Senanayake Pradeep, Hung Chung-Hong, Shapiro Joshua, Scofield Adam, Lin Andrew, Williams Benjamin S, Huffaker Diana L
Department of Electrical Engineering, University of California at Los Angeles, Los Angeles, California 90095, USA.
Opt Express. 2012 Nov 5;20(23):25489-96. doi: 10.1364/OE.20.025489.
We demonstrate 3D surface plasmon photoresponse in nanopillar arrays resulting in enhanced responsivity due to both Localized Surface Plasmon Resonances (LSPRs) and Surface Plasmon Polariton Bloch Waves (SPP-BWs). The LSPRs are excited due to a partial gold shell coating the nanopillar which acts as a 3D Nanopillar Optical Antenna (NOA) in focusing light into the nanopillar. Angular photoresponse measurements show that SPP-BWs can be spectrally coincident with LSPRs to result in a x2 enhancement in responsivity at 1180 nm. Full-wave Finite Difference Time Domain (FDTD) simulations substantiate both the spatial and spectral coupling of the SPP-BW / LSPR for enhanced absorption and the nature of the LSPR. Geometrical control of the 3D NOA and the self-aligned metal hole lattice allows the hybridization of both localized and propagating surface plasmon modes for enhanced absorption. Hybridized plasmonic modes opens up new avenues in optical antenna design in nanoscale photodetectors.
我们展示了纳米柱阵列中的三维表面等离子体光响应，由于局域表面等离子体共振（LSPR）和表面等离子体激元布洛赫波（SPP-BW），导致响应度增强。LSPR是由于纳米柱上部分涂覆金壳而被激发的，该金壳充当三维纳米柱光学天线（NOA），将光聚焦到纳米柱中。角光响应测量表明，SPP-BW在光谱上可以与LSPR重合，从而在1180nm处使响应度提高两倍。全波有限差分时域（FDTD）模拟证实了SPP-BW/LSPR在空间和光谱上的耦合，以增强吸收以及LSPR的性质。对三维NOA和自对准金属孔晶格的几何控制允许局域和传播表面等离子体模式的杂交，以增强吸收。杂交等离子体模式为纳米级光电探测器中的光学天线设计开辟了新途径。
