Electrically-driven spectrally-broadened random lasing based on disordered photonic crystal structures

摘要

We present the effect of radius randomness on the resonant spectrum and modal characteristics of a photonic crystal. With the introduction of randomness, different localizations were analyzed. The random pattern was then fabricated onto our lateral cavity surface emitting laser. Electrically driven random lasing was obtained with the localization and broadened spectrum, and the decrease of threshold and the increase of output power were also observed. The decreased threshold was due to the appearance of additional modes and the degree of localization. The output power reached a maximum with a random variance of 20 nm. It meant that there was a transition case in a regime ranging from Anderson localization to the local band edge resonance, and a balance between the Fabry-Perot-like effect and the random modulation effect. When the random variance reached 50 nm, the transition case in a regime ranging from localized to diffusive became remarkable. The experimental results are consistent with our theoretical analysis. One of the properties that make a random laser special with respect to regular lasers is its complex features in emission spectra, which means low spectral coherence. Our investigation on this kind of laser has referential and instructional significances for full-field imaging at visible wavelengths and other wavelengths.