Extracting the sample response function from experimental two-dimensional terahertz-infrared-visible spectra

TL;DR

This paper introduces a method to extract the intrinsic sample response from two-dimensional terahertz-infrared-visible spectra, enabling more accurate analysis of molecular vibrations unaffected by laser pulse variations.

Contribution

The work presents a novel technique for isolating the physical response of a sample from complex spectroscopic data, verified on DMSO molecules.

Findings

Successfully extracted the sample response from experimental spectra.

Demonstrated coupling between C-H stretch and terahertz modes in DMSO.

Method improves the accuracy of vibrational spectroscopy analysis.

Abstract

Terahertz molecular motions are often probed by high-frequency molecular oscillators in different types of non-linear vibrational spectroscopy. Recently developed two-dimensional terahertz-infrared-visible spectroscopy allows direct measuring of this coupling and, thus, obtaining site-specific terahertz vibrational spectrum. However, these data are affected by the intensity and phase of the employed laser pulses. In this work, we develop a method of extracting sample response - representing solely physical properties of a material - from experimental spectra. Using dimethyl sulfoxide (DMSO) as a model molecule to verify this method, we measure the coupling between C-H stretch vibration of its methyl groups and terahertz intramolecular twist and wagging modes.