title: Optical studies on electron beam evaporated lithium triborate films.
abstract: 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 (β~10(-2) cm/W) reveal (Z-scan technique) that the material has negative nonlinearity and self-focusing nature.
authors.affiliation: School of Physics, Bharathidasan University, Tiruchirappalli 620 024, India.
authors.forename: R
authors.initials: R
authors.lastname: Mohandoss
authors.forename: S
authors.initials: S
authors.lastname: Dhanuskodi
authors.forename: C
authors.initials: C
authors.lastname: Sanjeeviraja
mesh_terms: D001881:Borates / Q000737:chemistry*; D004553:Electric Conductivity; D004583:Electrons; D018020:Lithium Compounds / Q000737:chemistry*; D049449:Luminescence; D017711:Nonlinear Dynamics; D055620:Optical Phenomena; D012031:Refractometry; D013499:Surface Properties; D014835:Volatilization
chemical_list: D001881:Borates; D018020:Lithium Compounds; C021051:lithium borate