Parallel-Plate Waveguide Terahertz Time Domain Spectroscopy for Ultrathin Conductive Films

  • M. RazanoelinaEmail author
  • R. Kinjo
  • K. Takayama
  • I. Kawayama
  • H. Murakami
  • Daniel M. Mittleman
  • M. Tonouchi


Development of techniques for characterization of extremely thin films is an important challenge in terahertz (THz) science and applications. Spectroscopic measurements of materials on the nanometer scale or of atomic layer thickness (2D materials) require a sufficient terahertz wave–matter interaction length, which is challenging to achieve in conventional transmission geometry. Waveguide-based THz spectroscopy offers an alternative method to overcome this problem. In this paper, we investigate a new parallel-plate waveguide (PPWG) technique for measuring dielectric properties of ultrathin gold films, in which we mount the thin film sample at the center of the waveguide. We discuss a model of THz dielectric parameter extraction based on waveguide theory and analyze the response of thin films for both transverse magnetic (TM) and transverse electric (TE) waveguide modes. In contrast to other waveguide methods, our approach enables comparison of the material response with different electromagnetic field distributions without significantly changing the experimental setup. As a result, we demonstrate that TE modes have a better sensitivity to the properties of the thin film. For prototype test samples, optical parameters extracted using our method are in good agreement with literature values.


Thin conductive film Parallel-plate waveguide Terahertz 



This work was supported by JSPS KAKENHI Grant Number 25249049.


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Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  • M. Razanoelina
    • 1
    Email author
  • R. Kinjo
    • 1
  • K. Takayama
    • 1
  • I. Kawayama
    • 1
  • H. Murakami
    • 1
  • Daniel M. Mittleman
    • 1
    • 2
  • M. Tonouchi
    • 1
  1. 1.Institute of Laser EngineeringOsaka UniversityOsakaJapan
  2. 2.Electrical and Computer Engineering DepartmentRice UniversityHoustonUSA

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