EN
In the paper there are shown the changes in optical properties of TiO_2 thin films prepared by dc magnetron sputtering at different gas flow rates. We found that there is a drastic change in optical properties such as optical transmission, refractive index, extinction coefficient and optical band gap with the gaseous flow rate and composition. We observed an improvement in optical properties of the films that had been deposited at higher gaseous flow rate and at a certain gaseous composition.