Large-Range Frequency Tuning of a Narrow-Linewidth Quantum Emitter

TL;DR

This paper demonstrates a method to reversibly tune the emission frequency of a narrow-linewidth quantum dot over a large range using piezoelectric strain, maintaining its quantum properties, which is crucial for quantum networking applications.

Contribution

The authors introduce a piezoelectric strain technique for large-range, reversible frequency tuning of high-quality quantum dots while preserving their emission properties.

Findings

Frequency shift of 1.15 THz achieved

Quantum dot properties preserved during tuning

Reversible tuning enabled by strain application

Abstract

A hybrid system of a semiconductor quantum dot single photon source and a rubidium quantum memory represents a promising architecture for future photonic quantum repeaters. One of the key challenges lies in matching the emission frequency of quantum dots with the transition frequency of rubidium atoms while preserving the relevant emission properties. Here, we demonstrate the bidirectional frequency-tuning of the emission from a narrow-linewidth (close-to-transform-limited) quantum dot. The frequency tuning is based on a piezoelectric strain-amplification device, which can apply significant stress to thick bulk samples. The induced strain shifts the emission frequency of the quantum dot over a total range of $1.15\ \text{THz}$, about three orders of magnitude larger than its linewidth. Throughout the whole tuning process, both the spectral properties of the quantum dot and its single-photon emission characteristics are preserved. Our results show that external stress can be used as a promising tool for reversible frequency tuning of high-quality quantum dots and pave the wave towards the realisation of a quantum dot -- rubidium atoms interface for quantum networking.