Effect of Annealing on the Tolerance of LiCaAlF₆ Single Crystals against F₂ Laser Irradiation

Abstract

The optical tolerance of annealed LiCaAlF6 single crystals against F2 laser irradiation was investigated. Annealed LiCaAlF6 (t=1.45 mm) shows an improved transmittance at 157 nm, 94.4% after the compensation of the surface reflection loss. Furthermore, after the initial increase by F2 laser cleaning, transmittance at 157 nm remains almost unchanged even after irradiation with a F2 laser beam up to 105 pulses at a fluence of approximately 160 mJ cm-2 pulse-1.

<title>F<formula><inf><roman>2</roman></inf></formula>-laser-induced damage on transparent fluoride crystals</title>

“…Moreover, the annealed LiCaA1F6 (C plane, t = 1.45 mm) also showed almost no change of the transmittance at ? = 157 nm [28].…”

“…In this report, we examined optical tolerance ofthese crystals against F2 laser irradiation to clarify if they can be the candidates of the "second material" to combine with CaF2 for F2 laser optics. We investigated the change of the VUV transmittance by cumulative F2 laser irradiation, the evaluation of threshold fluence of optical breakdown and initiation ofF2 laser ablation, and the morphology ofthe F2-laser-damaged surfaces ofthese crystals [26][27][28].…”

Backside etching of fused silica with Nd:YAG laser

“…Nevertheless, the application potential is very high as different studies show that demonstrate the high quality patterning of surfaces, the etching of refractive and diffractive patterns, the etching of deep trenches, and the patterning for live science application [1][2][3][9][10][11][12]. Therefore, further investigations aim to increase efficiency, speed, and reliability with preserving the quality of the etched surface.…”