Experimental confirmation of miniature spiral plasmonic lens as a circular polarization analyzer.
A spiral plasmonic lens can focus circular polarization of a given handedness while simultaneously defocus the circular polarization of the opposite chirality, which may be used as a miniature circular polarization analyzer. In this letter, we experimentally investigated the plasmonic focusing properties of the spiral lens using a collection mode near-field scanning optical microscope. A single Archimedes' spiral slot with a single turn was etched through gold thin film as a spiral plasmonic lens. The plasmonic field at the focus of a spiral lens strongly depends on the spin of the incident photon. Circular polarization extinction ratio better than 50 is obtainable with a device size as small as only 4 times of surface plasmon wavelength.
Chen
Weibin
W
Electro-Optics Graduate Program, University of Dayton, 300 College Park, Dayton, Ohio 45469, USA.
Abeysinghe
Don C
DC
Nelson
Robert L
RL
Zhan
Qiwen
Q