Nonlinear photon transport in a semiconductor waveguide-cavity system containing a single quantum dot: Anharmonic cavity-QED regime

TL;DR

This paper develops a semiconductor master equation approach to analyze nonlinear photon transport in a waveguide-cavity system with a quantum dot, revealing breakdown of weak excitation approximation and phonon effects.

Contribution

It introduces a novel master equation technique for semiconductor systems and explores anharmonic cavity-QED effects across different coupling regimes.

Findings

Weak excitation approximation fails at photon numbers < 0.1.

Phonon scattering significantly affects photon transport.

Simulated a conditional phase gate in the strong coupling regime.

Abstract

We present a semiconductor master equation technique to study the input/output characteristics of coherent photon transport in a semiconductor waveguide-cavity system containing a single quantum dot. We use this approach to investigate the effects of photon propagation and anharmonic cavity-QED for various dot-cavity interaction strengths, including weakly-coupled, intermediately-coupled, and strongly-coupled regimes. We demonstrate that for mean photon numbers much less than 0.1, the commonly adopted weak excitation (single quantum) approximation breaks down, even in the weak coupling regime. As a measure of the anharmonic multiphoton-correlations, we compute the Fano factor and the correlation error associated with making a semiclassical approximation. We also explore the role of electron--acoustic-phonon scattering and find that phonon-mediated scattering plays a qualitatively important role on the light propagation characteristics. As an application of the theory, we simulate a conditional phase gate at a phonon bath temperature of $20 $K in the strong coupling regime.