Directional single-photon emission from deterministic quantum dot waveguide structures

TL;DR

This paper demonstrates deterministic integration of quantum dots into waveguides to achieve highly directional, circularly polarized single-photon emission, advancing on-chip quantum photonic technologies.

Contribution

It introduces a low-temperature electron-beam lithography method for precise quantum dot placement in waveguides, enabling high-directionality and polarization control of emitted photons.

Findings

54% directional emission anisotropy

Antibunching confirms single-photon emission

Deterministic quantum dot-waveguide integration achieved

Abstract

Chiral light-matter interaction can lead to directional emission of two-level light emitters in waveguides. This interesting physics effect has raised considerable attention in recent years especially in terms of on-chip quantum systems. In this context, our work focuses on tailoring single semiconductor quantum dot-waveguide (QD-WG) systems to emit single photons with high directionality. We use low-temperature in-situ electron-beam lithography enabled by cathodoluminescence mapping to select suitable QDs and to integrate them deterministically into linear waveguide structures at specific chiral points determined by numerical calculations. We observe excitonic and biexcitonic emission from the fabricated QD-WG structure in a confocal microPL setup enabling the optical characterization in terms of directional emission of circularly polarized photons emitted by integrated QDs. Our results show a high degree of anisotropy on the level of 54% for directional QD emission and antibunching in autocorrelation experiment confirming the fabricated QD-WG system, which is a prerequisite for using this effect in advanced applications in integrated quantum circuits.