Laser damage studies in zinc (tris) thiourea sulfate: Nonlinear optical crystal

Abstract

We report on a detailed study of laser damage in a semiorganic nonlinear optical crystal, zinc (tris) thiourea sulfate using eight nanosecond laser pulses with a repetition rate of 10 Hz at wavelengths of 532 and 1064 nm. The damage morphology shows a correlation with the mechanical hardness anisotropy. The crystal shows a damage threshold measured to be 0.6±0.1 GW/cm2 for a single 532 nm laser pulse which reduces to 0.12±0.01 GW/cm2 as the number of shots is increased to 10 000. Single shot laser damage at 1064 nm wavelength shows an onset estimated to be about 3 GW/cm2. Multiple shots at 1064 nm result in laser ablation hindering the determination of a damage threshold. We suggest a possible role of negative thermal effects resulting in the high damage threshold observed in this crystal.

Effect of organic dopants on ZTS single crystals

“…In the case of EDTA-doped sample, the damage threshold is almost the same as that of undoped specimen as no significant difference is observed. This laser damage threshold value is comparable [25] with that of KTP (0.32 GW/cm 2 ) and KDP (0.3 GW/cm 2 ). This could be well understood by the fact that dopant incorporation into the crystal is almost nil and resultantly there is no measurable difference in the laser damage threshold.…”

Growth kinetics of zinc(tris)thiourea sulphate (ZTS) crystals

“…Salient features of ZTS include a comparable nonlinear optical coefficient (d 31 = 0.13, d 32 = 0.35 and d 33 = 0.23 pm/V) with that of KDP (d 14 = 0.39 pm/V). A wide acceptance angle, good transparency down to 290 nm and a single shot laser damage threshold of 3 GW/cm 2 at 1064nm, makes it a good candidate for nonlinear optical applications [1][2][3]. This crystal crystallizes in the non-centrosymmetric orthorhombic space group Pca2 1 (point group mm2) with lattice parameters a = 11.26 Å, b = 7.773 Å and c = 5.491 Å.…”

Structural, dielectric and optical properties of N-(2 chlorophenyl)-(1-propanamide) (NCP) single crystals

“…Optical damage in non-metals (dielectrics) may severely affect the performance of high power laser systems as well as the efficiency of optical systems based on nonlinear process and has therefore been subject to extensive research for some 30 years [27]. From this view point, we carried out laser damage threshold measurements on NCP crystal, expending a Q-switched Nd:YAG laser (operating in TEM 00 mode) of 20 ns laser pulses at a wavelength of 1064 nm.…”