Preparation and optical properties of cobalt doped lithium tetraborate nanoparticles

Lithium tetraborate doped with cobalt ions of different concentrations were synthesized by chemical method and characterized by X-ray. Field emission scanning electron microscopy reveals the spherical morphology of the nanoparticles and the average particle size is estimated to be 50-110 nm. UV-Vis studies show the inclusion of Co2+ and the lithium-vacancy pair production. The samples are completely transparent in the visible region and having absorption peak (220 nm) in UV region. Nonlinear optical studies indicate the suitability of pure and Co2+ doped samples for low power optical limiting and frequency doubling applications. From the Z-scan technique, the nonlinear optical parameters such as nonlinear refractive index, nonlinear absorption and nonlinear optical susceptibility are estimated as 10−8 cm2/W, 10−2 cm/W and 10−5 esu respectively.