Studies on third order nonlinear optical properties of Nickel Boro Phthalate NLO crystal

Single crystals of Nickel Boro Phthalate (NBP) are grown by the slow evaporation technique. The crystals are subjected to Single crystal x-ray diffraction to analyse the crystal lattice parameters, and the crystal structure is found to be triclinic. The presence of functional groups has been estimated qualitatively from the Fourier transform infrared spectroscopy and elemental analysis is done using the Energy dispersive x-ray spectral study. The UV-visible spectral studies indicate a broad window of transparency in the entire visible and infrared region and the fundamental frequency is determined to be 285 nm. Optical properties such as the dielectric constant, polarizability, susceptibility, optical and electrical conductivity are presented graphically. Third-order nonlinear parameters are evaluated by the Z scan technique using continuous wave 532 nm diode- pumped Nd:YAG laser. Closed aperture mode indicates the self-defocusing nature and negative nonlinearity of the crystal. Open aperture mode reveals the saturation absorption within the crystal. The nonlinear optical parameters such as nonlinear refractive index n₂, nonlinear absorption coefficient β and nonlinear susceptibility χ ⁽³⁾ are also determined. (paper)