Absolute measurement of the ultrafast nonlinear electronic and rovibrational response in H$_2$ and D$_2$

TL;DR

This paper provides the first absolute measurements of the ultrafast electronic, rotational, and vibrational nonlinear responses in H₂ and D₂ molecules at high intensities, serving as a benchmark for theoretical models.

Contribution

It presents direct, absolute measurements of the nonlinear optical responses in H₂ and D₂, which are fundamental molecules, at intensities near the ionization threshold, filling a key gap in experimental data.

Findings

Measured electronic, rotational, and vibrational nonlinear responses.

Established benchmarks for high field laser-matter interaction theories.

Provided data up to the ionization threshold of ~10^14 W/cm^2.

Abstract

The electronic, rotational, and vibrational components of the ultrafast optical nonlinearity in H$_2$ and D$_2$ are measured directly and absolutely at intensities up to the ionization threshold of $\sim$10$^{14}$ W/cm$^2$. As the most basic nonlinear interactions of the simplest molecules exposed to high fields, these results constitute a benchmark for high field laser-matter theory and simulation.