Optical properties of highly C-oriented Bi₃TiNbO₉ thin films grown on fused silica substrates by PLD

Abstract

Highly textured perovskite Bi₃TiNbO₉ (BTN) thin films have been fabricated on fused silica substrates using pulsed laser deposition (PLD). Film surface and structural properties were measured by using atomic force microscopy (AFM) and X-ray diffraction. The optical properties, such as the wavelength dependence of the transmittance and the refractive index, were determined. A band gap of E_g=3.55 eV was obtained experimentally. Optical properties were characterized by using a prism-coupling technique. We observed sharp and distinguishable transverse electric (TE) and transverse magnetic (TM) multimodes and measured the refractive indices of BTN thin films at 632.8 nm. The ordinary and extraordinary refractive indices were calculated to be n_o=2.3528 and n_e=2.3942. This means a birefringence of Δn=n_e-n_o=0.0414 for BTN films. These results show the potential of using BTN films as an electro-optical active material.