Nanoscale optical field localization by resonantly focused plasmons.
We experimentally demonstrate use of plasmonic resonant phenomena combined with strong field localization to enhance efficiency of confining optical fields in a Si waveguide. Our approach utilizes a plasmonic resonant nano-focusing-antenna (RNFA), that simultaneously supports several focusing mechanisms in a single nanostructure, integrated with a lossless Si waveguide utilized with silicon-on-insulator (SOI) technology, to achieve a sub-diffraction limited focusing with a nanoscale (deeply subwavelength) spot size. The metallic RNFA effectively converts an incoming propagating waveguide mode to a localized resonant plasmon mode in an ultrasmall volume in all 3 dimensions. The near-field optical measurements of the fabricated RNFA using heterodyne near-field scanning optical microscope (H-NSOM) validate the theoretical predictions showing strong optical field localization.
Feng
Liang
L
Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093, USA. lifeng@ucsd.edu
Van Orden
Derek
D
Abashin
Maxim
M
Wang
Qian-Jin
QJ
Chen
Yan-Feng
YF
Lomakin
Vitaliy
V
Fainman
Yeshaiahu
Y