NSF Nanoscale Science and Engineering Centre, 3112 Etcheverry Hall, University of California, Berkeley, California 94720, USA.
Nat Mater. 2011 Feb;10(2):110-3. doi: 10.1038/nmat2919. Epub 2010 Dec 19.
Plasmon lasers are a new class of coherent optical amplifiers that generate and sustain light well below its diffraction limit. Their intense, coherent and confined optical fields can enhance significantly light-matter interactions and bring fundamentally new capabilities to bio-sensing, data storage, photolithography and optical communications. However, metallic plasmon laser cavities generally exhibit both high metal and radiation losses, limiting the operation of plasmon lasers to cryogenic temperatures, where sufficient gain can be attained. Here, we present a room-temperature semiconductor sub-diffraction-limited laser by adopting total internal reflection of surface plasmons to mitigate the radiation loss, while using hybrid semiconductor-insulator-metal nanosquares for strong confinement with low metal loss. High cavity quality factors, approaching 100, along with strong λ/20 mode confinement, lead to enhancements of spontaneous emission rate by up to 18-fold. By controlling the structural geometry we reduce the number of cavity modes to achieve single-mode lasing.
等离子体激光是一类新的相干光放大器，能够在低于其衍射极限的条件下产生和维持光。它们强、相干且受限的光场可以显著增强光物质相互作用，并为生物传感、数据存储、光刻和光通信带来全新的功能。然而，金属等离子体激光腔通常具有较高的金属和辐射损耗，这限制了等离子体激光在低温下的运行，因为只有在低温下才能获得足够的增益。在这里，我们通过采用表面等离激元的全内反射来减轻辐射损耗，同时使用混合半导体-绝缘体-金属纳米正方形来实现强限制和低金属损耗，从而实现了室温下亚衍射极限的半导体激光。高的腔品质因数，接近 100，以及强的 λ/20 模式限制，导致自发发射率提高了 18 倍。通过控制结构几何形状，我们减少了腔模式的数量，实现了单模激射。
