A K Chaudhary

Study of laser induced damage threshold and effect of inclusions in some nonlinear crystals

Abstract The paper reports the comparative studies on the laser-induced single-shot and multiple-shot surface damage thresholds of nonlinear crystals, viz. Urea, 3-methyl-4-nitropyridine-1 oxide (POM), l -arginine phosphate (LAP) and β-barium borate (BBO) crystals. The measurements were made using radiation of 1064 nm and its second harmonic generation, i.e. 532 nm from a Q-switched Nd:YAG laser of pulse width 10 ns. In addition, the effect of Na+ impurity incorporated during growth in BBO crystal in different concentration (wt.%) has also been studied, and attempted to be correlated with various factors. We also measured the absorption coefficients of these crystals at different wavelengths. The Scanning Electron Microscope coupled with Energy Dispersive X-Ray Analyzer (SEM-EDX) has been employed to study the inclusions/impurities present in the crystals.

Generation of widely tunable mid-infrared radiation by difference frequency mixing in KTP

The crystal potassium titanyl phosphate (KTP) shows promise for generation of tunable infrared radiations throughout the range m. Widely tunable mid-infrared radiations have been generated by nonlinear difference frequency mixing of the Nd:YAG second harmonic and the same pumped tunable dye laser radiation (610 - 710 nm) in a KTP crystal. The system generates more than 14 W mid-infrared peak power at m by difference frequency generation.

Highly efficient difference-frequency generation in KTP

A conversion efficiency as high as 22%from dye-laser radiation to the near infrared with difference-frequency mixing of Nd:YAG laser radiation and its second-harmonic-pumped dye laser in an only 5 mm long KTP crystal is reported for the generation of tunable near infrared radiation.

Tunable mid-infrared generation in cesium lithium borate crystal

Abstract Generation of tunable mid-infrared radiation has been done in a cesium lithium borate (CsLiB 6 O 10 , CLBO) crystal for the first time employing type-I noncollinear difference frequency mixing of Q-switched Nd:YAG (or its second harmonic) and the tunable dye-laser radiation (0.605–0.725 μm). In the process a quantum conversion efficiency of ∼5.5% has been realized for the generation of 1.85 μm in only a 5 mm long crystal when the used peak power density of the pump dye-laser (0.675 μm) beam is as low as 12.7 MW/cm 2 .

Type-I walk-off compensated second and fourth harmonic generation of Nd:YAG laser radiation from a Li2B4O7 crystal

A type-I walk-off compensation (WOC) arrangement has been made for the second harmonic generation (SHG) and the fourth harmonic generation (FOHG) of commercially available Q-switched Nd:YAG laser radiation, for the first time, using two identically cut Li2B4O7 crystals. The enhancement of the conversion efficiencies has been realized in the WOC arrangement by a factor of 2.71 for the SHG and 2.65 for the FOHG relative to the double-crystal non-walk-off arrangement. The absolute values of the conversion efficiencies obtained for WOC SHG and FOHG are 3.52% and 3.56% respectively, applying input power densities for the fundamental and second harmonic of the Nd:YAG laser beam at only 28.3 MW cm-2 and 11.7 MW cm-2, respectively.

The generation of efficient tunable coherent near-IR radiation by temperature-tuned non-critical difference-frequency mixing in a LBO crystal

Efficient tunable near-infrared radiation (NIR) () has been generated by temperature-tuned non-critical phase-matched (NCPM) difference-frequency mixing of Nd:YAG and tunable dye laser radiation (560 - 710 nm) in a 5 mm LBO crystal. Energy conversion efficiency of 11% at 1.54 has been achieved. A large angular and spectral bandwidth is observed. Temperature-tuned type-II non-collinear phase-matching has also been reported. Comparison with other NIR-generating crystals shows that temperature-tuned NCPM in LBO is superior to other methods.