Collecting single photons from a cavity-coupled quantum dot using an adiabatic tapered fiber

TL;DR

This paper demonstrates a highly efficient method for collecting single photons from quantum dots in photonic crystal cavities using adiabatic tapered fiber coupling, significantly improving collection efficiency over traditional methods.

Contribution

The study introduces an adiabatic tapered fiber coupling technique for quantum dot photon collection, achieving a fivefold efficiency increase and predicting near-unity coupling with optimized parameters.

Findings

Collection efficiency increased five times with tapered fiber

Single photon source characterized by g(2)(0)=0.17

Numerical models suggest further efficiency improvements

Abstract

We demonstrate efficient in-plane optical fiber collection of single photon emission from quantum dots embedded in photonic crystal cavities. This was achieved via adiabatic coupling between a tapered optical fiber and a tapered on-chip photonic waveguide coupled to the photonic crystal cavity. The collection efficiency of a dot in a photonic crystal cavity was measured to be 5 times greater via the tapered optical fiber compared to collection by a microscope objective lens above the cavity. The single photon source was also characterized by second order photon correlations measurements giving g(2)(0)=0.17 under non-resonant excitation. Numerical calculations demonstrate that the collection efficiency could be further increased by improving the dot-cavity coupling and by increasing the overlap length of the tapered fiber with the on-chip waveguide. An adiabatic coupling of near unity is predicted for an overlap length of 5 microns.