Spin polarization of exciton-polariton condensate in a photonic synthetic effective magnetic field

TL;DR

This study explores how a photonic synthetic magnetic field influences the spin polarization of exciton-polariton condensates in CdTe microcavities, revealing a photonic origin of the effective magnetic field and quantifying interaction strengths.

Contribution

It demonstrates the existence of a purely photonic synthetic magnetic field affecting polariton spin polarization and provides a model to estimate polariton-polariton interaction strength in CdTe systems.

Findings

Elliptically polarized condensates due to synthetic magnetic field

Spin polarization depends on excitation power and polarization

Strong spin polarization in external magnetic field

Abstract

We investigate the spin polarization of localized exciton-polariton condensates. We demonstrate the presence of an effective magnetic field leading to the formation of elliptically polarized condensates. We show that this synthetic field has an entirely photonic origin, which we believe is unique for the CdTe-based microcavities. Moreover, the degree of spin polarization of localized polariton condensates in samples with magnetic ions depends on the excitation power or polarization of the non-resonant excitation laser. In an external magnetic field, the semimagnetic condensate spontaneously builds up strong spin polarization. Based on the magnetic field behavior of the condensate in the presence of magnetic ions, we apply a model that allows us to estimate the polariton-polariton interaction strength in a CdTe-system to approx. 0.8 $\mu \text{eV}\!\cdot\!\mu \text{m}^2$.