Infrared absorptance of wavelength-selection trapezoid grating

Jyh Rou Sze, An Chi Wei, Fong Zhi Chen

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


The wavelength-selection trapezoid gratings which can improve the infrared absorptance contrast are demonstrated. The spectral absorptance of silicon trapezoid grating is studied by using the rigorous coupled-wave analysis (RCWA) numerical scheme. The optical performance of the trapezoid gratings with different side-wall slopes on the groove ridge is calculated and analyzed. According to the analyzed results, the side-wall slope of the trapezoid grating plays an important role for enhancing the contrast of the infrared absorptance. It is found that the absorptance peak is located at the wavelength of 7.0 μm, which is equal to the period of the trapezoid grating. The maximum spectral absorptance contrast is given at the proper side-wall slope of groove ridge of the trapezoid gratings. The influences of the oblique incident light are also analyzed. When the incident angle increases, the absorptance peak deviates from the original location of the normal incident condition. The absorptance peak not only decreases its magnitude but also be split.

Original languageEnglish
Title of host publicationMetamaterials
Subtitle of host publicationFundamentals and Applications IV
StatePublished - 2011
EventMetamaterials: Fundamentals and Applications IV - San Diego, CA, United States
Duration: 21 Aug 201125 Aug 2011

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceMetamaterials: Fundamentals and Applications IV
Country/TerritoryUnited States
CitySan Diego, CA


  • Infrared absorptance contrast
  • Side-wall slope
  • Trapezoid grating


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