Yoon Jae Woong, Song Seok Ho, Magnusson Robert
Dept. of Electrical Engineering, University of Texas - Arlington, Box 19016, Arlington, TX 76019, USA.
Dept. of Physics, Hanyang University, Seoul 133-791, KOREA.
Sci Rep. 2014 Nov 20;4:7124. doi: 10.1038/srep07124.
We propose a mechanism of ultrahigh-Q metallic nanocavity resonances that involves an efficient loss-compensation scheme favorable for room-temperature operation. We theoretically show that surface plasmon-polaritons excited on the entrance and exit interfaces of a metallic nanocavity array efficiently transfer external optical gain to the cavity modes by inducing resonantly-amplified intracavity feedback. Surprisingly, the modal gain in the nanocavity with the externally amplified feedback is inversely proportional to the cavity length as opposed to conventional optical cavity amplifiers requiring longer cavities for higher optical gain. Utilizing this effect, we numerically demonstrate room-temperature nanocavity resonance Q-factor exceeding 10(4) in a 25-nm-wide silver nanoslit array. The proposed mechanism provides a highly efficient plasmonic amplification process particularly for subwavelength plasmonic cavities which are essential components in active nanoplasmonic devices.
我们提出了一种超高品质因数金属纳米腔共振机制，该机制涉及一种有利于室温运行的高效损耗补偿方案。我们从理论上表明，在金属纳米腔阵列的入口和出口界面上激发的表面等离激元极化激元通过诱导共振放大的腔内反馈，将外部光学增益有效地转移到腔模中。令人惊讶的是，具有外部放大反馈的纳米腔中的模式增益与腔长度成反比，这与传统光学腔放大器需要更长的腔来获得更高的光学增益相反。利用这一效应，我们通过数值模拟证明了在一个25纳米宽的银纳米狭缝阵列中，室温下纳米腔共振品质因数超过10^4。所提出的机制提供了一种高效的等离子体放大过程，特别是对于亚波长等离子体腔而言，亚波长等离子体腔是有源纳米等离子体器件的基本组成部分。
