Photoinduced refractive index changes in organic polysilane-inorganic hybrid thin films

Ultra-violet (UV) light induced refractive index change has been observed in organic polysilane (PS)-silica and PS-titania hybrid thin films prepared by a sol-gel method. The magnitude of refractive index change is found to be extremely large; 0.16 for 50 wt% PS-silica and 0.18 for 50 wt% PS-titania hybrid thin films. It is demonstrated that the refractive index change of the hybrid thin films is due to photodecomposition of PS. These findings indicate potential usefulness of the hybrid thin films as optical devices with refractive index modulated structures.