Probing the excitation spectrum of nonresonantly pumped polariton condensates

TL;DR

This paper introduces a four wave mixing technique to experimentally probe the excitation spectrum of non-equilibrium polariton condensates, revealing key features of their Bogoliubov dispersion through analytical and numerical analysis.

Contribution

It presents a novel experimental approach using four wave mixing to directly measure the excitation spectrum of non-resonantly pumped polariton condensates, supported by theoretical and simulation validation.

Findings

The method can detect the negative energy feature of the Bogoliubov dispersion.

Analytical mean-field calculations support the technique's effectiveness.

Numerical simulations confirm the method's applicability to realistic experimental conditions.

Abstract

We propose a four wave mixing experiment to probe the elementary excitation spectrum of a non-equilibrium Bose-Einstein condensate of exciton-polaritons under non-resonant pumping. Analytical calculations based on mean-field theory show that this method is able to reveal the characteristic negative energy feature of the Bogoliubov dispersion. Numerical simulations including the finite spatial profile of the excitation laser spot and a weak disorder confirm the practical utility of the method for realistic condensates.