We demonstrate highly efficient evanescent-wave detection of fluorophore-labeled biomolecules in aqueous solutions positioned in the air holes of the microstructured part of a photonic crystal fiber. The air-suspended silica structures located between three neighboring air holes in the cladding crystal guide light with a large fraction of the optical field penetrating into the sample even at wavelengths in the visible range. An effective interaction length of several centimeters is obtained when a sample volume of less than 1μL is used.
© 2004 Optical Society of America
(060.2370) Fiber optics and optical communications : Fiber optics sensors
(230.3990) Optical devices : Micro-optical devices
(300.1030) Spectroscopy : Absorption
(300.6550) Spectroscopy : Spectroscopy, visible
Jesper B. Jensen, Lars H. Pedersen, Poul E. Hoiby, Lars B. Nielsen, T. P. Hansen, J. R. Folkenberg, J. Riishede, Danny Noordegraaf, Kristian Nielsen, A. Carlsen, and A. Bjarklev, "Photonic crystal fiber based evanescent-wave sensor for detection of biomolecules in aqueous solutions," Opt. Lett. 29, 1974-1976 (2004)