Broadband infrared metamaterial absorber with raindrop-shaped submicron-scale disk array

Wei Jia, Jing Bai, Kevin Roberts, David Gosztola, Gary Wiederrecht, Debao Zhou

Research output: Chapter in Book/Report/Conference proceedingConference contribution


In this paper, we present results from our theoretical and experimental exploration of tailoring the absorption spectrum of a type of metamaterial absorber through manipulating the symmetricity and uniformity of the metallic submicron particle array on the top layer. The absorber under study is a metal-insulator-metal (MIM) trilayer structure made up of a top layer of engineered metallic submicron particles, a middle insulator spacer layer and an opaque ground metal reflector layer. We first studied the structure with a top layer consisting of a uniform array of raindrop-shaped gold (Au) submicron disks. We designed the raindrop shape with a reflectional symmetry on the 45° line. We compared the spectrum generated with that of a similar structure but the top layer which is filled with uniformly arranged circular submicron discs. It has been well reported that an array of circular particles each with both reflectional and rotational symmetries usually generates a spectrum with one absorption spike. By changing the circular shape to raindrop shape, the MIM absorber has been predicted to generate two absorption peaks with significantly broadened absorption bandwidth. Subsequently, we found that even wider spectra could be achieved if the top layer is built with a periodic arrangement of the unit cells containing differently sized raindrop-shaped disks. This leads to a wider bandwidth of higher than 50% absorbance ranging from 2.80 μm to 3.90 μm.

Original languageEnglish (US)
Title of host publicationPhysics and Simulation of Optoelectronic Devices XXVIII
EditorsBernd Witzigmann, Marek Osinski, Yasuhiko Arakawa
ISBN (Electronic)9781510633117
StatePublished - 2020
EventPhysics and Simulation of Optoelectronic Devices XXVIII 2020 - San Francisco, United States
Duration: Feb 3 2020Feb 6 2020

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferencePhysics and Simulation of Optoelectronic Devices XXVIII 2020
Country/TerritoryUnited States
CitySan Francisco

Bibliographical note

Funding Information:
The work is supported by the Grant-in-Aid award (#174244) from the University of Minnesota. Portions of this work were conducted in the Minnesota Nano Center, which is supported by the National Science Foundation through the National Nano Coordinated Infrastructure Network (NNCI) under Award Number ECCS-1542202.

Publisher Copyright:
© 2020 SPIE.


  • Metamaterials
  • and submicron-scale
  • infrared absorber
  • raindrop-shaped


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