Application of silicon micropyramid structures for antireflection of terahertz waves

Pengyu Han, Yuting W. Chen, Xi Cheng Zhang

Research output: Contribution to journalArticlepeer-review


Reflection from silicon-based terahertz (THz) components degrades the performance of THz spectroscopy systems by inducing loss and interference. In this paper, we report the design, fabrication, and demonstration of silicon-based devices for reflection reduction and transmission enhancement of broadband THz electromagnetic waves. Antireflection (AR) effect is achieved in the broad frequency range of 0.23.15 THz using silicon micropyramid structures as the AR devices. We observe a maximum of 89 reduction in reflectivity of THz power when the sample with 60-μm-period micropyramids is used, compared with the reflectivity of a planar silicon substrate. By varying the period of the micropyramid devices from 110 to 30 μm, the cut-off frequency of enhanced transmission is tuned from 0.74 to 2.93 THz and the bandwidth of enhancement increases from 0.91 to 3.15 THz, respectively. Although the structures have been demonstrated as AR devices for silicon substrate, this design can be also used for other substrate materials. Furthermore, the silicon devices also function as low-pass filters.

Original languageEnglish (US)
Article number5280379
Pages (from-to)338-343
Number of pages6
JournalIEEE Journal on Selected Topics in Quantum Electronics
Issue number1
StatePublished - Jan 2010
Externally publishedYes


  • Antireflection
  • Crystallographic etching
  • Low-pass filter
  • Micropyramid
  • Terahertz spectroscopy

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

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