JOURNAL OF THE KOREAN PHYSICAL SOCIETY, v. 49, No. 5, Page. 2128-2131
the picosecond nonlinear optical response in five-bilayered SiO2/TiO2 structures of one-dimensional photonic crystals fabricated by using a sol-gel method is reported. We observe nonlinear optical changes in the transmission at both bandgap edges, an 8 % decrease at the high-energy edge, and a 4.5 % increase at the low-energy edge. These changes correspond to a blue shift of the bandgap. The observed reponse originates from the optical nonlinearity of the TiO2 layer.