Abstract-Polarization-dependent electromagnetic responses of ultrathin and highly flexible asymmetric terahertz metasurfaces

Joshua A. Burrow, Riad Yahiaoui, Andrew Sarangan, Imad Agha, Jay Mathews, and Thomas A. Searles

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-26-32540

We report the polarization-dependent electromagnetic response from a series of novel terahertz (THz) metasurfaces where asymmetry is introduced through the displacement of two adjacent metallic arms separated by a distance δ. For all polarization states, the symmetric metasurface exhibits a low quality (Q) factor fundamental dipole mode. By breaking the symmetry, we experimentally observe a secondary dipole-like mode with a Q factor nearly 9× higher than the fundamental resonance. As δ increases, the fundamental dipole mode f1redshifts and the secondary mode f2 blueshifts creating a highly transmissive spectral window. Polarization-dependent measurements reveal a full suppression of f2 for all asymmetries at θ ≥ 60°. Furthermore, at δ ≥ 60 μm, we observe a polarization selective electromagnetic induced transparency (EIT) for the fundamental mode. This work paves the way for applications in filtering, sensing and slow-light devices common to other high Q factor THz metasurfaces with EIT-like response.

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