Micro-fabricated Si subwavelength grating for frequency-domain THz beam steering covering the 0.3–0.5 THz frequency band

• Published in: Optics express Vol. 31; no. 17; p. 27147
• Main Authors: Chiba, Kohei, Okatani, Taiyu, Inomata, Naoki, Kanamori, Yoshiaki
• Format: Journal Article
• Language: English
• Published: 14.08.2023
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.492942

We designed and fabricated beam steering subwavelength grating (BS-SWG) with high efficiency, wide angles, and broadband beam steering in the terahertz (THz) range. Beam steering technology in the THz range by a fixed structure and frequency sweep has to date lacked a device combining high efficiency and a wide beam steering angle. A subwavelength structure using float zone Si, a low-loss dielectric, could combine both of these aspects, but no experimental demonstration in the THz range has been performed to our knowledge. The BS-SWG was designed with an efficiency of 0.708 at 0.4 THz and beam steering angles of −72.1°–−34.8° by sweeping the incident frequency from 0.3 THz to 0.5 THz including the Beyond 5 G/6 G communication bands. An efficiency of 0.354 at 0.400 THz and beam steering angles of −74°–−34° were experimentally achieved, demonstrating the potential of high-efficiency, wide-angle beam steering for THz communications, imaging, and radar applications.