Studies of optical transitions related to pi-conjugated polymers and laserdyes infiltrated in opal photonic crystals

We have investigated the emission propel-ties of the laser dye: DCM, and ph otoinduced absorption (PA) properties of the pi -conjugated polymer: DOO-PP P, in solutions which were infiltrated into porous synthetic opals. The inf iltrated materials were chosen such that an overlap exists between the phot oluminescence (PL) or PA spectra and the Bragg stop-band of the opal. We fo und that the PL spectrum of the dye-infiltrated opal shows angle-resolved e nergy redistribution. We observed PL enhancement at the high frequency edge of the Bragg stop-band and PL inhibition for frequencies inside the stop-b and, with the same angular dispersion as that of the Bragg stop-band. A mod el is discussed to explain these PL changes, where the dielectric constant modulation affects the angular distribution of the dye dipole emission. Sim ilar changes were observed in the PA spectrum of the infiltrated polymer so lution, where the dielectric constant modulation affects the absorption dip ole moment of long-lived photo-excitations on the polymer chains, such as t ripler excitons. (C) 2001 Elsevier Science B.V. All rights reserved.