作者
Denis Garoli, Pierfrancesco Zilio, Yuri Gorodetski, Francesco Tantussi, Francesco De Angelis
发表日期
2016/9/12
期刊
Nano letters
卷号
16
期号
10
页码范围
6636-6643
出版商
American Chemical Society
简介
We demonstrate the generation of far-field propagating optical beams with a desired orbital angular momentum by using a smooth optical-mode transformation between a plasmonic vortex and free-space Laguerre–Gaussian modes. This is obtained by means of an adiabatically tapered gold tip surrounded by a spiral slit. The proposed physical model, backed up by the numerical study, brings about an optimized structure that is fabricated by using a highly reproducible secondary electron lithography technique. Optical measurements of the structure excellently agree with the theoretically predicted far-field distributions. This architecture provides a unique platform for a localized excitation of plasmonic vortices followed by its beaming.
学术搜索中的文章
D Garoli, P Zilio, Y Gorodetski, F Tantussi, F De Angelis - Nano letters, 2016