Optical Anisotropy and Pinning of the Linear Polarization of Light in Semiconductor Microcavities

TL;DR

This study demonstrates strong optical anisotropy in CdTe microcavities, where light polarization is fixed to crystallographic axes and can reach near-perfect polarization under high excitation, due to polariton splitting caused by birefringence.

Contribution

It provides experimental evidence of polarization pinning and high polarization degrees in semiconductor microcavities, attributing these effects to cavity birefringence and polariton splitting.

Findings

Polarization is pinned to crystallographic axes.

Polarization degree reaches nearly 100% at high excitation.

Polarization relaxation time is about 1 ns.

Abstract

We report a strong experimental evidence of the optical anisotropy in a CdTe-based microcavity: the polarization of light is pinned to one of the crystallographic axes independently on the polarization of the excitation. The polarization degree depends strongly on the excitation power, reaching almost 100 % in the stimulated regime. The relaxation time of the polarization is about 1 ns. We argue that all this is an effect of a splitting of the polariton doublet at k=0. We consider different sources for the splitting and conclude that the most likely one is optical birefringence in the mirrors and/or the cavity.