Synthesis,growth, and two-photon absorption induced optical limiting action of cytosinium benzoate single crystal

Two-photon absorption induced optical limiting action was demonstrated in cytosinium benzoate (CB) under nanosecond laser (532 nm, 9 ns, and 10 Hz) excitation. Intensity dependent open aperture Z-scan experiment exposed the presence of reverse saturable absorption ascribed due to sequential two-photon absorption. Initially CB single crystals were grown at room temperature by slow evaporation solution technique. Single crystal XRD shows that CB belongs to monoclinic crystal system with P2₁/c space group. Fourier Transform Infrared spectrum was recorded to identify the presence of functional groups. Thermal studies shows that the crystal is stable upto 168 °C. Vickers microhardness studies confirm that the grown crystal was belongs to soft material category. Etching study shows linear rectangular etch patterns (5 s) and well defined stacking planes (10 s) for water etchant. Optical studies demonstrate that CB crystal possess lower cut-off (287 nm) and moderate linear transmittance in visible region. The optical energy band gap of CB crystal was estimated from photoluminescence studies as 3.1 eV. CB with higher two-photon absorption coefficient (1.26?×?10^–10 m/W) and lower onset limiting threshold (1.92?×?10¹² W/m²) can be a potential candidate for developing laser safety devices under nanosecond green laser excitation regime.

     

Laser damage threshold,antimicrobial efficacy and physicochemical properties of an organometallic L-proline lithium chloride monohydrate single crystal for NLO application and optoelectronic device fabrication

The potential metalorganic L-proline lithium chloride monohydrate single crystal was grown by slow evaporation method for evaluating optoelectronic device fabrication. From the single crystal XRD studies, the grown crystal was confirmed the molecular packing in monoclinic crystal lattice. The powder XRD data confirm the phase purity of the grown crystal. Vibrational absorption band assignments were recognized by FTIR and FT-Raman spectrum and they confirmed the presence of multiple functional groups in the grown crystal structure. Optical properties of the grown crystal were studied by using transmittance and absorption spectrum of UV–Vis–NIR analysis. The dielectric response of the grown crystal was studied in the frequency range between 50 Hz and 2 MHz for four temperature gradients. From the microhardness study, some mechanical parameters such as fracture toughness, brittleness index and yield strength were calculated. The photoluminescence activity of the grown crystal was deliberate in terms of optical peaks. The amino group participation over the optical scattering nodal regions for generating radiation absorption process to fascinate optical endurance was studied. TG/DTA curve shows that the LPLCM crystal was thermally stable up to 132 °C. The laser damage threshold value of the grown crystal was measured using multishot mode and it was found to be 7.78 GW/cm². The fractionation of the etching time prevents lattice from over etching and degradation of the mechanical properties of the grown crystal. LPLCM crystal showed higher antibacterial activity against one gram positive and one gram negative bacterial species. Second order nonlinear optical efficiency of the LPLCM crystal was studied at 1064 nm generated by a nanosecond pulsed Nd:YAG laser source.