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Boston College Professor of Physics Krzysztof Kempa’s report “Controlling light propagation with nanowires,” co-authored with researcher Yun Peng, has been selected as one of the most notable papers of 2012 by the journal Applied Physics Letters.
The research centered on using charge oscillations of electrons, caused by an interaction of incident light with metal – in Kempa’s case a silver wire – to effectively transport light from one end of the wire to another with a negligible loss of energy, according to Kempa, who co-authored the paper with then-doctoral student Peng, who is now a lab manager in the Physics Department.
Using calculations and computer simulations, Kempa said the research team demonstrated that when electrons are excited with polarized electromagnetic waves at one end, a nanowire can function as an efficient waveguide for the electron oscillations, known as surface plasmon polaritons, or SPPs.
The findings mark an important step toward proof of principle for a new class of microscope under development by a team of BC scientists, including Kempa, funded by the W.M. Keck Foundation. The team is developing a prototype nanoscale coaxial optical microscope that uses light-guiding metamaterials to create images that reveal micro- and macroscopic matter with significantly improved clarity. The design will allow the microscope to focus beams of light on sub-wavelength-sized matter, such as cells or proteins, and then return that light to a camera that presents the image.
Kempa attributed the interest in the paper, published on April 23, 2012, to its fresh perspective on a fundamental topic – the free movement of electrons and their excitations within metals. The research showed that the well-established research into plasmons could offer significant insights and experimental value in the realm of nanotechnology.
As a result of the report, other scientists are taking a renewed look at the subject, said Kempa. “People could see that it is possible to transport light along a wire with negligible loss, as long as good coupling of light into and from the wire is assured. In addition, we have demonstrated that the waveguided light is well confined to the wire, which is important for the nano-microscope application,” said Kempa.
Kempa’s colleagues at BC are presently testing the concept experimentally.
The Applied Physics Letters article can be found at: http://apl.aip.org/resource/1/applab/v100/i17/p171903_s1