Optical properties of non-stoichiometric titanium oxides

Optical properties of non-stoichiometric titanium oxides TiO$_{2-\delta}$ with different magnitude of deviation from stoichiometry $\delta$ have been investigated. The films were synthesized by ion-beam sputtering deposition method. The composition of the films was determined by X-ray photoelectron spectroscopy. The relationship between the optical parameters $(n, k)$ of the films and their composition $\delta$ has been established. It was found that annealing of the films of the composition $\delta\sim$ 0.58 $\pm$ 0.02 at temperatures 350–600С leads to a significant increase in absorption in the THz regions of the spectrum due to the growth of micron-sized plate-shaped crystals in the films, according to the data of scanning electron microscopy.