A team of U.S. and Canadian scientists has created an easily fabricated sputtered-on flat thin-film metamaterial lens that works at UV wavelengths. The team includes scientists from the National Institute of Standards and Technology (NIST; Gaithersburg, MD), the University of Maryland (College Park, MD), Syracuse University (Syracuse, NY), and the University of British Columbia (Kelowna, BC, Canada). The lens consists of alternating layers of metal and dielectric--in this case, silver (Ag) and titanium dioxide (TiO_2) on the order of 30 nm thick--on a transparent glass substrate. The structure forms many strongly coupled plasmonic sheet waveguides that allow a transverse-magnetic-polarized (TMP) backwards electromagnetic mode with a frequency that falls between the bulk plasmon-resonance frequency of the metal and the surface plasmon-resonance frequency of the metal-dielectric interface; in this case, the researchers chose to work with light at 363.8 nm.
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