Recent Advances in Spectroscopic Gas Sensing With Micro/Nano-Structured Optical Fibers

With micro- and nano-structured optical fibers, parts-per-million to parts-per-trillion level gas detection has been demonstrated for a range of gases such as methane, acetylene, ethane, carbon monoxide, hydrogen, and oxygen. We review the recent development in optical fiber gas cells and gas detection systems based on direct absorption, photothermal, photoacoustic, and stimulated Raman spectroscopies.