Terahertz gas sensing based on time-domain-spectroscopy using a hollow-optical fiber gas cell

T. Suzuki, Takashi Katagiri, Yuji Matsuura

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

1 Citation (Scopus)

Abstract

Terahertz gas sensing system based on time-domain spectroscopy (THz-TDS) using a hollow-optical fiber gas cell is proposed. A hollow optical fiber functions as a long-path and low-volume gas cell and loading a dielectric layer on the inside of the fiber reduces the transmission loss and the dielectric layer also protects the metal layer of the fiber from deterioration. In the fabrication process, a polyethylene tube with a thin wall is drawn from a thick preform and a metal layer is formed on the outside of the tube. By using a 34-cm long fiber gas cell, NH3 gas with a concentration of 8.5 % is detected with a good SN ratio. However, the absorption peaks of NH3 and water vapor appeared at around 1.2 THz are not separated. To improve the frequency resolution in Fourier transformation, the time scan width that is decided by the scanning length of linear stage giving a time delay in the probing THz beam is enlarged. As a result, the absorption peaks at around 1.2 THz are successfully separated. In addition, by introducing a longer fiber gas cell of 60-cm length, the measurement sensitivity is improved and an absorption spectrum of NH3 gas with a concentration of 0.5 % is successfully detected.

Original languageEnglish
Title of host publicationOptical Fibers and Sensors for Medical Diagnostics and Treatment Applications XVIII
EditorsIsrael Gannot, Israel Gannot
PublisherSPIE
ISBN (Electronic)9781510614611
DOIs
Publication statusPublished - 2018 Jan 1
EventOptical Fibers and Sensors for Medical Diagnostics and Treatment Applications XVIII 2018 - San Francisco, United States
Duration: 2018 Jan 272018 Jan 28

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume10488
ISSN (Print)1605-7422

Other

OtherOptical Fibers and Sensors for Medical Diagnostics and Treatment Applications XVIII 2018
CountryUnited States
CitySan Francisco
Period18/1/2718/1/28

Keywords

  • Breath analysis
  • Hollow optical fiber
  • Terahertz waveguide
  • Time domain spectroscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology Nuclear Medicine and imaging

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