Optical properties of vanadyl phthalocyanine thin films and nonlinear refractive index of vanadyl phthalocyanine doped PMMA by using thermal lens spectrometry technique

Abstract

The optical properties of vanadyl phthalocyanine (VOPc) thin films have been studied in the spectral range 300-900 nm. Variations in the optical constants with wavelength are found to be thickness dependent of the films. The optical band gap E_g and optical conductivity ?_opt were determined. The analysis of the optical absorption data indicates that the optical band gap Eg was indirect transitions. The optical band gap of the VOPc thin films was found to increase with thickness of the film. According to Wemple and DiDomenico method, the optical dispersion parameters E_o and E_d were determined. Thermal lens spectrometry is applied to measure the thermo-optic coefficient dn/dT and nonlinear refractive index for VOPc doped Poly methylmeth acrylate (PMMA) film. The measurements were carried out using the SDL laser at wavelength 635 nm, as both probe and excite source.

Keywords: Thin film, Optical constants, Nonlinear refractive index, Thermal lens spectrometry