Narrowband spectroscopy by all-optical correlation of broadband pulses

TL;DR

This paper introduces a novel all-optical correlation method that enhances spectral resolution in ultrafast spectroscopy by detecting narrow spectral correlations between broadband excitation and emission fields, allowing simultaneous detection of multiple resonances.

Contribution

The work presents an alternative approach to high-resolution spectroscopy using all-optical correlation analysis with broadband pulses, improving spectral resolution without complex multi-photon interference techniques.

Findings

Enables direct detection of multiple narrow resonances

Achieves high spectral resolution with single femtosecond pulses

Integrates easily into traditional spectroscopic setups

Abstract

High peak power ultrafast lasers are widely used in nonlinear spectroscopy but often limit its spectral resolution because of the broad frequency bandwidth of ultrashort laser pulses. Improving the resolution by achieving spectrally narrow excitation of, or emission from, the resonant medium by means of multi-photon interferences has been the focus of many recent developments in ultrafast spectroscopy. We demonstrate an alternative approach, in which high resolution is exercised by detecting narrow spectral correlations between broadband excitation and emission optical fields. All-optical correlation analysis, easily incorporated into the traditional spectroscopic setup, enables direct, robust and simultaneous detection of multiple narrow resonances with a single femtosecond pulse.