Band gap Engineering and scaling of laser induced surface damage threshold properties of N,N′-Diphenylguanidinium based single crystals by organic and inorganic acids for nonlinear optic applications

Crystals with high optical band gap and laser damage threshold have attracted much interest in the field of nonlinear optical applications. New and efficient organic nonlinear optical crystals of N,N'-Diphenylguanidinium compounds were synthesized and grown by solvent evaporation technique. The grown crystals were subjected to X-ray diffraction study for structural confirmation. The UV-vis-NIR transmittance spectra were recorded, and from these transmittance data the optical band gap and optical conductivity were calculated. The second harmonic generation (SHG) nonlinearity of the grown crystal was measured by Kurtz and Perry powder technique and was found to be comparable with that of the standard reference material, potassium dihydrogen phosphate (KDP) crystal. The laser induced surface damage threshold study for the grown crystals was carried out using Nd:YAG laser. It is well observed from these optical and laser induced surface damage threshold studies that the band gap and damage threshold properties can be tuned by the replacement of the functional group in the compounds.