Post-processing of real-time quantum event measurements for an optimal bandwidth

TL;DR

This paper demonstrates a post-processing method for real-time quantum event measurements using optical detection in quantum dots, achieving high bandwidth analysis up to 350 kHz and discussing potential improvements beyond 1 MHz.

Contribution

It introduces a novel post-processing approach for quantum event detection via optical signals, enabling high bandwidth analysis without requiring advanced lithography or low temperatures.

Findings

Achieved bandwidths up to 350 kHz in data analysis.

Post-processing improves the determination of tunneling rates.

Discussed potential for exceeding 1 MHz bandwidth with current models.

Abstract

Single electron tunneling and its transport statistics have been studied for some time using high precision charge detectors. However, this type of detection requires advanced lithography, optimized material systems and low temperatures (mK). A promising alternative, recently demonstrated, is to exploit an optical transition that is turned on or off when a tunnel event occurs. High bandwidths should be achievable with this approach, although this has not been adequately investigated so far. We have studied low temperature resonance fluorescence from a self-assembled quantum dot embedded in a diode structure. We detect single photons from the dot in real time and evaluate the recorded data only after the experiment, using post-processing to obtain the random telegraph signal of the electron transport. This is a significant difference from commonly used charge detectors and allows us to determine the optimal time resolution for analyzing our data. We show how this post-processing affects both the determination of tunneling rates using waiting-time distributions and statistical analysis using full-counting statistics. We also demonstrate, as an example, that we can analyze our data with bandwidths as high as 350 kHz. Using a simple model, we discuss the limiting factors for achieving the optimal bandwidth and propose how a time resolution of more than 1 MHz could be achieved.