Strong Field Ionization Rate for Arbitrary Laser Frequencies

Abstract

A simple, analytical, nonrelativistic ionization rate formula for atoms and positive ions in intense ultraviolet and x-ray electromagnetic fields is derived. The rate is valid at arbitrary values of the Keldysh parameter and confirmed by results from ab initio numerical solutions of the single active electron, time-dependent Schrödinger equation. The proposed rate is particularly relevant for experiments employing the new free electron laser sources.

Analytical model for calibrating laser intensity in strong-field-ionization experiments

“…The KFR theory is known to be unable to correctly predict absolute ionization probability, yet it does predict fair intensity dependence. Over the years, beginning with the original Perelomov-PopovTerent'ev (PPT) theory [44][45][46], various corrections have been introduced and extended to molecules as well [10,[47][48][49][50]. We comment that there are other ionization theories, such as the nonadiabatic tunneling ionization (NTI) [51] theory, the weak-field asymptotic theory (WFAT) [52][53][54][55][56], and so on.…”

“…We comment that there are other ionization theories, such as the nonadiabatic tunneling ionization (NTI) [51] theory, the weak-field asymptotic theory (WFAT) [52][53][54][55][56], and so on. We will focus on the newer version of the PPT theory [47], which offers simplicity and proven accuracy. It also gives cycle-averaged ionization rates analytically.…”

“…In this work, we first evaluate the improved PPT model [47], which includes a more accurate Coulomb correction term. Our main goal here is to show that within a tolerable error this version of the PPT model can be efficiently and conveniently used by experimentalists to retrieve accurate peak laser intensity from measured ionization signals.…”

Interpretation of negative birefringence observed in strong-field optical pump-probe experiments: High-order Kerr and plasma grating effects

“…Such a modelling, which remains a challenging task, has been the subject of numerous theoretical works [35][36][37][38]. In particular, it has been shown [39] that the ionization model first developed by Perelomov Popov and Terent'ev (PPT) reproduces well the experimental measurements performed in conditions close to the ones used in the present paper.…”

Exchange and polarization effect in high-order harmonic imaging of molecular structures

“…For example, it opens a route to following attosecond dynamics of holes between ionization and recombination [15][16][17][18]. However, the drawback is the need for accurate theoretical description of strong-field dynamics, starting with strong-field ionization, for both single [20][21][22][23][24][25][26][27][28] and multiple ionization channels [29][30][31]. Quantitative modeling of harmonic generation requires one to consider not only multiple ionization and recombination channels corresponding to different states of the molecular ion, but also their coupling during strong-field ionization and between ionization and recombination [13,15,32].…”