Second-order correlation function supported optical sensing for particle detection

TL;DR

This paper introduces a novel optical sensing method using second-order autocorrelation of laser output with feedback, enabling sensitive detection suitable for biomolecular and security applications.

Contribution

The paper presents a new feedback-based sensing technique leveraging photon statistics of micro- and nanolasers, adaptable for various sensor types.

Findings

Effective feedback-induced threshold shift for sensing

Two schemes for quantitative feedback measurement

Potential applications in biomolecular diagnostics and security

Abstract

We propose a new sensing method based on the measurement of the second-order autocorrelation of the output of micro- and nanolasers with intensity feedback. The sensing function is implemented through the feedback-induced threshold shift, whose photon statistics is controlled by the feedback level in a characteristic way for different laser sizes. The specific response offers performances which can be adapted to different kinds of sensors. We propose the implementation of two schemes capable of providing a quantitative sensing signal and covering a broad range of feedback levels: one is utilizing the evolution of g$^{(2)}$(0), the other one is the ratio between central and side peaks in g$^{(2)}(\tau)$. Laser-threshold-based sensing could, thanks to its potential sensitivity, gain relevance in biomolecular diagnostics and security monitoring.