A novel photonic crystal in which the refractive index of the interstitial void region in a colloidal crystal is gradually changed with respect to the specific direction of the crystal was proposed. This was achieved by infiltrating polymers using the interfacial-gel polymerization with high refractive index dopants. Therefore, the resulting colloidal photonic crystal has a gradually varying stop-band at different positions of the crystal when the incident light was normal to the  crystallographic axis. This structure could be a kind of tunable photonic crystals based on the positional variations. The optical properties and potentials for other photonic applications will be investigated.
High bandwidth graded index plastic optical fiber was fabricated by the centrifugal deposition method. A preform for graded index plastic optical fiber (GI-POF) was fabricated by the centrifugal deposition method. In the method mixture of two monomers having different refractive indices is fed into a rapidly rotating tube in an oven, The mixture forms a thin layer on the tube wall due to the centrifugal force and polymerize simultaneously by thermal reaction. By changing the composition of the feeding monomer mixture as a programmed way, the refractive index of the preform can be controlled in the radial direction as programmed. Methyl methacrylate (MMA) and benzyl methacrylate (BzMA) were used as the monomers. The GI-POF was obtained by thermal drawing of the preform. The refractive index profile of the drawn fiber was the same as the preform. The optical loss of the GI-POF was 120 dB/km and the bandwidth was 3.45 Gbps100m at the wavelength of 650 nm.