Realization of room temperature polaritonic vortex in momentum space with hybrid Perovskite metasurface

TL;DR

This paper demonstrates the experimental realization of room temperature polaritonic vortices in momentum space using a hybrid perovskite metasurface, revealing topological features and potential for novel optoelectronic devices.

Contribution

It introduces the first observation of polariton BICs at room temperature with topological polarization vortices in a hybrid perovskite metasurface.

Findings

Polaritonic eigenmodes called pol-BICs are observed in reflectivity, scattering, and photoluminescence.

Pol-BICs inherit BIC features, including uncoupling from the radiative continuum.

A polarization vortex in farfield emission confirms the topological nature of pol-BICs.

Abstract

Exciton-polaritons are mixed light-matter excitations that result from the strong coupling regime between an active excitonic material and photonic resonances. Harnessing these hybrid excitations provides a rich playground to explore fascinating fundamental features, such as out-of-equilibrium Bose-Einstein condensation and quantum fluids of light, as well as novel mechanisms to be exploited in optoelectronic devices. Here, we investigate experimentally the formation of exciton-polaritons arising from the mixing between hybrid inorganic-organic perovskite excitons and an optical Bound state In a Continuum (BIC) of a subwavelength-scale metasurface, at room temperature. These polaritonic eigenmodes, hereby called polariton BICs (pol-BICs) are revealed in both reflectivity, resonant scattering, and photoluminescence measurements. Although pol-BICs only exhibit a finite quality factor that is bounded by the non-radiative losses of the excitonic component, they fully inherit BIC peculiar features: a full uncoupling from the radiative continuum in the vertical direction, which is associated to a locally vanishing farfield radiation in momentum space. Most importantly, our experimental results confirm that the topological nature of the photonic BIC is perfectly transferred to the pol-BIC. This is evidenced with the observation of a polarization vortex in the farfield of polaritonic emission. Our results pave the way to engineer BIC physics of interacting bosons, as well as novel room temperature polaritonic devices.