Five-Fold Reduction of Lasing Threshold near the First $ΓL$-Pseudogap of ZnO Inverse Opals

Abstract

We report room temperature lasing in ZnO inverse opal photonic crystals in the near-ultraviolet (UV) frequency. We observe random lasing due to disorder in the structures when the photonic pseudogaps are located away from the ZnO gain spectrum. Tuning the first $ΓL$-pseudogap to the gain peak leads to a five-fold reduction in lasing threshold and frequency shift of lasing modes due to the enhanced confinement of light.

10 pages, 6 figures