Enhancement of molecular interactions in strongly scattering dielectric composite optical media

We observed fast nonexponential luminescence decay from a molecular dye in a suspension of dyed polystyrene spheres when both the interparticle distance and the sphere size is comparable to the wavelength of the emission. This nonexponential lifetime depends on the square root of the time, suggesting a resonance dipole-dipole interaction associated with the Mie resonances. This phenomenon is interpreted in terms of resonance energy transfer between molecules leading to the formation of a photonic band mode.