Alignment dependence of photoelectron momentum distributions for diatomic molecules N$_2$ in strong elliptical laser fields

TL;DR

This study investigates how the alignment of N$_2$ molecules affects photoelectron momentum distributions in strong elliptical laser fields, revealing significant dependence and implications for ultrafast electron dynamics.

Contribution

It provides experimental and theoretical analysis of alignment-dependent PMDs in N$_2$, highlighting the roles of two-center interference and tunneling in strong-field ionization.

Findings

PMDs depend strongly on molecular alignment.

The most-probable emission angle varies with alignment.

Interplay of interference and tunneling influences ionization dynamics.

Abstract

We study ionization dynamics of aligned diatomic molecules N$_2$ in strong elliptical laser fields experimentally and theoretically. The alignment dependence of photoelectron momentum distributions (PMDs) of N$_2$ measured in experiments is highlighted with comparing to Ar measured synchronously. Our results show that the PMDs of N$_2$ depend strongly on the alignment of the molecule, relative to the main axis of the laser ellipse. In particular, the most-probable electron-emission angle which is often used in attosecond measurement, differs remarkably when changing the molecular alignment. We show that the interplay of two-center interference and tunneling when the electron goes through the laser-Coulomb-formed barrier, plays an important role in these phenomena. Our work gives suggestions on studying ultrafast electron motion inside aligned molecules.