Third-order nonlinear and planar waveguide properties of TiO₂/organically modified silane hybrid films doped with different disperse red 1 content

TiO₂/organically modified silane organic–inorganic hybrid films doped with different disperse red 1 contents are prepared by combining a low-temperature sol–gel method and a spin-coating process. Effects of the disperse red 1 content on the third-order nonlinear and the planar waveguide properties of the hybrid films are also studied by a z-scan technique and a prism coupling technique. Results indicate that the nonlinear refractive index of the hybrid films is negative, whose magnitude is of the order of 10⁻⁸ esu for the measured samples. It is suggested that both the thermal effect and the photoisomerization process contribute to the third-order nonlinear optical properties of the hybrid films jointly. It is also found that the refractive index and the thickness of the hybrid films decrease with an increase of the temperature as the independent variable. In addition to, optical absorption properties of the hybrid films are characterized by UV–Visible spectroscopy. These results indicate that the as-prepared hybrid films are promising candidates for photonic applications.