Single-Crystal Organic Heterostructure for Single-Mode Unidirectional Whispering-Gallery-Mode Laser

摘要

Organic single crystals have attracted great attention for solid-state lasers owing to their smooth morphologies with inherent optical microcavity, ordered molecular packing mode with minimized defects density, and high photoluminescence quantum efficiency. However, the organic single-crystal lasers, including whispering-gallery-mode (WGM) lasers with nondirectional emission and Fabry-Perot (F-P) lasers with inherent high-lasing threshold, cannot achieve state-of-the-art performance. Herein, the hierarchical self-assembly of organic single-crystal heterostructures made from cube-shaped microdisks with optical gain and microwires with optical waveguide characteristics is demonstrated, which realize the unidirectional WGM laser action with a low-lasing threshold of approximate to 600 nJ cm(-2). The lattice mismatch rate principle contributes to the growth of these single-crystal organic heterostructures. More significantly, the waveguide-coupled WGM microcavity with a coupling coefficient of 28.8% proves that the unidirectional outcoupling of the single-crystal WGM lasers from the single-crystal wire waveguides is achieved. The results will pave an alternative avenue for high-performance organic single-crystal lasers.