Electro-Optics Program, University of Dayton, 300 College Park, Dayton, Ohio 45469, USA.
Opt Lett. 2010 Jun 1;35(11):1755-7. doi: 10.1364/OL.35.001755.
The spiral plasmonic lens is capable of focusing the left-hand and right-hand circular polarizations into spatially separated plasmonic fields caused by the geometric phase effect. Its function as a circular polarization analyzer has been studied analytically and numerically in a previous Letter [Opt. Lett.34, 3047 (2009)OPLEDP0146-959210.1364/OL.34.003047]. Single Archimedes' spiral grooves with lateral sizes of approximately 4lambda(spp) (approximately 2.8 microm) were milled into a gold thin film by using a focused ion beam. The function of such a simple spiral plasmonic lens serving as a circular polarization analyzer was experimentally characterized with two-photon fluorescence microscopy. The circular polarization extinction ratio of the two-photon fluorescent signal is estimated to be larger than 200 for a detector diameter up to 0.3lambda(spp).
螺旋等离子透镜能够将左旋和右旋圆偏振光聚焦到由几何相位效应引起的空间分离的等离子体场中。它作为圆偏振光分析器的功能在前一封信件[Opt. Lett.34, 3047 (2009)OPLEDP0146-959210.1364/OL.34.003047]中进行了分析和数值研究。通过使用聚焦离子束，在金薄膜中刻蚀出具有大约 4lambda(spp)（约 2.8 微米）横向尺寸的单个阿基米德螺旋槽。利用双光子荧光显微镜实验表征了这种作为圆偏振光分析器的简单螺旋等离子透镜的功能。对于探测器直径高达 0.3lambda(spp)，双光子荧光信号的圆偏振消光比估计大于 200。
