Antiresonant fibers with single- and double-ring capillaries for optofluidic applications

In this work we discuss the effect of infiltration of different antiresonant fibers with low-refractive-index liquids, such as water and ethanol, on their optical properties. The fibers with single- and double-ring capillaries have been designed to show broad transmission bands in visible and near infrared range as it is required for optofluidics, in particular spectrophotometric applications. We show experimentally that their transmission windows shift toward shorter wavelengths and only modestly reduce their width. The transmission bands are located in the wavelength ranges of 533-670 nm and 707-925 nm, for the fibers when infiltrated with water. The two types of analyzed antiresonant fibers infiltrated with the liquids show similar light guidance properties when they are straight, but significantly lower bending loss can be achieved for the double-ring than for the single-ring antiresonant fiber. For this reason, the double-ring antiresonant fibers are more suitable as a compact solution for optofluidic applications, although transmission windows are reduced due to broader resonance peaks.