Effect of Dopants on Laser-Induced Damage Threshold of ZnGeP2

Abstract

The effect of doping Mg, Se, and Ca by diffusion into ZnGeP2 on the optical damage threshold at a wavelength of 2.1 μm has been studied. It has been shown that diffusion-doping with Mg and Se leads to an increase in the laser-induced damage threshold (LIDT) of a single crystal (monocrystal), ZnGeP2; upon annealing at a temperature of 750 °C, the damage threshold of samples doped with Mg and Se increases by 31% and 21% from 2.2 ± 0.1 J/cm2 to 2.9 ± 0.1 and 2.7 ± 0.1 J/cm2, respectively. When ZnGeP2 is doped with Ca, the opposite trend is observed. It has been suggested that the changes in the LIDT depending on the introduced impurity by diffusion can be explained by the creation of additional energy dissipation channels due to the processes of radiative and fast non-radiative relaxation through impurity energy levels, which further requires experimental confirmation.

Physical and Technological Aspects of Laser-Induced Damage of ZGP Single Crystals under Periodically Pulsed Laser Irradiation at 2.1 μm

“…However, the prolonged operation of powerful OPOs and OPGs/OPAs based on ZGP is limited by the laser-induced damage (LID) of this material. In accordance with the results of numerous studies [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48], the ZGP LID always occurs at the sample surface or in the sub-surface layer rather than in the bulk in samples subjected to repetitively pulsed nanosecond-pulse-width infrared radiation. A combination of factors associated with defects in the crystal structure in the sub-surface layer and the quality of polishing of the surface itself affects the LID.…”

“…There have been a number of publications on the problem of the ZGP LID induced by lasers operating at wavelengths from 1.064 µm to 10 µm [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. These studies have revealed a significant difference in the LIDT of ZGP crystals at wavelengths of 1.064 µm and 2.1 µm [31].…”

“…Dependence of the probability of optical damage on the energy density of the incident laser radiation with a wavelength of 2.1 µm in undoped samples (a), and in doped samples with Mg (b), Se (c), and Ca (d). Approximate plots in black and red correspond to ZGP samples annealed at 750 • C and 650 • C, respectively (adapted from[39]).…”

Barium Chalcogenide Crystals: A Review

“…The technologies for growing and processing these crystals are highly advanced. However, ongoing research efforts focus on improving the optical characteristics of these crystals through the incorporation of dopants during growth or through specific post-growth treatments [35][36][37]. Among these nonlinear materials, only the AGS crystal is suitable for the frequency down-conversion of the commonly used 1 µm solid-state laser to the mid-IR range.…”

Investigation of ZnGeP2 crystals by Raman spectroscopy and machine learning

“…The change in the LIDT threshold of a ZnGeP2 single crystal was achieved by diffusion doping of Mg, Se, and Ca into the single crystal, with Mg and Se leading to an increase in LIDT, and Ca, to a decrease in LIDT. [14] The goal of this paper is to verify the possibility of creating a sputtering detection system for ZnGeP2 crystals based on Raman spectroscopy combined with PCA-SVM analysis.…”