Ultrawide thermal free-carrier tuning of dielectric antennas coupled to epsilon-near-zero substrates.

ABSTRACT: The principal challenge for achieving reconfigurable optical antennas and metasurfaces is the need to generate continuous and large tunability of subwavelength, low-Q resonators. We demonstrate continuous and steady-state refractive index tuning at mid-infrared wavelengths using temperature-dependent control over the low-loss plasma frequency in III-V semiconductors. In doped InSb we demonstrate nearly two-fold increase in the electron effective mass leading to a positive refractive index shift (Δn > 1.5) that is an order of magnitude greater than conventional thermo-optic effects. In undoped films we demonstrate more than 10-fold change in the thermal free-carrier concentration producing a near-unity negative refractive index shift. Exploiting both effects within a single resonator system

SUBMITTER: Iyer PP 

PROVIDER: S-EPMC5589832 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature