JOURNAL OF THE KOREAN PHYSICAL SOCIETY, v. 49, No. 3, Page. 938-942
A TiO2 optical thin film is fabricated by use of a sol-gel method. The structure of the TiO2 thin film is examined by using an X-ray diffraction measurement, which shows that the gelation process at 500 degrees C results in an anatase phase. A nonlinear optical transmission measurement is performed by pumping near the energy gap edge of the TiO2 thin film. The nonlinear optical responses of the d- and the sp-orbitals are found to be responsible for the large optical Kerr nonlinearity in the anatase TiO2 thin film.