Terahertz broadband anti-reflection moth-eye structures fabricated by femtosecond laser processing

Haruyuki Sakurai, Natsuki Nemoto, Kuniaki Konishi, Ryota Takaku, Yuki Sakurai, Nobuhiko Katayama, Tomotake Matsumura, Junji Yumoto, Makoto Kuwata-Gonokami

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


Anti-reflection (AR) coatings aiming at the reduction of Fresnel reflection losses has come into demand in the terahertz (THz) region. Implementation of such a coating in practice is a difficult task, partially because the broad spectrum of the THz signal is difficult to control. Here, we propose and demonstrate a moth-eye AR structure capable of suppressing reflection losses in the range of 0.3 to 2.5 THz for high-resistivity silicon, resulting in a maximum transmission of 91%. The structure comprises of pyramid-like structures with a height of about 100 µm created on the material surface by femtosecond laser processing. We demonstrate experimentally and theoretically that such micromachining considerably increases transmittance of the silicon in the spectral range of 0.3-2.5 THz. We also demonstrate experimentally that such a structure allows one to improve performance of the THz source based on the LiNbO3 crystal.

Original languageEnglish
Pages (from-to)2764-2772
Number of pages9
JournalOSA Continuum
Issue number9
Publication statusPublished - Sept 15 2019
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


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