Growth and characterization of L - Methionine Barium Bromide (LMBB) semi-organic crystal for optical limiting applications

Abstract

The semi-organic nonlinear optical single crystal was grown from an aqueous solution by a slow evaporation solution technique (SEST) at room temperature. The characterization of the crystal was made using single crystal x-ray diffraction analysis and it was found to be L-Methionine Barium Bromide (LMBB) crystallized in a monoclinic system with space group C2/c and the cell parameter values are a= 10.74Å, b= 7.39Å, c= 8.69Å, α = γ = 90°, β = 113.53°. The UV-Vis-NIR spectroscopic study revealed that the crystal has good optical transparency and a lower cut-off wavelength was found to be 246 nm and also evaluated linear optical properties such as extinction coefficient and reflectance. The luminescence behavior of LMBB has been analyzed by fluorescence (FL) spectral study. The presence of functional groups in the LMBB is confirmed by FT-IR and FT-Raman vibrational patterns. The hardness (Hv), Meyer’s index (n), elastic stiffness constant (C11), yield strength (σy), knoop hardness (Hk), fracture toughness (Kc), and brittleness index (Bi) were analyzed using Vickers microhardness tester. Dielectric behavior as a function of frequency was examined. The laser-induced damage threshold value was found to be higher than that of KDP. The surface morphology of the as-grown crystal was determined using the SEM technique. Energy dispersive X-ray analysis was used to determine the chemical composition of the LMBB crystal. The nonlinearity coefficient (β) is measured as 1.7 × 10−11 m/W using the open aperture Z-scan technique (Nd: YAG, 532 nm, 9 ns), which results from an effective two-photon absorption phenomenon. The resulting optical limiting behavior has a fluence threshold of 8.26 × 1012 W/m2 making the LMBB a potential candidate for optical limiting devices.