Kim, JongbumDutta, AveekNaik, Gururaj V.Giles, Alexander J.Bezares, Francisco J.Ellis, Chase T.Tischler, Joseph G.Mahmoud, Ahmed M.Caglayan, HumeyraGlembocki, Orest J.Kildishev, Alexander V.Caldwell, Joshua D.Boltasseva, AlexandraEngheta, Nader2020-02-052020-02-0520162334-253610.1364/OPTICA.3.000339https://hdl.handle.net/20.500.12573/136Office of Naval Research (ONR) (N00014-10-1-0942); Air Force Office of Scientific Research (AFOSR) (FA9550-14-1-0389); NRC/ASEE Postdoctoral Fellowship Naval Research Laboratory Nanoscience Institute (from ONR).Radiation patterns and the resonance wavelength of a plasmonic antenna are significantly influenced by its local environment, particularly its substrate. Here, we experimentally explore the role of dispersive substrates, such as aluminum-or gallium-doped zinc oxide in the near infrared and 4H-silicon carbide in the mid-infrared, upon Au plasmonic antennas, extending from dielectric to metal-like regimes, crossing through epsilon-near-zero (ENZ) conditions. We demonstrate that the vanishing index of refraction within this transition induces a "slowing down" of the rate of spectral shift for the antenna resonance frequency, resulting in an eventual "pinning" of the resonance near the ENZ frequency. This condition corresponds to a strong backward emission with near-constant phase. By comparing heavily doped semiconductors and undoped, polar dielectric substrates with ENZ conditions in the near- and mid-infrared, respectively, we also demonstrate the generality of the phenomenon using both surface plasmon and phonon polaritons, respectively. Furthermore, we also show that the redirected antenna radiation induces a Fano-like interference and an apparent stimulation of optic phonons within SiC. (C) 2016 Optical Society of Americaenginfo:eu-repo/semantics/openAccessSURFACE PHONON POLARITONSNANOANTENNA ARRAYSGRAPHENE PLASMONSBORON-NITRIDEMETAMATERIALSLIGHTABSORPTIONINDEXREALIZATIONWAVELENGTHSarticle10.1364/OPTICA.3.000339