Characterization of the optical properties of ArF laser irradiated Nd:YAG crystal

Nd:YAG crystal samples were irradiated by 100 pulses of ArF laser at 50 and 250 mJ/cm2 laser fluences and 1 and 50 Hz repetition rates. The UV–vis–NIR spectra of the samples before and after the irradiation show that optical absorption changed in the entire spectral range. Additional absorption spectra were obtained for determining possible annihilated and generated defects in the crystal structure. A 236 nm negative absorption band reveals that many oxygen vacancy centers of the crystal structure removed by 50 mJ/cm2 ArF laser irradiation. On the other hand, a small positive absorption band at 239 nm was observed related to F center generation in the crystal structure. The additional absorption spectral behavior of 250 mJ/cm2 irradiated sample was different and a continuum positive absorption band in the 239–350 nm spectral range was observed due to new defects generation in the crystal structure. It is proposed that it would be possible to optimize the crystal structure modification by controlling the laser irradiation parameters such as energy fluence, pulse number and repetition rate.