Enhanced light collection from a gallium nitride color center using a near index-matched solid immersion lens

TL;DR

This paper demonstrates that using a near index-matched solid immersion lens significantly enhances photon collection efficiency and lateral resolution from a gallium nitride color center emitting at room temperature.

Contribution

It introduces a novel application of a hemispherical solid immersion lens to improve light collection from GaN color centers at room temperature.

Findings

Photon collection efficiency increased by a factor of 4.3

Lateral resolution improved proportionally to the refractive index

Effective enhancement of quantum light extraction from GaN centers

Abstract

Among the wide-bandgap compound semiconductors, gallium nitride is the most widely available material due to its prevalence in the solid state lighting and high-speed/high-power electronics industries. It is now known that GaN is one of only a handful of materials to host color centers that emit quantum light at room temperature. In this paper, we report on a bright color center in a semi-polar gallium nitride substrate, emitting at room temperature in the near-infrared. We show that a hemispherical solid immersion lens, near index matched to the semiconductor, can be used to enhance the photon collection efficiency by a factor of $4.3\pm0.1$, whilst improving the lateral resolution by a factor equal to the refractive index of the lens.