Surface plasmon resonator: Design, construction, and observation in the farfield

We have studied the behavior of surface plasmons (SPs) in valley like structures [Schroter et al., Ultramicroscopy 68, 223 (1997)] and found that SPs traveling in both directions in such a cavity yield interference patterns in the farfield, which can be measured as specular and retroreflection. We have studied and designed the structures using finite element method in addition to a heuristic model, fabricated the devices using photolithography and experimentally verified the operation of the resonators, by observing the interference patterns of the specular and retroreflection in the farfield. We have found that the experimental results agree with the simulations, and explained the discrepancies. These structures can be useful in the study of the propagation length of SPs via observation in the farfield of the specular and the retroreflected light in laser industry and could be miniaturized to yield small biosensors. (C) 2010 American Institute of Physics. [doi:10.1063/1.3487940]