# Attosecond probing of nuclear dynamics with trajectory-resolved high-harmonic spectroscopy

## TL;DR

This paper demonstrates attosecond-scale probing of molecular nuclear dynamics using high-harmonic spectroscopy, distinguishing electron trajectories to extend temporal measurement range and capture detailed nuclear motion.

## Contribution

It introduces a method to differentiate short and long electron trajectories in high-harmonic generation, enabling extended temporal resolution of molecular dynamics.

## Key findings

- Successfully retrieved nuclear dynamics in H2 and D2 molecules.
- Extended measurement range to one optical cycle using trajectory separation.
- Applied technique to methane and ammonia molecules.

## Abstract

We report attosecond-scale probing of the laser-induced dynamics in molecules. We apply the method of high-harmonic spectroscopy, where laser-driven recolliding electrons on various trajec- tories record the motion of their parent ion. Based on the transient phase-matching mechanism of high-order harmonic generation, short and long trajectories contributing to the same harmonic order are distinguishable in both the spatial and frequency domains, giving rise to a one-to-one map between time and photon energy for each trajectory. The short and long trajectories in H2 and D2 are used simultaneously to retrieve the nuclear dynamics on the attosecond and angstrom scale. Compared to using only short trajectories, this extends the temporal range of the measurement to one optical cycle. The experiment is also applied to methane and ammonia molecules.