Sub-microsecond correlations in photoluminescence from InAs quantum dots

TL;DR

This paper investigates photon correlation effects in InAs quantum dots, revealing memory effects over nanosecond timescales that impact their efficiency and quantum computing applications.

Contribution

It demonstrates the presence of long-timescale correlations in quantum dot emission and introduces a simple model explaining these effects based on charged states.

Findings

Negative correlations (antibunching) with above-band excitation

Positive correlations (blinking) with quasi-resonant excitation

Memory effects can limit quantum dot light emitter efficiency

Abstract

Photon correlation measurements reveal memory effects in the optical emission of single InAs quantum dots with timescales from 10 to 800 ns. With above-band optical excitation, a long-timescale negative correlation (antibunching) is observed, while with quasi-resonant excitation, a positive correlation (blinking) is observed. A simple model based on long-lived charged states is presented that approximately explains the observed behavior, providing insight into the excitation process. Such memory effects can limit the internal efficiency of light emitters based on single quantum dots, and could also be problematic for proposed quantum-computation schemes.