Observation of finite-size-induced emission decay rates in self-assembled photonic crystals

Abstract

We study the extent of spontaneous emission inhibition in self-assembled photonic crystals where the light path is routinely affected by unavoidable imperfections of the crystal and its finite-size. We discuss the role of finite-size effects that inadvertently modify the local density of optical states (LDOS) using time-resolved decay rate measurements from the single domains of real synthesized photonic crystals. We have obtained 34% contrast in the measured emission lifetimes at the stop gap wavelength in comparison to a wavelength outside the stop gap. We have shown a remarkable variation in the emission lifetimes at the stop gap for several domains across the sample which is nullified within a single domain. The results manifest wavelength-dependent linear scaling of lifetimes with the finite-size of the crystal domain. This is a signature of direct dependence of LDOS suppression on the crystal's finite-size which is also found to be in accordance with a recent theoretical model. The precise single-domain measurements result in a robust modification of lifetime in an otherwise weakly classified self-assembled photonic crystal.