Luminescent photonic crystals

Angular distribution of photoluminescence of trivalent rare earth ions embedded inside three-dimensional opal and inverse opal photonic crystals is experimentally shown to be strongly modulated for the emission frequencies near the first and higher photonic stop-bands. Numerical simulations of fractional density of optical states also predict highly directional emission from photonic crystals with an ideal structure. Experimental results are shown to be in a good agreement with calculated angular dependencies of luminescence. However, better agreement between experimental and theoretical data requires smoothing of calculated dependencies, which can be attributed to the presence of structural imperfections in real photonic crystal samples.