Distribution of radiated power in photonic crystals with incomplete photonic bandgap

Summary form only given. In this paper we study the energy flow inside an inverted opaline photonic crystal for the frequencies near the Bragg stopband. We present a theoretical and experimental study of a far field intensity of the spontaneous emission of dye molecules randomly distributed and orientated inside the crystal. Due to the random orientation of molecules, such an incoherent light source leads to the emission of photons with a continuum of different wave-vectors directions. In what follows we assume that in the steady-state regime, all photonic crystal eigenstates (Bloch waves) are equally occupied. Under this assumption the field far from the source is assumed to be a corresponding Bloch eigenwave propagating in the observation direction.