title: Ultrasensitive label-free coupled optofluidic ring laser sensor.
abstract: A coupled optofluidic ring laser sensor is fabricated, and its ultrasensitive bulk refractive index and surface mass sensing properties are demonstrated. The sensor consists of a cylindrical ring laser and a thin-walled optofluidic capillary ring resonator. Coupling of the whispering gallery mode in the two resonators generates a largely magnified sensitivity due to the Vernier effect. A sensitivity of 2510 nm/RIU and magnification factor of 355 are achieved experimentally in aqueous solution, which corresponds to a noise equivalent detection limit of 1.6×10(-5) RIU for bulk RI detection. The new sensor configuration provides a convenient way to achieve ultrasensitive biological and chemical sensing.
authors.affiliation: Key Laboratory for Micro and Nanophotonic Structures (Ministry of Education), Department of Optical Science and Engineering, School of Information Science and Engineering, Fudan University, Shanghai, China.
authors.forename: Liqiang
authors.initials: L
authors.lastname: Ren
authors.forename: Xiang
authors.initials: X
authors.lastname: Wu
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Xingwang
authors.initials: X
authors.lastname: Zhang
authors.forename: Liying
authors.initials: L
authors.lastname: Liu
authors.forename: Lei
authors.initials: L
authors.lastname: Xu
mesh_terms: D001704:Biopolymers / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D044085:Microfluidics / Q000295:instrumentation*; D012031:Refractometry / Q000295:instrumentation*; D013194:Staining and Labeling; D014159:Transducers
chemical_list: D001704:Biopolymers