Nonlinear absorption and nonlinear refraction in single-phased Ti1−xInxO2 (x = 0∼0.1) thin films

Abstract

In this study, single-phased rutile T i 1 - x I n x O 2 ( x = 0 ∼ 0.1 ) thin films were deposited on fused quartz substrates using a pulsed laser deposition technique. The transmission spectra reveal that the films show good transparency in the wavelength range of 330–900 nm. The absorption edge of the T i 1 - x I n x O 2 thin films is blueshifted compared with that of undoped T i O 2 films. A single-beam z -scan method using a pulse laser operating at 532 nm with a duration of 55 ps was employed to evaluate the films’ nonlinear optical characteristics. The results show that the prepared T i 1 - x I n x O 2 films exhibit nonlinear saturable absorption and negative nonlinear refraction properties. The doping of In ions into T i O 2 does not change the nonlinear optical absorption significantly. However, the nonlinear refractive index of T i 1 - x I n x O 2 film obviously increases with the increasing doping of In ions. The local electron-pinned defect-dipoles and widening bandgaps in the T i 1 - x I n x O 2 thin films could be used to explain the observed results.