Surface plasmon polariton propagation around bends:
Surface plasmon polaritons (SPPs) on a flat surface may be confined to dimensions much smaller than the wavelength of light, and it might be possible to realize compact plasmon-based optoelectronic circuits. To study the feasibility of such devices, it is necessary to quantify the efficiency of SPP propagating around bends and understand the nature of SPPs on curved interfaces. Using both analytical and numerical techniques, I calculate the propagation efficiency as a function of the radius of curvature and investigate how the field confinement affects the curvature-induced radiation of SPPs propagating around bends. [References: "Surface plasmon polariton propagation around bends at a metal-dielectric interface," K. Hasegawa, J. U. Nöckel and M. Deutsch, Appl. Phys. Lett. 84, 1835 (2004). "Curvature-induced radiation from surface plasmon polaritons propagating around bends," K. Hasegawa, J. U. Nöckel and M. Deutsch, manuscript in preparation.]

Coherently driven localized surface plasmons on percolative nanoshells:
The tunability and the enhancement of elastic and inelastic light scattering from nanoscale dielectric spheres coated with smooth and continuous metallic shell have been studied extensively in the last several years. Nanospheres with percolative shells may provide additional tunability and enhancement since percolative metal films support electromagnetic field "hotspots", or localized surface plasmons. In order to understand the linear plasmonic response of such nanoshells, C. Rhode and I have developed the modified scaling theory, which suggests that the localized surface plasmons oscillate coherently owning to the spherical resonator geometry of the system. [Reference: “Coherent light scattering from semicontinuous silver nanoshells near the percolation threshold,” C. A. Rohde, K. Hasegawa and M. Deustch, Phys. Rev. Lett. 96, 045503 (2006).]

Optical properties of metal-dielectric-metal spherical resonators:
Layered metal-dielectric particles support surface plasmon resonances whose frequencies are tunable with particles’ geometric parameters. A metal-dielectric-metal microsphere (MDM) consists of metallic core comparable in size to optical wavelengths, surrounded by one sequence of a dielectric shell followed by a dielectric shell followed by a metallic shell. Using the modified Mie theory, C. Rohde and I have found that it is possible to design an MDM such that it supports a band of resonances that are nearly identical. These numerous modes may be excited simultaneously by an incident plane-wave, resulting in a several-fold enhancement in its absorption cross-section compared to that of a solid metal sphere. The enhanced absorption peak can be tuned over the entire visible range. Our calculations suggest that MDMs may also be used to enhance nonlinear phenomena. Additionally, we find a window around the flat dispersion frequency where the MDM sphere has less out of beam scattering than a solid metal sphere of the same size. This forward transparency peak is also tunable in depth, width and central maximum. [References: “Enhanced surface plasmon resonance absorption in metal-dielectric-metal layered microspheres,” K. Hasegawa, C. A. Rohde and M. Deustch, Opt. Lett. 31, 1136 (2006). "Plasmon assisted transparency in layered microspheres," C. A. Rohde, K. Hasegawa and M. Deustch, manuscript in preparation.]