First- and second-order coherence properties of a quantum-dot micropillar laser

TL;DR

This paper investigates the coherence properties of a quantum-dot micropillar laser, revealing high polarization purity and record coherence times, and introduces a theoretical model to fully characterize its emission.

Contribution

It provides the first detailed analysis of both first- and second-order coherence in a quantum-dot micropillar laser, including a new theoretical framework for emission characterization.

Findings

Polarization-insensitive measurements show a degree of linear polarization of 0.99 in the coherent regime.

The stronger mode exhibits a record coherence time of 20 ns.

A theoretical model accurately characterizes cavity emission using $g^{(1)}( au)$ and $g^{(2)}( au)$) data.

Abstract

We present investigations on the coherence of the emission from the polarization split fundamental mode of an AlGaInAs/GaAs quantum-dot microcavity laser. Using polarization insensitive measurements of the first-order field-correlation function $g^{(1)}(\tau)$ we determine the power-dependent degree of polarization. Whereas the orthogonally-polarized components of the fundamental mode exhibit comparable strength below the lasing threshold, a degree of linear polarization of 0.99 is observed in the coherent regime. This is also observed for increasing temperatures up to 77K. Furthermore, by measuring $g^{(1)}(\tau)$ for both modes separately the stronger mode is found to reveal a record coherence time of 20ns. Finally, based on a theoretical model it is possible to fully characterize the cavity emission in terms of first- and second-order coherence using auxiliary data from $g^{(2)}(\tau)$ measurements performed with a recently developed streak camera technique.