Roles of laser ellipticity in attoclock

TL;DR

This paper investigates how laser ellipticity influences the offset angle in photoelectron momentum distributions during strong-field ionization, providing numerical and analytical insights relevant for attoclock experiments.

Contribution

It introduces new scaling laws for ellipticity dependence of the offset angle and Coulomb-induced ionization time lag, advancing understanding of attoclock measurements.

Findings

Offset angle increases as ellipticity decreases.

Momentum along the major axis changes slowly with ellipticity.

Scaling laws for ellipticity dependence are established.

Abstract

We study ionization of atoms in strong elliptically-polarized laser fields numerically and analytically. We focus on effects of laser ellipticity on the offset angle in photoelectron momentum distribution. This angle is considered to encode time information of tunneling ionization in attoclock experiments. The calculated offset angle increases with the decrease of ellipticity but the momentum along the major axis of laser polarization related to this angle changes slowly, in agreement with experiments. With a Coulomb-included strong-field model, the scaling laws for ellipticity dependence of this angle and relevant momentum components are obtained, and the ellipticity dependence of Coulomb-induced ionization time lag encoded in this angle is also addressed.