Extraction of the beta-factor for single quantum dots coupled to a photonic crystal waveguide

TL;DR

This paper measures the coupling efficiency (beta-factor) of single quantum dots to photonic crystal waveguides, demonstrating high emission rates and potential for on-chip single-photon sources.

Contribution

It introduces a method to evaluate the beta-factor of quantum dots in photonic crystal waveguides using time-resolved photoluminescence spectroscopy.

Findings

Beta-factors up to 85% were achieved.

Spontaneous emission rates up to 5.7 ns^(-1) were measured.

The results highlight the potential for integrated quantum photonics.

Abstract

We present measurements of the beta-factor, describing the coupling efficiency of light emitted by single InAs/GaAs semiconductor quantum dots into a photonic crystal waveguide mode. The beta-factor is evaluated by means of time-resolved frequency-dependent photoluminescence spectroscopy. The emission wavelength of single quantum dots is temperature tuned across the band edge of a photonic crystal waveguide and the spontaneous emission rate is recorded. Decay rates up to 5.7 ns^(-1), corresponding to a Purcell factor of 5.2, are measured and beta-factors up to 85% are extracted. These results prove the potential of photonic crystal waveguides in the realization of on-chip single-photon sources.