Advancements in hollow-core anti-resonant fiber for gas sensing applications

Hollow-core anti-resonant fibers (HC-ARFs) have emerged as a transformative platform for high-performance gas sensing. This review systematically summarizes recent advances in HC-ARF-based gas sensors. It begins by elucidating the light-guiding principles of HC-ARFs. Subsequently, key strategies for enhancing sensor performance are discussed, encompassing structural optimization of the fiber, selection of mid-infrared substrate materials, femtosecond laser fabrication of microchannels to accelerate gas diffusion, and surface modification with functional materials for improved selectivity. The core of the review analyzes representative sensing techniques integrated with HC-ARFs, including direct absorption spectroscopy (DAS) and its highly sensitive derivatives, photothermal and photoacoustic spectroscopy, as well as multiplexed Raman spectroscopy. Finally, current challenges and future prospects are outlined, highlighting the potential of HC-ARF sensors to achieve ultra-sensitive, rapid, and compact gas detection for various applications.