Phase-Modulated Rapid-Scanning Fluorescence-Detected Two-Dimensional Electronic Spectroscopy

TL;DR

This paper introduces a rapid-scanning fluorescence-detected 2D electronic spectroscopy method combining phase modulation and lock-in detection, enabling fast, accurate measurements with noise suppression and spectral phase correction.

Contribution

The paper presents a novel rapid-scanning approach that integrates acousto-optic phase modulation with digital lock-in detection for fluorescence-detected 2D spectroscopy.

Findings

Successfully measured linear fluorescence excitation spectrum

Captured rephasing, non-rephasing, and absorptive 2D spectra

Achieved noise suppression and spectral phase correction

Abstract

We present a rapid-scanning approach to fluorescence-detected two-dimensional electronic spectroscopy that combines acousto-optic phase-modulation with digital lock-in detection. The approach shifts the signal detection window to suppress 1/f laser noise and enables interferometric tracking of the time delays to allow for correction of spectral phase distortions and accurate phasing of the data. This use of digital lock-in detection enables acquisition of linear and nonlinear signals of interest in a single measurement. We demonstrate the method on a laser dye, measuring the linear fluorescence excitation spectrum, as well as rephasing, non-rephasing and absorptive fluorescence-detected two-dimensional electronic spectra.