Photon Statistics for Single Molecule Non-Linear Spectroscopy

TL;DR

This paper develops a theoretical framework for photon counting in single-molecule non-linear spectroscopy, providing exact solutions and analyzing how external field design reveals unique molecular dynamics insights.

Contribution

It introduces a comprehensive theory for photon statistics in single-molecule non-linear spectroscopy, including exact solutions for the Kubo-Anderson process and analysis of different experimental limits.

Findings

Exact photon counting statistics for stochastic molecular dynamics

Photon statistics depend on the molecule's dipole correlation function

External field design influences the insights into molecular behavior

Abstract

We consider the theory of the non-linear spectroscopy for a single molecule undergoing stochastic dynamics and interacting with a sequence of two laser pulses. General expressions for photon counting statistics are obtained, and an exact solution to the problem of the Kubo-Anderson process is found. In the limit of impulsive pulses the information on the photon statistics is contained in the molecule's dipole correlation function. The selective limit where temporal resolution is maintained, the semi-classical approximation and the fast modulation limit exhibit general behaviors of this new type of spectroscopy. We show how the design of the external field leads to rich insights on dynamics of individual molecules which are different than those found for an ensemble.