Influence of lithium ions on the NLO properties of KDP single crystals

Study on optical properties of l-valine doped ADP crystal

Single crystal of l-valine doped ammonium dihydrogen phosphate has been grown by slow evaporation method at room temperature. The crystalline nature of the grown crystal was confirmed using powder X-ray diffraction technique. The different functional groups of the grown crystal were identified using Fourier transform infrared analysis. The UV-visible studies were employed to examine the high optical transparency and influential optical constants for tailoring materials suitability for optoelectronics applications. The cutoff wavelength of the title crystal was found to be 280nm with wide optical band gap of 4.7eV. The dielectric measurements were carried to determine the dielectric constant and dielectric loss at room temperature. The grown crystal has been characterized by thermogravimetric analysis. The second harmonic generation efficiency of the grown crystal was determined by the classical Kurtz powder technique and it is found to be 1.92 times that of potassium dihydrogen phosphate. The grown crystal was identified as third order nonlinear optical material employing Z-scan technique using He-Ne laser operating at 632.8nm.

Studies on influence of Cd(2+) ions in unidirectional growth and characterization of l-Cysteine hydrochloride monohydrate single crystals

Cadmium doped l-Cysteine hydrochloride monohydrate (Cd(2+)-C3H7NO2S⋅HCl⋅H2O), a non-linear optical crystal, was grown by conventional as well as unidirectional solution growth techniques. While the dimension of the conventionally grown crystal was 16×14×5mm(3), the dimension of the crystal grown unidirectional method was 32mm long and 6mm diameter. The grown crystals were studied using XRD for phase analysis, HRXRD for crystalline perfection and UV-Vis NIR spectroscopy for optical properties. The high crystalline perfection was found in the crystal grown by unidirectional method than that grown by conventional one. FTIR study indicates that Cd(2+) ion was coordinated to l-Cysteine⋅HCl⋅H2O through S ligand. The nonlinear optical character of the title compound was observed by measuring the SHG efficiency, which is 1.35times to that of KDP by Kurtz technique.

Growth, structural, spectral, mechanical and optical properties of pure and metal ions doped sulphamic acid single crystals

Bulk single crystals of pure and metal ions (Mn(2+), Cu(2+) and Ni(2+)) doped sulphamic acid (SA) have been grown by conventional and unidirectional solution growth methods. Intensities of powder X-ray diffraction peaks of metal ions doped SA reveal that these dopants enhanced the crystallanity. The peak broadening and intensity variation in some frequency regions in FT-IR spectra show the incorporation of dopants in the SA lattice. Mn(2+) and Cu(2+) doped SA single crystals show high crystalline perfection (FWHM 5.5arcs) compared to pure and Ni(2+) metal ions doped SA crystals. The grown pure and Mn(2+), Cu(2+) and Ni(2+) ions doped SA crystals have transparency in the order SA>Mn:SA>Cu:SA>Ni:SA. The hardness value of Ni(2+) doped crystal is relatively less than that of the pure and other metal ions doped SA crystals. Pure and Ni(2+) ions doped SA crystals possess high dielectric constants than that of Cu(2+) and Mn(2+) ions doped crystals. From the SEM micrograph analyses, it is observed that the doping of these metal ions modify the surface morphology of the grown crystals.