The ability to manipulate light at subwavelength scales is critical for plasmonic applications, such as superlenses, and optical cloaking devices. Such optical properties have been demonstrated using patterned surfaces and resonance-based metamaterials. With the advent of more sophisticated fabrication techniques that facilitate user-control over the shapes and compositions of nanoparticles, complex plasmonic nanostructures that are asymmetrically shaped and/or composed of multiple materials have been utilized to manipulate light. Specifically, three dimensional (3D) nanocups—nanoparticles that consist of an asymmetric gold cap with a dielectric core—exhibit an optical response that is highly tunable in the visible and infrared regions. Furthermore, because the opening of the conductive cap is interrupted by a dielectric material, nanocups facilitate a magnetic plasmon response with magnetoinductive coupling between the cup and the incident radiation. This property enables nanocups to redirect light in the direction of the transverse axis of the cup, regardless of the incidence angle. In this study, we used advanced nanofabrication techniques to precisely control the size and the pitch of the nanocups, thus tuning the optical response to the desirable visible range.
Lo, J., Hong, S., Andersen, R., Lee, L., Horsley, J., Skinner, J., “Fabrication of a Large, Ordered, Three-Dimentional Nanocup Array”, Appl. Phys. Lett. 101, 081109 (2012)
(Oral Presentation) Lo, J., Andersen, R., Horsley, J., Skinner, J., “Fabrication of Large Arrays of Ordered 3D Nanocups for Plamonic Applications”, International Conference on Electron, Ion, Photon Beam Technology and Nanofabrication (EIPBN 2010), Alaska, United States