Second harmonic generation and laser damage studies in zinc (tris) thiourea sulfate crystals

摘要

As a result, we conducted laser damage studies using 8 ns pulses at 10 Hz repetition rate at 532 and 1064 nm generated from an Nd:YAG laser. Figure 2 shows the laser damage threshold at 532 nm as a function of the number of pulses. The trend observed is similar to the earlier reported studies. Single shot damage occurs at 0.6 GW/cm{sup}2 while for 10,000 shots the value reduces to 0.12 GW/cm{sup}2. At 1064 nm, the single shot laser damage occurs at ～3 GW/cm{sup}2 and shows distinct signs of laser ablation with multiple shots, in contrast to previous picosecond studies. The measured damage threshold is comparable to that of Potassium Titanyl Phosphate (KTP) and BBO. This relatively high threshold is possibly the result of the presence of a negative thermal lens that compensates somewhat Kerr self-focusing effects. Furthermore, observed laser damage breakdown paths along specific crystallographic directions indicate the existence of a correlation between laser damage and mechanical hardness anisotropy. This study indicates that ZTS is a suitable candidate for SHG of fundamental sources in the sub-micron NIR spectral region.