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.