Infrared hollow fibers were developed for spectroscopic gas sensing.The hollow core fiber has a silver film and a dielectric film on its inner surface to enhance the reflection rate,and thus to low the transmission loss.The chemical silver mirror-reaction method and the liquid-phase coating technique were used to form the silver and the dielectric film.Low-loss properties were achieved from the visible to the mid-infrared wavelength regions by optimizing the dielectric material and the film thickness.The lo...