Refracting surface plasmon polaritons with nanoparticle arrays.
Refraction of surface plasmon polaritons (SPPs) by various structures formed by a 100-nm-period square lattice of gold nanoparticles on top of a gold film is studied by leakage radiation microscopy. SPP refraction by a triangular-shaped nanoparticle array indicates that the SPP effective refractive index increases inside the array by a factor of approximately 1.08 (for the wavelength 800 nm) with respect to the SPP index at a flat surface. Observations of SPP focusing and deflection by circularly shaped areas as well as SPP waveguiding inside rectangular arrays are consistent with the SPP index increase deduced from the SPP refraction by triangular arrays. The SPP refractive index is found to decrease slightly for longer wavelengths within the wavelength range of 700-860 nm. Modeling based on the Green's tensor formalism is in a good agreement with the experimental results, opening the possibility to design nanoparticle arrays for specific applications requiring in-plane SPP manipulation.
Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4A, DK-9220Aalborg Øst, Denmark. ilya@nano.aau.dk
Ilya P
IP
Radko
Andrey B
AB
Evlyukhin
Alexandra
A
Boltasseva
Sergey I
SI
Bozhevolnyi
D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008962:Models, Theoretical; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D012031:Refractometry / Q000295:instrumentation* / Q000379:methods; D020349:Surface Plasmon Resonance / Q000295:instrumentation* / Q000379:methods