Publications

Characterization of an active metasurface using terahertz ellipsometry

Karl, Nicholas; Heimbeck, Martin S.; Everitt, Henry O.; Chen, Hou T.; Taylor, Antoinette J.; Brener, Igal B.; Benz, Alexander; Reno, J.L.; Mendis, Rajind; Mittleman, Daniel M.

Switchable metasurfaces fabricated on a doped epi-layer have become an important platform for developing techniques to control terahertz (THz) radiation, as a DC bias can modulate the transmission characteristics of the metasurface. To model and understand this performance in new device configurations accurately, a quantitative understanding of the bias-dependent surface characteristics is required. We perform THz variable angle spectroscopic ellipsometry on a switchable metasurface as a function of DC bias. By comparing these data with numerical simulations, we extract a model for the response of the metasurface at any bias value. Using this model, we predict a giant bias-induced phase modulation in a guided wave configuration. These predictions are in qualitative agreement with our measurements, offering a route to efficient modulation of THz signals.