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

T. Suzuki; T. Katagiri; Y. Matsuura

doi:10.1117/12.2288102

13 February 2018 Terahertz gas sensing based on time-domain-spectroscopy using a hollow-optical fiber gas cell

T. Suzuki, T. Katagiri, Y. Matsuura

Proceedings Volume 10488, Optical Fibers and Sensors for Medical Diagnostics and Treatment Applications XVIII; 1048808 (2018) https://doi.org/10.1117/12.2288102
Event: SPIE BiOS, 2018, San Francisco, California, United States

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.

Conference Presentation

Citation Download Citation

T. Suzuki, T. Katagiri, and Y. Matsuura "Terahertz gas sensing based on time-domain-spectroscopy using a hollow-optical fiber gas cell", Proc. SPIE 10488, Optical Fibers and Sensors for Medical Diagnostics and Treatment Applications XVIII, 1048808 (13 February 2018); https://doi.org/10.1117/12.2288102

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available