Emission properties of dye-polymer-opal photonic crystals

The effect of the incomplete photonic bandgap (PBG) provided by the opal te mplate upon the emission properties of the laser dyes (Coumarin 6 and peryl ene derivative) dissolved in the solidified polymer has been studied. The b andgap of dye-polymer-opal composite is highly anisotropic because of the i nsufficient refractive index contrast (RIC), moreover, the extent of anisot ropy depends on the volume fraction of the polymer, The anisotropic bandgap enforces the corresponding directionality of the emission, but the emissio n anisotropy is-restricted, as compared with the bandgap anisotropy, within the energy range of the Stocks shift between emission and absorption spect ra of the dye. The bands of amplified spontaneous emission, which show the same anisotropy as the bandgap, have been observed. Besides, the isotropic amplified spontaneous emission band has been detected at the high intensity excitation, which band was tentatively understood as the result of the wea k localization of photons in the gain medium with embedded scatterers.