Plasmonic Halos—Optical Surface Plasmon Drumhead Modes: Boston College researchers' unique nanostructure produces novel 'plasmonic halos' Nanoscopic microcavities offer newfound control in light filtering.
CHESTNUT HILL, MA (February 7, 2013) – Using the geometric and material properties of a unique nanostructure, Boston College researchers have uncovered a novel photonic effect where surface plasmons interact with light to form "plasmonic halos" of selectable output color. The findings appear in the journal Nano Letters.
The novel nanostructure proved capable of manipulating electron waves known as surface plasmon polaritons, or SPPs, which were discovered in the 1950s but of late have garnered the attention of scientists for their potential applications in fields that include waveguiding, lasing, color filtering and printing.
The team put a layer of a polymer film on a glass substrate and then dotted the surface with holes precisely defined by a process of electron beam lithography, using the BC Integrated Sciences Nanofabrication Clean Room facility. The team next applied a layer of silver, thick enough to be nontransparent to visible light. In addition to covering the thin film on top, the silver coated the contours of the holes in the film, as well as the exposed circles of the glass substrate below. The effect produced an array of silver microcavities.
By adjusting the type of metal used to coat the structure or varying the circumferences of the microcavities, Naughton said the step-gap structure is capable of manipulating the optical properties of the device in the visible light range, giving the researchers newfound control in light filtering.
This kind of control, the team reports, could have applications in areas such as biomedical plasmonics or discrete optical filtering.
Contact: Ed Hayward firstname.lastname@example.org 617-552-4826 Boston College