Improvement in THz light extraction efficiencies with antireflection subwavelength gratings on a silicon prism

Ying Huang, Atsuki Kosugi, Yuya Naito, Yuma Takida, Hiroaki Minamide, Kazuhiro Hane, Yoshiaki Kanamori

Research output: Contribution to journalArticlepeer-review

Abstract

An antireflection (AR) structure that incorporates a subwavelength grating (SWG) is a promising candidate for suppressing the Fresnel reflection of a silicon prism used as a component of an injection-seeded THz wave parametric generator (is-TPG) to improve the efficiency in extracting THz waves. Here, a two-dimensional binary AR-SWG with a 20 μm period is designed and then numerically and experimentally realized. The measured transmittance of the AR-SWG is discovered to be greater than 80% from 0.5 to 4.0 THz and to exceed 90% from 1.25 to 2.83 THz. Moreover, the AR-SWG is tightly attached to the Si prism of the is-TPG by direct-bonding technology. Compared to the is-TPG without AR-SWGs, the output increases by 1.3-1.5 times from 1.09 to 2.52 THz. The improvement in THz light extraction efficiency is thus successfully demonstrated.

Original languageEnglish
Article numberSCCL04
JournalJapanese journal of applied physics
Volume60
Issue numberSC
DOIs
Publication statusPublished - 2021 Jun

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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