Laser-Based Trace Gas Detection inside Hollow-Core Fibers: A Review

Abstract

Thanks to the guidance of an optical wave in air, hollow-core fibers may serve as sampling cells in an optical spectroscopic system. This paper reviews applications of hollow-core optical fibers to laser-based gas sensing. Three types of hollow-core fibers are discussed: Hollow capillary waveguides, photonic band-gap fibers, and negative curvature fibers. Their advantages and drawbacks when used for laser-based trace gas detection are analyzed. Various examples of experimental sensing systems demonstrated in the literature over the past 20 years are discussed.

Keywords

• hollow-core fiber (HCF)
• negative curvature hollow-core fiber (NC HCF)
• photonic band-gap hollow-core fiber (PBG HCF)
• anti-resonant hollow-core fiber
• Kagome hollow-core fiber
• laser spectroscopy