Low power optical limiting studies of copper doped lithium tetraborate nanoparticles

The copper doped lithium tetraborate (LTB:Cu) nanoparticles were synthesized by sol-gel method and characterized by XRD (tetragonal structure) and by FESEM (sphere-like nanoparticle). UV-Vis studies show that there is no strong absorption in the visible region. In the luminescence spectrum, the emission peak at 370 nm reveals the presence of Cu+ in LTB lattice. The relative powder second harmonic generation efficiency of pure and doped LTB is equal to the standard NLO material, KDP. The nonlinear optical parameters of LTB:Cu nanoparticles say, nonlinear refractive index, nonlinear absorption coefficient and third order nonlinear optical susceptibility were determined to be of the order of 10(-8)cm2/W, 10(-2) cm/W and 10(-5) esu, respectively. The optical power limiting behavior of the samples were studied by Z-scan technique with (532 nm, 50 mW) Nd:YAG laser and the limiting threshold values are found to be 22.7 mW for 0.01 M and 24.9 mW for 0.03 and 0.05 M LTB:Cu nanoparticles.