Filamentation of ultrashort laser pulses in silica glass and KDP crystal: A comparative study

TL;DR

This study compares the filamentation of ultrashort laser pulses in silica glass and KDP crystal, revealing similarities in propagation dynamics despite differences in filament characteristics and plasma properties.

Contribution

It provides a comparative analysis of laser filamentation in silica and KDP, including effects of defect states and electron-hole dynamics, using a unidirectional pulse propagation model.

Findings

KDP filaments reach higher intensities and longer plasma channels.

Propagation dynamics are similar in silica and KDP at equivalent power ratios.

KDP exhibits electron densities above 10^{16} cm^{-3}.

Abstract

Ionizing 800-nm femtosecond laser pulses propagating in silica glass and in potassium dihydrogen phosphate (KDP) crystal are investigated by means of a unidirectional pulse propagation code. Filamentation in fused silica is compared with the self-channeling of light in KDP accounting for the presence of defect states and electron-hole dynamics. In KDP, laser pulses produce intense filaments with higher clamping intensities up to 200 TW/cm$^2$ and longer plasma channels with electron densities above $10^{16}$ cm$^{-3}$. Despite these differences, the propagation dynamics in silica and KDP are almost identical at equivalent ratios of input power over the critical power for self-focusing.