Real time $g^{(2)}$ monitoring at 100 kHz

TL;DR

This paper presents a real-time technique for monitoring the second-order photon correlation function $g^{(2)}(0)$ at 100 kHz, enabling dynamic observation of light source emission states.

Contribution

The authors introduce a novel ultrafast homodyne detection method for real-time photon correlation measurements, surpassing previous temporal resolution limits.

Findings

Successfully monitored laser diode emission dynamics in real time.

Achieved $g^{(2)}(0)$ sampling rate of 100 kHz.

Demonstrated switching between lasing and spontaneous emission states.

Abstract

We introduce a technique to determine photon correlations of optical light fields in real time. The method is based on ultrafast phase-randomized homodyne detection and allows us to follow the temporal evolution of the second-order correlation function $g^{(2)}(0)$ of a light field. We demonstrate the capabilities of our approach by applying it to a laser diode operated in the threshold region. In particular, we are able to monitor the emission dynamics of the diode switching back and forth between lasing and spontaneous emission with a $g^{(2)}(0)$-sampling rate of 100 kHz.