June 14, 2018
K-State plasmonic light enhancement research featured on cover of leading physics journal
Kansas State University physics research on plasmonic light enhancement is featured on the cover of the June 1 issue of Physical Review Letters, which is among the highest-impact physics journals.
A research team at the physics department and affiliated J.R. Macdonald Laboratory for atomic, molecular and optical physics at K-State is investigating nanoplasmonic field-enhancement effects in metal nanoparticles through detailed atomistic numerical simulations.
Graduate students Jason Li and Erfan Saydanzad, who work in the research group of Uwe Thumm, professor of physics, have recently developed a scheme that allows the reconstruction of induced nanoplasmonic light fields near the surface of nanospheres. These fields are generated due to the response of nanoparticles to an external light source, here an intense pulse of infrared laser light. Near the nanoparticle's surface the induced light field intensity can exceed the intensity of the external — inducing — light by orders of magnitude. Since these response fields cannot be directly measured, theoretical modeling is essential and proceeds by deducing the induced plasmonic electric field distribution on the nanoparticles' surface from the measurable distribution of photoelectrons. These electrons are emitted from the nanoparticle by a second light pulse with a much higher frequency — and thus much higher photon energies. While leaving the nanoparticle, the photo-emitted electrons probe the plasmonic field distribution and imprint it on the surface of a photoelectron detector. The careful detection of the emitted photoelectrons therefore allows, supported by theoretical modeling, the reconstruction of transient plasmonic fields. Nanoplasmonic field enhancement is the basic physical effect in novel plasmonic devices that promise to improve the efficiency of solar cells and photo catalysis and to enable ultrafast electro-optical — light-wave — computers.
The research was carried out with support from the Department of Energy, the National Science Foundation and the Air Force Office of Scientific Research. View the cover, which is a schematic diagram of an attosecond nanoplasmonic imaging setup with spatiotemporal resolution, and read the Physical Review Letters article.