Multiphoton Ionization of Magnesium in a Ti-Sapphire laser field

TL;DR

This paper presents theoretical calculations of magnesium ionization and ATI spectra in a Ti:sapphire laser field, comparing two computational methods to analyze ionization yields and spectra for different pulse durations.

Contribution

It introduces and compares two nonperturbative computational approaches for modeling magnesium ionization in intense laser fields, highlighting their respective advantages and limitations.

Findings

Ionization yield depends on laser intensity and pulse duration.

The open-channel method effectively handles multiple continua in ionization.

Results align with recent experimental data for 120 fs pulses.

Abstract

In this paper we report the theoretical results obtained for partial ionization yields and the above-threshold ionization (ATI) spectra of Magnesium in a Ti:sapphire laser field (804 nm) in the range of short pulse duration (20-120 fs). Ionization yield, with linearly polarized light for a 120 fs laser pulse, is obtained as a function of the peak intensity motivated by recent experimental data \cite{gillen:2001}. For this, we have solved the time-dependent Schr\"{o}dinger equation nonperturbatively on a basis of discretized states obtained with two different methods; one with the two-electron wavefunction relaxed at the boundaries, giving a quadratic discretized basis and the other with the two-electron wavefunction expanded in terms of Mg$^+$-orbitals plus one free electron allowing the handling of multiple continua (open channels). Results, obtained with the two methods, are compared and advantages and disadvantages of the open-channel method are discussed.