Polarization-inverting polariton parametric scattering in birefringent CsPbBr₃ microcavities

Exciton-polaritons, a hybrid of light and matter, have been intensively investigated for their applications to optical parametric oscillations due to the substantial nonlinearity inherent to the polaritons, which surpasses that of conventional spontaneous parametric down conversion processes by orders of magnitude [1, 2]. Notably, the S-shaped dispersion of polaritons offers a unique advantage in achieving phase-matched parametric oscillations. However, the practical utilization of intra-branch parametric oscillation encounters certain challenges, as it necessitates a resonant excitation precisely at the inflection point of the polariton dispersions. In this study, we demonstrate the polarization-inverting parametric scattering among polariton inter-subbranch in CsPbBr₃ microcavities under non-resonant excitation conditions. The inherent optical anisotropy of CsPbBr₃, characterized by an orthorhombic phase, results in the polarization splitting of polariton branches at zero in-plane momentum, enabling polariton condensates at polarization splitting polariton modes. Through energy-degenerate polariton parametric scattering, we achieve the parametric scattering with a phase matching in-between the polariton branches. The findings of our study can facilitate the practical realization of non-linear polaritonic devices.

[1] H. Deng, H. Haug, and Y. Yamamoto, “Exciton–polariton Bose–Einstein condensation,” Rev. Mod. Phys. 82(2), 1489–1537 (2010).

[2] T. Byrnes, N. Y. Kim, and Y. Yamamoto, “Exciton–polariton condensates,” Nat. Phys. 10(11), 803–813 (2014).