Optical properties of Bi_(2.25)La_(0.75)TiNbO_9 thin films grown on fused silica substrates by PLD

摘要

Layered-perovskite ferroelectric Bi_(2.25)La_(0.75)TiNbO_9 (LBTN-0.75) optical waveguiding thin films have been prepared on fused silica substrates by pulsed laser deposition (PLD). X-ray 0-20 scans revealed that the films are single-phase perovskite. The optical properties, such as the wavelength dependence of the transmittance and the refractive index, were determined. The average transmittance of the film is 75% in the wavelength range of 200-1100 nm and the band gap E_g = 3.46 eV. The optical waveguiding properties of the films were characterized by using prism coupling method. The distinct m-lines of the guided transverse electric (TE) and transverse magnetic (TM) modes of the LBTN-0.75 films waveguide have been observed. The film homogeneity and the film-substrate interface were analyzed using the inverse Went-zel-Kramer-Brillouin (iWKB) method.