Physicochemical properties of cesium tetroxalate dihydrate single crystal: An efficient material for nonlinear optical applications

Herein we report the tunable optical limiting property of a metal–organic cesium tetroxalate dihydrate (CTD) complex. Temperature and pH were optimized to be 40°C and 3.5 respectively to grow CTD single crystal using the solvent evaporation method. The compound formation was confirmed by its response to single crystal and powder x-ray diffraction analysis. Thermal, mechanical, dielectric, linear optical, photoconductivity and photoluminescence properties of title crystal are reported. Nonlinear coupling between delocalized π-electrons of metal–ligand interaction and the oscillating electric field of a laser beam enhanced the nonlinear optical parameters. The third order nonlinear refractive index (n2), absorption coefficient (β) and susceptibility (χ(3)) of CTD complex under continuous-wave laser excitation are found to be (3.26±0.033)×10−8 cm2W−1, (10.33±0.41)×10−4 cmW−1 and (8.98±0.35)×10−5 esu respectively. Variation in two-photon absorption (2PA) coefficient measured under nanosecond pulsed laser excitation of different intensities confirmed the presence of sequential 2PA in CTD complex. The optical limiting threshold was investigated under different intensities were found to vary from (1.09±0.05)×1012 Wm−2 to (2.49±0.05)×1012 Wm−2 showing the intensity tunable optical limiting property of CTD material. •Alkali metal–organic single crystal for third order NLO applications is reported.•Intensity tunable optical limiting property of CTD was experimentally proven.•Sequential 2PA was conclusively proved from intensity-dependent β.•The optical switching behavior of CTD material was established.•Third order nonlinear optical susceptibility (χ(3)) of CTD is 8.98×10−5(esu).•The developed crystal was high stable mechanically and optically.