Cavity-enhanced real-time monitoring of single charge jumps at the microsecond timescale

TL;DR

This paper demonstrates a cavity-enhanced optical method for real-time detection of single charge jumps at microsecond timescales, significantly surpassing previous speeds and enabling monitoring of rapid quantum events.

Contribution

It introduces a high-speed, cavity-enhanced reflectivity measurement technique for real-time single-charge monitoring with unprecedented temporal resolution.

Findings

Measurement rate is five orders of magnitude faster than previous methods.

Transitions are identified with less than 0.2% error probability.

Technique enables monitoring of rapid quantum events like single spin jumps.

Abstract

We use fast coherent reflectivity measurements, in a strongly-coupled quantum dot-micropillar device, to monitor in real-time single-charge jumps at the microsecond timescale. Thanks to the strong enhancement of light-matter interaction inside the cavity, the measurement rate is five orders of magnitude faster than with previous experiments of direct single-charge sensing with quantum dots. The monitored transitions, identified at any given time with a less than 0.2% error probability, correspond to a carrier being captured and then released by a single material defect. This high-speed technique opens the way for the real-time monitoring of other rapid single quantum events, such as the quantum jumps of a single spin.