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Showing papers by "G. Vinitha published in 2015"


Journal ArticleDOI
TL;DR: In this article, the optical band gap of the?-BaB2O4 nanoparticle is estimated to be 59?eV and the presence of self trapped excitonic state (347?nm) was identified.
Abstract: Barium borate (?-BaB2O4) nanoparticles were prepared by a hydrothermal technique using barium chloride and boric acid as starting materials Powder x-ray diffraction confirms the pure single phase formation of ?-BaB2O4 Fourier transform infrared spectroscopy spectra shows the presence of BO3 units which extend themselves to form (B3O6)3? anionic groups in ?-BaB2O4 Scanning electron microscopy imaging shows the two-dimensional undulating particle surface with particle size in the range of 45?170?nm ?-BaB2O4 has strong absorption in the UV region and it possesses a wide optical transmittance window (201 to 1100?nm) The optical band gap of the ?-BaB2O4 nanoparticle is estimated to be 59?eV In the photoluminescence spectra the presence of self trapped excitonic state (347?nm) was identified The third order optical nonlinearity of the sample excited in two different pumping regimes, short pulse excitation (532?nm, 5?ns) and continuous wave laser (532?nm, 50?mW) was studied The material shows limiting behavior due to two photon absorption in the pulsed laser regime and self defocusing in the continuous wave regime

43 citations


Journal ArticleDOI
TL;DR: Thermogravimetric analysis and differential thermal analysis showed that the compound melts at 142.9°C, and the limiting behavior observed with the sample is attributed mainly to nonlinear refraction.

37 citations


Journal ArticleDOI
TL;DR: In this paper, the optical nonlinearity of metal complexes of p-nitrophenolate (M=Li, Na and K) in ethanol was studied by using a continuous wave (cw) diode pumped Nd:YAG laser (532nm, 50mW).
Abstract: Optical nonlinearity of metal complexes of p-nitrophenolate (M=Li, Na and K) in ethanol is studied by using a continuous wave (cw) diode pumped Nd:YAG laser (532 nm, 50 mW). The predominant mechanism of observed nonlinearity is thermal in origin. The nonlinear refractive index and the nonlinear absorption coefficient of the samples were found to be in the order of 10 −8 cm 2 /W and 10 −3 cm/W respectively. Magnitude of third-order optical parameters varies according to the choice of alkali metal chosen for metal complex formation of p-nitrophenolate. The third-order nonlinear susceptibility was found to be in the order of 10 −6 esu. The observed saturable absorption and the self-defocusing effect were used to demonstrate the optical limiting action at 532 nm by using the same cw laser beam.

36 citations


Journal ArticleDOI
TL;DR: FESEM reveals that the particles are coagulated and the particle size is in the range of 50-107 nm, and bands appear at 682-769 cm(-1) corresponds to the bending of B-O linkage in borate network.

20 citations


Journal ArticleDOI
TL;DR: The organic material 4-dimethylaminobenzaldehyde single crystals were grown by slow evaporation technique and the grown crystal was confirmed by the single crystal and powder X-ray diffraction analyses.

17 citations


Journal ArticleDOI
TL;DR: In this article, the authors reported the preparation of high purity ZnS nanoparticles by a facile single step solvent-free route via thermal decomposition of zinc acetate dihydrate and thiourea in air atmosphere.
Abstract: This paper reports on the preparation of high purity ZnS nanoparticles by a facile single step solvent-free route via thermal decomposition of zinc acetate dihydrate and thiourea in air atmosphere. The third-order optical nonlinearity of the prepared ZnS nanoparticles were measured by Z-scan technique using continuous wave 532-nm diode pumped Nd:YAG laser. From nonlinear optical (NLO) measurements, the prepared ZnS nanoparticles possess negative nonlinearity i.e., self-defocusing. Open aperture Z-scan measurement shows saturable absorption within the medium. These results show that the prepared ZnS nanoparticles are promising candidate for various potential applications in the field of nonlinear optics.

15 citations


Journal ArticleDOI
TL;DR: UV-Vis studies show that there is no strong absorption in the visible region of copper doped lithium tetraborate nanoparticles, and the relative powder second harmonic generation efficiency of pure and doped LTB is equal to the standard NLO material, KDP.

14 citations