Resonance fluorescence revival in a voltage-controlled semiconductor quantum dot

TL;DR

This study demonstrates near-perfect resonance fluorescence in voltage-controlled quantum dots, enabling stable, efficient single-photon emission by suppressing charge noise through electric field tuning.

Contribution

It introduces a charge-tunable device that stabilizes quantum dot charge states, significantly enhancing resonance fluorescence efficiency and coherence.

Findings

Resonance fluorescence efficiency approaches unity.

Electric field stabilizes charge states, reducing noise.

Quantum dots act as deterministic single-photon sources.

Abstract

We demonstrate systematic resonance fluorescence recovery with near-unity emission efficiency in single quantum dots embedded in a charge-tunable device in a wave-guiding geometry. The quantum dot charge state is controlled by a gate voltage, through carrier tunneling from a close-lying Fermi sea, stabilizing the resonantly photocreated electron-hole pair. The electric field cancels out the charging/discharging mechanisms from nearby traps toward the quantum dots, responsible for the usually observed inhibition of the resonant fluorescence. Fourier transform spectroscopy as a function of the applied voltage shows a strong increase of the coherence time though not reaching the radiative limit. These charge controlled quantum dots act as quasi-perfect deterministic single-photon emitters, with one laser pulse converted into one emitted single photon.