Plasmonic resonance shift for various nanodevice geometries

Plasmonic nanodevices are metallic structures that exhibit plasmonic effects when exposed to light, causing scattering and enhancement of that light. These plasmons makes it possible for light to be focused below the diffraction limit. Darkfield spectroscopy has been used to capture the scattering spectra of these structures in order to examine the scattering and resonant frequencies of the plasmons provided by the devices. The geometries of the devices change which wavelengths of light are most readily able to couple to the device, resulting in a change in the wavelength of the scattered light. A variety of device geometries and configurations will be studied, including nanodiscs, nanowires, and plasmonic gratings, along with double-width nanogap plasmonic gratings. These new structures will have features below the fabrication limit of electron-beam lithography, i.e. sub-10 nanometer features. The polarization dependencies of these resonance modes are investigated as well. A relation between device geometry and wavelength will be drawn; in effect, this will allow the selection of geometry of the fabricated device based on the desired wavelength of light to be scattered. Preliminary Raman spectroscopy will also be performed in order to study the device response and usefulness for surface-enhanced Raman spectroscopy.