Compact Metasurface Terahertz Spectrometer

Laser & Photonics Review, vol. 19

Abstract

Abstract The terahertz frequency region of the electromagnetic spectrum is crucial for understanding the formation and evolution of galaxies and stars throughout the universe's history, as well as the process of planet formation. Detecting the unique spectral signatures of molecules and atoms requires terahertz spectrometers, which must be operated in space observatories due to water vapor absorption in the Earth's atmosphere. However, current terahertz spectrometers face challenges such as low resolution, limited bandwidth, large volume, and complexity. In this paper, the issues of size and weight are addressed by demonstrating a concept for a centimeter‐sized, low‐weight terahertz spectrometer using a metasurface. The design of the metasurface spectrometer is first discussed for the 1.85 to 2.4 THz range, followed by its fabrication. Next, an array of quantum cascade lasers operating at slightly different frequencies around 2.1 THz is utilized to characterize the spectrometer. Finally, a spectrum inversion method is applied to analyze the measured data, confirming a resolution R (λ/Δλ) of at least 273. This concept can be extended to other application areas, such as planetary observations and various wavelengths in the far‐infrared (FIR) and near‐infrared (NIR) ranges.

Authors 10

1. Wenye Ji corresponding

   Delft University of Technology

   Affiliation as printed

   Department of Imaging Physics Delft University of Technology Lorentzweg 1 Delft 2628 CJ The Netherlands

2. Jin Chang

   Delft University of Technology

   Affiliation as printed

   Department of Quantum Nanoscience Delft University of Technology Lorentzweg 1 Delft 2628 CJ The Netherlands

3. B. Mirzaei

   Delft University of Technology

   Affiliation as printed

   Department of Imaging Physics Delft University of Technology Lorentzweg 1 Delft 2628 CJ The Netherlands

4. M. Ridder Aachen SRON Netherlands Institute for Space Research Niels Bohrweg 4

   Space Research Organisation Netherlands

   Affiliation as printed

   SRON Netherlands Institute for Space Research Niels Bohrweg 4, 2333 CA Leiden and Landleven 12 Groningen 9747 AD The Netherlands

5. Willem Jellema Aachen SRON Netherlands Institute for Space Research Niels Bohrweg 4

   Space Research Organisation Netherlands

   Affiliation as printed

   SRON Netherlands Institute for Space Research Niels Bohrweg 4, 2333 CA Leiden and Landleven 12 Groningen 9747 AD The Netherlands

6. T. Y. Kao
   Affiliation as printed

   LongWave Photonics LLC Mountain View CA 94043 USA

7. Alan Lee
   Affiliation as printed

   LongWave Photonics LLC Mountain View CA 94043 USA

8. J. R. Gao Aachen SRON Netherlands Institute for Space Research Niels Bohrweg 4

   Space Research Organisation Netherlands · Delft University of Technology

   Affiliation as printed

   Department of Imaging Physics Delft University of Technology Lorentzweg 1 Delft 2628 CJ The Netherlands

   SRON Netherlands Institute for Space Research Niels Bohrweg 4, 2333 CA Leiden and Landleven 12 Groningen 9747 AD The Netherlands

9. Hendrik Paul Urbach

   Delft University of Technology

   Affiliation as printed

   Department of Imaging Physics Delft University of Technology Lorentzweg 1 Delft 2628 CJ The Netherlands

10. Aurèle J. L. Adam

    Delft University of Technology

    Affiliation as printed

    Department of Imaging Physics Delft University of Technology Lorentzweg 1 Delft 2628 CJ The Netherlands