We report on linear transmittance and reflectance as well as on third-harmonic generation in photonic crystal alloys formed by various compositions of polystyrene and poly (methyl methacrylate) colloidal spheres of the same size. These photonic crystal alloys are structurally ordered but contain refractive-index disorder and thus provide a random variation of scattering potential. The stopgap shows a monotonic shift in wavelength as a function of composition that can be fitted by assuming an effective dielectric constant for the colloidal spheres. In each alloy a dramatic enhancement of third-harmonic generation is observed, always on the short-wavelength side of the stopgap.
© 2004 Optical Society of America
Hanifi Tiryaki, Koichi Baba, Przemyslaw P. Markowicz, and Paras N. Prasad, "Linear and nonlinear optical studies in photonic crystal alloys," Opt. Lett. 29, 2276-2278 (2004)