Active feedback of a Fabry-Perot cavity to the emission of a single InAs/GaAs quantum dot

TL;DR

This paper demonstrates active feedback control of a Fabry-Perot cavity to stabilize and enhance the emission measurement of a single InAs/GaAs quantum dot, achieving high spectral resolution and stability.

Contribution

It introduces a method for actively locking a Fabry-Perot cavity to a single quantum dot emission, improving measurement stability and spectral resolution.

Findings

Achieved photoluminescence linewidths as low as 0.9 GHz.

Locked the cavity to the quantum dot emission with stability below 2%.

Optimal integration time of about two seconds balances noise and stability.

Abstract

We present a detailed study of the use of Fabry-Perot (FP) cavities for the spectroscopy of single InAs quantum dots (QDs). We derive optimal cavity characteristics and resolution limits, and measure photoluminescence linewidths as low as 0.9 GHz. By embedding the QDs in a planar cavity, we obtain a sufficiently large signal to actively feed back on the length of the FP to lock to the emission of a single QD with a stability below 2% of the QD linewidth. An integration time of approximately two seconds is found to yield an optimum compromise between shot noise and cavity length fluctuations.