Fast phase cycling in non-collinear optical two-dimensional coherent spectroscopy

TL;DR

This paper introduces a rapid phase-cycling method using liquid crystal retarders in non-collinear optical 2DCS, significantly improving detection sensitivity for broader application potential.

Contribution

It presents a novel fast phase-cycling scheme with liquid crystal retarders for non-collinear optical 2DCS, enhancing signal detection and background elimination.

Findings

Validated in atomic vapor measurements

Effective background suppression with fewer interferograms

Potential to enable new applications requiring high sensitivity

Abstract

As optical two-dimensional coherent spectroscopy (2DCS) is extended to a broader range of applications, it is critical to improve the detection sensitivity of optical 2DCS. We developed a fast phase-cycling scheme in a non-collinear optical 2DCS implementation by using liquid crystal phase retarders to modulate the phases of two excitation pulses. The background in the signal can be eliminated by combining either two or four interferograms measured with a proper phase configuration. The effectiveness of this method was validated in optical 2DCS measurements of an atomic vapor. This fast phase-cycling scheme will enable optical 2DCS in novel emerging applications that require enhanced detection sensitivity.