title: Nanofiber optic sensor based on the excitation of surface plasmon wave near fiber tip.
abstract: We present a sensitive nano-optical fiber biosensor made by shaping a fiber to form a taper with a tip size under 100 nm. A 40-nm-thick layer of gold is coated around the tapered fiber and a surface plasmon wave is excited near the tip to achieve a sensitivity of the reflective index unit of approximately 4000 (% RIU(-1)) in the intensity measurement. A 3-D coded finite-difference time-domain approach verifies the excitation of the surface plasmon wave and the differences among its intensities in media of various refractive indices. The nanotip fiber sensor has the merits of a low background light and an ultrasmall detection region. Only a microliter of sample solution is required for detection.
authors.affiliation: Academia Sinica, Research Center for Applied Sciences, 128, section 2, Academia Road, Nankang, Taipei 11529, Taiwan.
authors.forename: Yu-Jen
authors.initials: YJ
authors.lastname: Chang
authors.forename: Yi-Chun
authors.initials: YC
authors.lastname: Chen
authors.forename: Hui-Ling
authors.initials: HL
authors.lastname: Kuo
authors.forename: Pei-Kuen
authors.initials: PK
authors.lastname: Wei
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D003198:Computer Simulation; D017076:Computer-Aided Design; D005336:Fiber Optic Technology / Q000295:instrumentation*; D008962:Models, Theoretical; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D055100:Optical Fibers; D020349:Surface Plasmon Resonance / Q000295:instrumentation* / Q000379:methods; D014159:Transducers