Feng Simin, Halterman Klaus, Overfelt Pamela L, Bowling Donald
Research and Intelligence Department, Physics Division Naval Air Warfare Center, China Lake, CA 93555, USA.
Opt Express. 2009 Oct 26;17(22):19823-41. doi: 10.1364/OE.17.019823.
We investigate electromagnetic scattering from nanoscale wires and reveal the emergence of a family of exotic resonances for source waves close to grazing incidence. These grazing resonances have a much higher Q-bandwidth product and thus, a much higher Q factor and broader bandwidth than the pure plasmonic resonances found in metal nanowires. Furthermore, these grazing resonances are much less susceptible to material losses than surface plasmon resonances. Contrary to the process of exciting surface plasmon resonances, these grazing resonances can arise in both dielectric and metallic nanowires and appear near to the cutoff wavelength of the circular waveguide. This peculiar resonance effect originates from the excitation of long range guided surface waves through the interplay of coherently scattered continuum modes coupled with first-order azimuthal propagating modes of the cylindrical nanowire. These first-order cyclic Sommerfeld waves and associated cyclic Sommerfeld resonances revealed here opens up the possibility of an alternative scheme of enhanced fields with a better merit (higher Q-bandwidth product and lower loss) than conventional surface plasmon resonances in the nano-regime. This nanowire resonance phenomenon can be utilized in broad scientific areas, including: metamaterial designs, nanophotonic integration, nanoantennas, and nanosensors.
我们研究了纳米级导线的电磁散射，并揭示了对于接近掠射入射的源波，一族奇异共振的出现。这些掠射共振具有更高的Q带宽积，因此与金属纳米线中发现的纯等离子体共振相比，具有更高的Q因子和更宽的带宽。此外，这些掠射共振比表面等离子体共振更不易受材料损耗的影响。与激发表面等离子体共振的过程相反，这些掠射共振可以在介电和金属纳米线中出现，并出现在圆形波导的截止波长附近。这种奇特的共振效应源于通过相干散射连续模式与圆柱形纳米线的一阶方位传播模式的相互作用激发长程导波表面波。这里揭示的这些一阶循环索末菲波和相关的循环索末菲共振，为纳米区域中比传统表面等离子体共振具有更好性能（更高的Q带宽积和更低的损耗）的增强场替代方案开辟了可能性。这种纳米线共振现象可应用于广泛的科学领域，包括：超材料设计、纳米光子集成、纳米天线和纳米传感器。
