Kim Gunpyo, Song Seok Ho, Yoon Jae Woong
Department of Physics, Hanyang University, Seoul, 04763, Korea.
Sci Rep. 2022 Jul 5;12(1):11333. doi: 10.1038/s41598-022-15319-y.
Creating micro and nano lasers, high threshold gain is an inherent problem that have critically restricted their great technological potentials. Here, we propose an inverse-cavity laser structure where its threshold gain in the shortest-cavity regime is order-of-magnitude lower than the conventional cavity configurations. In the proposed structure, a resonant feedback mechanism efficiently transfers external optical gain to the cavity mode at a higher rate for a shorter cavity, hence resulting in the threshold gain reducing with decreasing cavity length in stark contrast to the conventional cavity structures. We provide a fundamental theory and rigorous numerical analyses confirming the feasibility of the proposed structure. Remarkably, the threshold gain reduces down by a factor ~ 10 for a vertical-cavity surface-emitting laser structure and ~ 0.17 for a lattice-plasmonic nanocavity structure. Therefore, the proposed approach may produce extremely efficient miniature lasers desirable for variety of applications potentially beyond the present limitations.
制造微型和纳米激光器时，高阈值增益是一个固有问题，严重限制了它们巨大的技术潜力。在此，我们提出一种反腔激光器结构，其在最短腔 regime 中的阈值增益比传统腔配置低一个数量级。在所提出的结构中，一种共振反馈机制能以更高的速率将外部光学增益高效地转移到较短腔的腔模上，因此导致阈值增益随腔长减小而降低，这与传统腔结构形成鲜明对比。我们提供了一个基本理论和严格的数值分析，证实了所提出结构的可行性。值得注意的是，对于垂直腔面发射激光器结构，阈值增益降低了约 10 倍，对于晶格等离子体纳米腔结构降低了约 0.17 倍。因此，所提出的方法可能会产生各种应用所需的极其高效的微型激光器，潜在地突破当前的限制。
