Photoionization-induced reflection for benchmarking of the photoionization models in solid

TL;DR

This paper introduces a method to benchmark photoionization models in solids by analyzing reflected pulse waveforms, validated against TDDFT simulations, and provides a software tool for simulation, highlighting limitations of semi-classical models for ultrashort pulses.

Contribution

It presents a new benchmarking approach using reflected pulse waveforms and introduces the PIGLET software for photoionization simulations in solids.

Findings

The waveform analysis can determine the most suitable photoionization model.

PIGLET software enables accurate FDTD simulations of photoionization effects.

Semi-classical models fail for sub-10-fs pulses due to interband effects.

Abstract

The choice of the most suitable analytic photoionization model in solids is a challenging task with no default solution. Here we show how the best formalism can be determined based on the waveform of the pulse reflected by a sample due to photoionized almost-free electrons in the conduction band. For a typical case of diamond, we compare three simple models and benchmark them against highly accurate first-principle TDDFT simulation, by analysing the fit between the reflected pulses in time and frequency domain. For the aims of this paper, we have developed a software package, called PIGLET, for the FDTD simulation of photoionization-governed propagation, which is now freely available for the scientific community. Furthermore, we show that due to interband contributions for very short sub-10-fs pulses a semi-classical description based on any analytical photoionization model fail to provide an adequate description.