RESUMEN
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.
Asunto(s)
Boratos/química , Cobre/química , Nanopartículas/química , Luminiscencia , Nanopartículas/ultraestructura , Transición de Fase , Espectrofotometría Ultravioleta , Difracción de Rayos XRESUMEN
Manganese doped Li2B4O7 nano crystallites were prepared by chemical method and characterized by XRD, FTIR, UV and fluorescence spectra. FESEM reveals that the particles are coagulated and the particle size is in the range of 50-107 nm. Bands appear at 682-769 cm(-1) corresponds to the bending of B-O linkage in borate network. Nonradiative energy transfer process is observed from fluorescence spectrum. UV-Vis studies show the samples are completely transparent in the visible region and having absorption peaks (234 and 276 nm) in UV regime. The measured second harmonic generation values are 0.9 times KDP. The nonlinear optical parameters such as nonlinear refractive index, n2 (10(-8) cm(2)/W), nonlinear absorption, ß (10(-2) cm/W) and nonlinear optical susceptibility, χ(3) (10(-5) esu) are estimated using a Nd:YAG laser (532 nm, 50 mW).
Asunto(s)
Boratos/química , Manganeso/química , Nanopartículas/química , Fenómenos Ópticos , Luminiscencia , Nanopartículas/ultraestructura , Dinámicas no Lineales , Polvos , Espectrometría de Fluorescencia , Espectrofotometría Ultravioleta , Espectroscopía Infrarroja por Transformada de Fourier , Difracción de Rayos XRESUMEN
Lithium triborate (LB3) has numerous applications in scintillator for neutron detection, laser weapon and communication. LB3 films have been prepared by electron beam evaporation technique under a pressure of 1×10(-5) mbar on glass substrate at 323 K for 4 min. The crystallographic orientations and the lattice parameters (a=8.55 (2); b=5.09 (2); c=7.39 (2)Å) were determined by powder XRD indicating the (111) preferential orientation of the film. The lower cut off wavelength at 325 nm with 75% transparency was measured from the UV-vis spectrum. The optical constants extinction coefficient (K), reflectance (R), the linear refractive index (1.34) and the optical energy band gap (~4.0 eV) were estimated. The photoluminescence spectrum shows the emission peak in the visible region with low concentration of oxygen defects. LB3 is found to be second harmonic generation (SHG) active using a Q-switched Nd:YAG laser (1064 nm, 9 ns, 10 Hz). The nonlinear refractive index (n(2)~10(-16) cm(2)/W) and nonlinear absorption coefficient (ß~10(-2) cm/W) reveal (Z-scan technique) that the material has negative nonlinearity and self-focusing nature.