Controlled Outcoupling of Whispering-Gallery-Mode Lasers Based on Self-Assembled Organic Single-Crystalline Microrings.

Lv, Yuanchao; Xiong, Xiao; Liu, Yingying; Yao, Jiannian; Li, Yong Jun; Zhao, Yong Sheng · Nano Lett · 2019

basic_science · Level V

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Abstract

The outcoupling of whispering-gallery-mode (WGM) lasers is crucial for the realization of various photonic functionalities, yet present material structures still suffered the unexpected surface damages or contaminations in the multistep micro/nanofabrications. Here, we propose a strategy to achieve controlled outcoupling of WGM lasers in self-assembled organic single-crystalline microrings. The microrings with molecular-smooth surfaces functioned as organic crystalline whispering-gallery-mode microlasers with a lasing threshold of ∼14.2 μJ cm<sup>-2</sup> and a quality factor on the order of 10<sup>3</sup> to 10<sup>4</sup>. The circular self-assembly allowed us to design different derived ring-based structures toward desired outcoupling of the WGM lasers, including unidirectional laser output from wire-ring coupled structures, and single-mode lasing in double-ring coupled systems. The results would provide an alternative avenue to construct versatile organic nanoscale lasers and related components with specific photonic applications.