Center for Optical Technologies, Electrical and Computer Engineering Department, Lehigh University, Bethlehem, PA 18015, USA.
Proc Natl Acad Sci U S A. 2011 Mar 29;108(13):5169-73. doi: 10.1073/pnas.1014963108. Epub 2011 Mar 14.
We report the experimental observation of a trapped rainbow in adiabatically graded metallic gratings, designed to validate theoretical predictions for this unique plasmonic structure. One-dimensional graded nanogratings were fabricated and their surface dispersion properties tailored by varying the grating groove depth, whose dimensions were confirmed by atomic force microscopy. Tunable plasmonic bandgaps were observed experimentally, and direct optical measurements on graded grating structures show that light of different wavelengths in the 500-700-nm region is "trapped" at different positions along the grating, consistent with computer simulations, thus verifying the "rainbow" trapping effect.
我们报告了在绝热渐变金属光栅中捕获彩虹的实验观察结果，该实验旨在验证这种独特的等离子体结构的理论预测。我们制造了一维渐变纳米光栅，并通过改变光栅槽深来调整其表面色散特性，光栅的尺寸通过原子力显微镜得到了确认。我们实验观察到了可调谐的等离子体带隙，并对渐变光栅结构进行了直接的光学测量，结果表明，在 500-700nm 波段的不同波长的光在光栅上的不同位置被“捕获”，这与计算机模拟结果一致，从而验证了“彩虹”捕获效应。
