title: Photonic crystal resonator integrated in a microfluidic system.
abstract: We report on a novel optofluidic system consisting of a silica-based 1D photonic crystal, integrated planar waveguides, and electrically insulated fluidic channels. An array of pillars in a microfluidic channel designed for electrochromatography is used as a resonator for on-column label-free refractive index detection. The resonator was fabricated in a silicon oxynitride platform, to support electro-osmotic flow, and operated at lambda=1.55 microm. Different aqueous solutions of ethanol with refractive indices ranging from n=1.3330 to 1.3616 were pumped into the column/resonator, and the transmission spectra were recorded. Linear shifts of the resonant wavelengths yielded a maximum sensitivity of Deltalambda/Deltan=480 nm/RIU (refractive index unit), and a minimum difference of Deltan=0.007 RIU was measured.
authors.affiliation: Department of Micro- and Nanotechnology, Technical University of Denmark, Lyngby, Denmark. pedro.nunes@nanotech.dtu.dk
authors.forename: P S
authors.initials: PS
authors.lastname: Nunes
authors.forename: N A
authors.initials: NA
authors.lastname: Mortensen
authors.forename: J P
authors.initials: JP
authors.lastname: Kutter
authors.forename: K B
authors.initials: KB
authors.lastname: Mogensen