Hollow-core anti-resonant optical fibers for chemical and biomedical sensing

Hollow-core anti-resonant optical fiber (HC-ARF) provides solutions for breaking the bottlenecks in areas of high-power transmission and high-efficiency optical waveguide. Other than transporting light wave, HC-ARFs can synergistically combine microfluidics and optics in a single fiber with unprecedented light path length not readily achievable by planar optofluidic configurations. The unique features of strict light confinement, wide transmission band and low transmission loss of HC-ARFs enable high sensing performance with low sample consumption, outcompeting conventional optical assays. In this review, we provide a comprehensive overview of HC-ARFs for label-free molecular sensing. We deliver information on the light propagation mechanism and state-of-the-art structures of HC-ARFs, as well as recent progress in chemical and biomedical sensing mainly covering gas, liquid, DNA and protein sensors along with exosome-based liquid biopsy and cancer cell detection. At the end, challenges and prospects of HC-ARF for sensing applications are discussed.