Three-dimensional Photonic Crystals Nonlinear Effects

In this dissertation we report the formation of photonic crystal of SiO,spheres with diamcter of 200 nm in ethonal, whose photonic gaP in the p -Ldirection varies with the height of crystal from 620 to 650 nm. lt has a face-centered-cubic (FCC) structure testified. by several methods. The Ramanscattering at 630 nm, induced by a 35ps second hamornic of YAG laser, ismeasured at different heights in the r -L direction. We fOund that the intensity ofthe Raman signaI does not change with the height, i.e. it is not related to the bandgap.Opal is created with polystyrene spheres whose diameter is 204 nm. The gaPcamer in the f -L direction is at 623 nm. The Raman scattering of polystyrene isju8t in 622 nm if it is excitated by an Ai+ laser in 496.5 nm. We also found theRaman signal does not related to the band gap.Some artificial Opals are also prepared and the scanning electronmicroscopy (SEM) shows that it is FCC. The change of the band gap was fOundwhen materials with different refractive index are penetrated.