Chen Zhigang, Li Xu, Taflove Allen, Backman Vadim
Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois 60208, USA.
Appl Opt. 2006 Feb 1;45(4):633-8. doi: 10.1364/ao.45.000633.
We report what we believe to be a novel backscattering phenomenon associated with localized optical intensity peaks (spanning as little as 43 nm) arising at the shadow-side surfaces of plane-wave-illuminated dielectric microcylinders of noncircular cross sections. Namely, for nanometer-scale dielectric particles positioned within the localized intensity peaks, their backscattering of visible light is enhanced by several orders of magnitude relative to the case of isolated nanoparticles (i.e., Rayleigh scattering). The positions of the localized intensity peaks can be quickly scanned along the microcylinder surface by changing either the incident wavelength or angle. This combination of giant backscattering enhancement of nanoparticles and ease and rapidity of scanning may present advantages relative to the use of fragile, mechanically scanned, near-field probes. Potential applications include visible-light detection, characterization, and manipulation of nanoparticles.
我们报告了一种我们认为是新颖的背散射现象，该现象与非圆形横截面的平面波照射介电微圆柱阴影侧表面出现的局部光强峰值（跨度小至43纳米）相关。也就是说，对于位于局部强度峰值内的纳米级介电粒子，相对于孤立纳米粒子的情况（即瑞利散射），它们对可见光的背散射增强了几个数量级。通过改变入射波长或角度，可以快速扫描微圆柱表面上局部强度峰值的位置。纳米粒子的巨大背散射增强与扫描的简便性和快速性相结合，相对于使用易碎的、机械扫描的近场探头可能具有优势。潜在应用包括纳米粒子的可见光检测、表征和操纵。
