Open AccessNear-field nanofocusing through a combination of plasmonic Bragg reflector and converging lens
Author(s) -
Wentao Song,
Zheyu Fang,
Shan Huang,
Feng Lin,
Xing Zhu
Publication year - 2010
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.014762
Subject(s) - optics , plasmonic lens , lens (geology) , materials science , plasmon , focal length , distributed bragg reflector , reflector (photography) , optoelectronics , surface plasmon , physics , surface plasmon polariton , laser , light source
We report the near-field nanofocusing through a plasmonic lens containing a Bragg reflector and a converging lens, which consist of semitransparent annular grooves milled into a gold film with different periods along the radial direction. By illuminating the structure with a linearly polarized light, two tightly focal spots were detected by scanning near-field optical microscope. This plasmonic lens has considerably reduced direct light transmission, making the focal spots obvious. By raising the radius of half of every groove, one single spot was obtained. Furthermore, theoretical simulations prove that the light intensity of the focal spots can be doubled through adding the Bragg reflector surrounding the converging lens.