Nonclassical light from an incoherently pumped quantum dot in a microcavity

TL;DR

This paper investigates the quantum state of light emitted from an incoherently pumped quantum dot in a microcavity, demonstrating that the intracavity field is inherently nonclassical under realistic conditions.

Contribution

It introduces a new, efficient method to analyze the steady-state correlations in incoherently driven cavity QED systems, providing analytical insights into their quantum states.

Findings

The intracavity field is nonclassical for all realistic parameters.

The method simplifies the analysis of steady-state correlations.

Analytical bounds on quantum state properties are derived.

Abstract

Semiconductor microcavities with artificial single-photon emitters have become one of the backbones of semiconductor quantum optics. In many cases however, technical and physical issues limit the study of optical fields to incoherently excited systems. We analyze the model of a two-level system in a single-mode cavity, where the former is incoherently driven. The specific structure of the applied master equation yields a recurrence relation for the steady-state values of correlations of the intracavity field and the emitter. We provide boundary conditions, that permit a systematical, easy to implement solution, which is numerically less demanding than standard methods. Different cavity systems from previous experiments are analyzed. The derived boundary conditions also allow us direct analytical statements about the overall quantum state and its higher order moments. With this we can give very good approximations for the full quantum state of the field and show, that for every physically reasonable set of system parameters, the state of the intracavity field is nonclassical.