We propose and demonstrate the possibility of using a permanently microbent bare optical fiber for detecting chemical species. Two detection schemes, viz., a bright-field detection scheme (for the core modes), and a dark-field detection scheme (for the cladding modes) have been employed to produce a fiber-optic sensor. The sensor described here is sensitive enough to detect concentrations as low as nanomoles per liter of a chemical species, with a dynamic range of more than 6 orders of magnitude.
© 2001 Optical Society of America
Thomas Lee S, Nibu A. George, P. Sureshkumar, P. Radhakrishnan, C. P. G. Vallabhan, and V. P. N. Nampoori, "Chemical sensing with microbent optical fiber," Opt. Lett. 26, 1541-1543 (2001)