We have observed strongly modified spontaneous-emission spectra from laser dye in photonic crystals made of inverse opals in titania (TiO2). We identify stop bands with large relative widths of 15%, comparable to the dyes' emission spectrum, and 75% attenuation of the emission strength. For a wide range of angles, two stop bands are simultaneously manifested; their angle-dependent frequencies display an avoided crossing that is corroborated by reflectivity experiments. The edges of the stop bands agree well with band-structure calculations, but differ from simple Bragg diffraction as a result of multiple wave coupling. The strongly reduced dispersion of the Bloch modes likely causes a significant change in the density of states.
|Number of pages||4|
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - 1 Jan 2001|