TiO_2 nanoceramic films prepared by ion beam assisted evaporation for optical application

摘要

A TiO_2 nanoceramic film was prepared as an alternative absorber layer for infrared thermal detectors. The TiO_2 film was amorphous, and its grain size increased with the ion anode voltage and oxygen flow rate. Moire deflectometry was applied for measuring the nonlinear refractive indices of TiO_2 films on polycarbonate (PC) substrates. The nonlinear refraction index was measured to be of the order of 10~(-8) cm~2 W~(-1) and the change in refractive index was of the order of 10~(-5). The linear refractive index was correlated with the porosity. Denser TiO_2 films exhibited higher linear refractive indices, obvious red-shifts and narrower absorption bands in the near-IR region.