One of the goals of OMEL is to investigate how patterned metallic surfaces interact with light. Special electromagnetic waves known as surface plasmons can exist on a metal interface. Because these waves combine both light and oscillating surface charges, they can lead to interesting new optical behaviors. Consequently, the field of plasmonics has arisen to study how man-made metallic nanostructures can control the generation, propagation, and manipulation of surface plasmons. Such investigations are in part motivated by the fact that surface plasmons can concentrate light into extremely small nanoscale volumes — an effect that is potentially useful for a range of applications, including solar cells, photochemical cells, and sensors.
However, to really exploit this effect, one needs precisely patterned metallic films that include structures such as sharp metal tips, ridges, grooves, apertures, etc. Within OMEL we work to develop simple fabrication procedures to create such structures. The resulting films are then investigated either for new physical phenomena or for device applications. One of our favorite strategies is to utilize "template stripping," in which a metal film is deposited onto a pre-patterned silicon wafer and then peeled off. Although extremely simple, this approach can create a large variety of interesting high-quality plasmonic devices.
For our early work on template stripping, see: "Ultrasmooth Patterned Metals for Plasmonics and Metamaterials”, P. Nagpal, N. C. Lindquist, S.-H. Oh, and D. J. Norris, Science 325, 594 (2009).