Orientation Echoes via Concerted Terahertz and Near-IR excitation

TL;DR

This paper introduces a novel all-optical orientation echo spectroscopy technique using combined terahertz and near-IR pulses, enabling detailed study of molecular rotational dynamics in gases.

Contribution

It presents an efficient experimental method for orientation echo spectroscopy that leverages concerted ultrashort terahertz and near-IR pulses with all-optical detection.

Findings

Demonstrated practical orientation echo spectroscopy in gas-phase molecules.

Revealed underlying physics of coherent rotational dynamics.

Enabled all-optical detection via Molecular Orientation Induced Second Harmonic.

Abstract

A new and efficient method for orientation echo spectroscopy is presented and realized experimentally. The excitation scheme utilizes concerted rotational excitations by both ultrashort terahertz and near-IR pulses and its all-optical detection is enabled by Molecular Orientation Induced Second Harmonic method [J.Phys.Chem.A 126, 3732-3738 (2022)]. The method provides practical means for orientation echo spectroscopy of gas phase molecules and highlights the intriguing underlying physics of coherent rotational dynamics induced by judiciously-orchestrated interactions with both resonant (terahertz) and nonresonant (NIR) light pulses.