Optical response of dipole antennas on an epsilon-near-zero substrate

Materials with vanishing permittivity (epsilon-near-zero or ENZ materials) show unconventional optical behavior. Here we show that plasmonic dipole antennas on an ultrathin ENZ substrate have properties significantly different from antennas on a traditional substrate. Specifically, the presence of a 23-nm-thick ENZ material strongly modifies the linear response of plasmonic antennas and, as a result, the resonant wavelength is independent of the linear dimensions of the dipole antenna.