample reveals Voigt EPs for specific orientations. Pair of anisotropic microcavity exciton-polaritons can offer a promising platform not only for fundamental research in non-Hermitian quantum physics and topological polaritons but also, we have proposed that it can offer a system to realize zero threshold laser.