Diffusive Propagation of Exciton-Polaritons through Thin Crystal Slabs

TL;DR

This paper investigates how exciton-polaritons propagate diffusively through thin GaAs crystal slabs, revealing a surprising absorption scaling with impurity concentration that supports a diffusive propagation model.

Contribution

It demonstrates experimentally and analytically that exciton-polariton propagation in GaAs slabs follows a diffusive mechanism, evidenced by the N^{1/6} absorption scaling across various impurity levels.

Findings

Normalized absorption scales as N^{1/6}

Diffusive propagation explains the observed scaling

Impurity concentration varies over five orders of magnitude

Abstract

Comparative studies of the resonant transmission of light in the vicinity of exciton resonances, measured for 15 few-micron GaAs crystal slabs with different impurity concentrations $N$, reveal an unexpected tendency. While $N$ spans almost five decimal orders of magnitude, the normalized spectrally-integrated absorption of light scales with the impurity concentration as $N^{1/6}$. We show analytically that this dependence is a signature of the diffusive mechanism of propagation of exciton-polaritons in the semiconductor.