Efficient light extraction from an apex quantum dot coupled to a single-mode optical fiber

Abstract

Deterministic quantum dots (apex-QDs), which are spontaneously formed at the vertex of pyramid structures, are an attractive single-photon source. Herein, we propose the design of apex-QDs coupled to a single-mode optical fiber for directional emission from a quantum dot, followed by optimization of the structural parameters to maximize the extraction efficiency toward the fiber using FDTD simulation. A dielectric layer of SiO2 was inserted between a silver and a quantum dot to minimize the metallic loss and control the distance between them. For this, the optimum layer thicknesses of silver and SiO2 were 100 rim and 240 nm, respectively, achieving 94% light collection downward near 600 nm in wavelength. The proposed structure was then coupled to a tapered optical fiber, achieving 60% of the quantum dot emission. This high collection through an optical fiber was observed for a wide range of emission wavelengths. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement