Abstract-Broadband THz radiation through tapered semiconductor gratings on high-index substrate

Truong Khang Nguyen, Phuc Toan Dang, Ikmo Park, and Khai Quang Le

https://www.osapublishing.org/josab/abstract.cfm?uri=josab-34-3-583&origin=searchtapere

We numerically demonstrate an extraordinary optical transmission (EOT) through semiconductor gratings with plasmonic properties on a high-index substrate over a broad terahertz (THz) bandwidth at the plasmonic Brewster channel. The THz EOT is due to impedance matching, an inherently non-resonant mechanism, at the grating entrance and exit faces, which are periodically carved with tapered slits. The optimal grating geometry provides a transmission of over 85% over a broad 0.2–1.0 THz bandwidth at a Brewster angle of incidence of 75°. In addition, we introduce a perfect THz absorber with low-loss and metal-free properties over a broad operating bandwidth based on the plasmonic Brewster transmission concept.

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