Compact Metasurface Terahertz Spectrometer

arXiv (Cornell University)

Abstract

The electromagnetic spectrum in the terahertz frequency region is of significant importance for understanding the formation and evolution of galaxies and stars throughout the history of the universe and the process of planet formation. Within the star forming clouds the constituent atoms and molecules are excited to produce characteristic emission and absorption lines, many of which happen at the terahertz frequencies. Thus, detecting the spectral signatures as unique fingerprints of molecules and atoms require terahertz spectrometers, which need to be operated in a space observatory because of the water vapor absorption in the earth atmosphere. However, current terahertz spectrometers face several challenges that limit their performances and applications, including a low resolution, limited bandwidth, large volume, and complexity. In this paper, we address the last two issues by demonstrating a concept of a compact terahertz spectrometer using metasurface. We start by modelling, designing, and fabricating a metasurface, aiming to optimize its performance within a band from 1.7 to 2.5 THz. Next, we make use of an array of quantum cascade lasers that operate at slightly different frequencies around 2.1 THz to validate the performance of the spectrometer. Finally, we apply the spectrum inversion method to analyse the measured data to confirm a resolution R of at least 273. Our results demonstrated a miniaturized terahertz spectrometer concept successfully.

Authors 9

1. Wenye Ji

   Delft University of Technology

   Affiliation as printed

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

2. Jin Chang

   Delft University of Technology

   Affiliation as printed

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

3. B. Mirzaei

   Delft University of Technology

   Affiliation as printed

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

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

   Space Research Organisation Netherlands

   Affiliation as printed

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

5. Willem Jellema Aachen SRON Netherlands Institute for Space Research

   Space Research Organisation Netherlands

   Affiliation as printed

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

6. Alan Lee
   Affiliation as printed

   . LongWave Photonics LLC , Mountain View CA 94043 , USA

7. J. R. Gao Aachen SRON Netherlands Institute for Space Research

   Space Research Organisation Netherlands · Delft University of Technology

   Affiliation as printed

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

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

8. Paul Urbach

   Delft University of Technology

   Affiliation as printed

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

9. Aurèle J. L. Adam

   Delft University of Technology

   Affiliation as printed

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