Optically driven spin precession in polariton condensates

TL;DR

This paper demonstrates an all-optical method to induce and control spin precession in polariton condensates, achieving GHz frequencies and long coherence times by using a rotating exciton reservoir to prevent depolarization.

Contribution

It introduces a novel all-optical technique for spin precession in polariton condensates that overcomes inter-particle interaction limitations on spin coherence.

Findings

Achieved GHz spin precession frequencies.

Extended spin coherence time limited only by external frequency drift.

Supported by mean field modelling showing NMR-like behavior.

Abstract

External driving of spinor degrees of freedom by magnetic or optical fields in quantum systems underpin many applications ranging from nuclear magnetic resonance to coherent state control in quantum computing. Although spinor polariton condensates are offering a flexible platform for spinoptronic applications, strong inter-particle interactions limit their spin coherence. Here, we introduce an all-optically driven spin precession in microcavity polariton condensates that eliminates depolarisation, through a radio frequency modulation of a spatially rotating, asymmetric exciton reservoir that both confines, and actively replenishes the polariton condensate. We realise several GHz driven spin precession with a macroscopic spin coherence time that is limited only by the extraneous to the condensate, frequency drift of the composite pumping sources. Our observations are supported by mean field modelling and evidence a driven-dissipative quantum fluidic analogue of the nuclear magnetic resonance effect.