Broadband optical filter based on high purity isotope gas for the carbon-13 breath test

• Published in: Journal of the Korean Physical Society Vol. 83; no. 11; pp. 842 - 847
• Main Authors: Chun, Byung Jae, Lee, Lim, Ko, Kwang-Hoon, Kim, Yonghee, Kim, Taek-Soo, Park, Seung-Kyu, Park, Hyunmin
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Physical Society 01-12-2023; Springer Nature B.V; 한국물리학회
• Subjects: Broadband; Carbon 13; Carbon isotopes; Infrared filters; Infrared spectroscopy; Mathematical and Computational Physics; Molecules and Optics; Optical filters; Original Paper - Atoms; Particle and Nuclear Physics; Physics; Physics and Astronomy; Purity; Theoretical; 물리학; Carbon-13; Breath Test; NDIR Spectroscopy; Mid-IR; Optical filter
• ISSN: 0374-4884; 1976-8524
• DOI: 10.1007/s40042-023-00951-2

In this study, we developed a novel isotope gas filter for a mid-infrared (IR) LED-based NDIR spectroscopy system. Our novel isotope gas filter contains high-purity CO
2
gas (99.99% content), and the intrinsic absorption characteristic of contained gas works as an optical stopband filter. Our filter achieves a 25 dB attenuation performance in the region of 4190–4350 nm, and is a core component in distinguishing the signal from different carbon isotopes such as
12
CO
2
and
13
CO
2
for an NDIR carbon-13 (C-13) based breath test. Compared with dielectric filters normally used for C-13 breath tests, our filter can provide more useful and consistent performance than dielectric filters in the mid-IR region.