Temperature Dependent Optical Properties of c axis Oriented LiNbO $_{3}$ Thin Film Using Surface Plasmon Resonance

A prism coupling based Surface Plasmon Resonance (SPR) technique, assembled in the laboratory, has been employed to study the optical properties of highly (006) oriented LiNbO₃ thin film in Kretschmann-Reather configuration. A (006) oriented LiNbO₃ film with c axis normal to the substrate surface is deposited at a substrate temperature of 500°C on the face of BK7 glass prism using (002) ZnO buffer layer. The SPR data on oriented LiNbO₃ thin film is measured over a wide range of temperature (300 to 573 K) at 633 nm wavelength. No report is available in the literature on the temperature dependent optical and dielectric properties of c axis oriented LiNbO₃ thin film at optical frequency. Complex dielectric constant of the film is obtained in the present study by fitting the experimental SPR data with theory. The linear change in the refractive index and dielectric constant of the as grown (006) LiNbO₃ thin film with temperature (300-573 K) indicates the importance of SPR technique in probing temperature dependent optical properties of a thin film and shows the promising application of prepared multi-layered structure on prism as effective temperature sensor.