Cavity-enhanced field-free molecular alignment at a high repetition rate

TL;DR

This paper demonstrates cavity-enhanced, high-repetition-rate field-free molecular alignment and high-order harmonic generation using extreme ultraviolet frequency combs, advancing precision in strong-field molecular physics studies.

Contribution

It introduces a novel cavity-enhanced system enabling high-repetition-rate molecular alignment and harmonic generation, improving experimental capabilities in strong-field physics.

Findings

Successful molecular alignment at 154 MHz repetition rate

Observation of field modulations from impulsive stimulated Raman scattering

Enhanced effects of molecule-field interactions

Abstract

Extreme ultraviolet frequency combs are a versatile tool with applications including precision measurement, strong-field physics, and solid-state physics. Here we report on an application of extreme ultraviolet frequency combs and their driving lasers for studying strong-field effects in molecular systems. We perform field-free molecular alignment and high-order harmonic generation with aligned molecules in a gas jet at a repetition rate of 154 MHz using a high-powered optical frequency comb inside a femtosecond enhancement cavity. The cavity-enhanced system provides a means to reach suitable intensities to study field-free molecular alignment and enhance the observable effects of the molecule-field interaction. We observe modulations of the driving field, arising from the nature of impulsive stimulated Raman scattering responsible for coherent molecular rotations. We foresee the impact of this work on the study of molecule-based strong-field physics, with improved precision and a more fundamental understanding of the interaction effects on both the field and molecules.