Department of Chemistry, Northwestern University, Evanston, IL 60208.
Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208.
Proc Natl Acad Sci U S A. 2020 Sep 22;117(38):23380-23384. doi: 10.1073/pnas.2008818117. Epub 2020 Sep 8.
This paper reports how the spectral linewidths of plasmon resonances can be narrowed down to a few nanometers by optimizing the morphology, surface roughness, and crystallinity of metal nanoparticles (NPs) in two-dimensional (2D) lattices. We developed thermal annealing procedures to achieve ultranarrow surface lattice resonances (SLRs) with full-width at half-maxima linewidths as narrow as 4 nm from arrays of Au, Ag, Al, and Cu NPs. Besides annealing, we developed a chemical vapor deposition process to use Cu NPs as catalytic substrates for graphene growth. Graphene-encapsulated Cu NPs showed the narrowest SLR linewidths (2 nm) and were stable for months. These ultranarrow SLR nanocavity modes supported even narrower lasing emission spectra and high nonlinearity in the input-output light-light curves.
本文报告了如何通过优化二维（2D）晶格中金属纳米粒子（NPs）的形态、表面粗糙度和结晶度，将等离子体共振的光谱线宽缩小到几个纳米。我们开发了热退火程序，从 Au、Ag、Al 和 Cu NPs 的阵列中实现了半峰全宽线宽窄至 4nm 的超窄表面晶格共振（SLR）。除了退火，我们还开发了一种化学气相沉积工艺，使用 Cu NPs 作为石墨烯生长的催化衬底。石墨烯封装的 Cu NPs 显示出最窄的 SLR 线宽（2nm），并且可以稳定数月。这些超窄 SLR 纳米腔模式支持更窄的激光发射光谱和输入-输出光-光曲线中的高非线性。
