Grating couplers for broadside input and output coupling of long-range surface plasmons.
Metal gratings for in-coupling a Gaussian beam incident from broadside to the long-range surface plasmon polariton (LRSPP) propagating in one direction along a membrane-supported Au slab bounded by air or water are proposed and modeled by the finite-difference time-domain method. Grating couplers for out-coupling the propagating LRSPP into free radiation directed along broadside are also investigated. Short grating designs consisting of a small number of Au bumps yield 15% to 20% in-coupling efficiencies, and about 60% out-coupling efficiencies. LRSPP back-reflections along the membrane waveguide caused by the out-coupling grating are also calculated and discussed.
Chen
Chengkun
C
School of Information Technology and Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa K1N 6N5 Ontario, Canada. chengkun@site.uottawa.ca <chengkun@site.uottawa.ca>
Berini
Pierre
P