Hyperbolic metamaterials (HMMs) are artificially engineered optical media that have been used for light confinement, excited-state decay-rate engineering, and subwavelength imaging, due to their highly anisotropic permittivity and with it the capability of supporting high-k modes. HMMs in the infrared range can be conceived for additional applications such as free space communication, thermal engineering, and molecular sensing. Here, we demonstrate infrared HMMs comprised of periodic indium-tin-oxide nanorod arrays (ITO-NRAs). We show that the ITO-NRA-based HMMs exhibit a stationary epsilon-near-pole resonance in the near-infrared regime that is insensitive to the filling ratio, and a highly tunable epsilon-near-zero resonance in the mid-infrared range depending on the array periodicity. Experimental results are supported by finite-element simulations, in which the ITO-NRAs are treated both explicitly and as an effective hyperbolic media. Our work presents a low-loss HMM platform with favorable spectral tunability in the infrared range.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)