Open AccessFolded cavity SOI microring sensors for high sensitivity and real time measurement of biomolecular binding
Author(s) -
DanXia Xu,
A. Densmore,
A. Delâge,
P. Waldron,
Ross McKin,
Siegfried Janz,
J. Lapointe,
Gregory P. Lopinski,
T. Mischki,
E. Post,
Pavel Cheben,
Jens H. Schmid
Publication year - 2008
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.16.015137
Subject(s) - resonator , optics , streptavidin , spiral (railway) , resonance (particle physics) , waveguide , materials science , sensitivity (control systems) , coupling (piping) , silicon on insulator , q factor , optofluidics , biosensor , whispering gallery wave , optoelectronics , physics , biotin , chemistry , nanotechnology , microfluidics , mathematical analysis , biochemistry , mathematics , particle physics , electronic engineering , silicon , metallurgy , engineering
We demonstrate folded waveguide ring resonators for biomolecular sensing. We show that extending the ring cavity length increases the resonator quality factor, and thereby enhances the sensor resolution and minimum level of detection, while at the same time relaxing the tolerance on the coupling conditions to provide stable and large resonance contrast. The folded spiral path geometry allows a 1.2 mm long ring waveguide to be enclosed in a 150 microm diameter sensor area. The spiral cavity resonator is used to monitor the streptavidin protein binding with a detection limit of approximately 3 pg/mm(2), or a total mass of approximately 5 fg. The real time measurements are used to analyze the kinetics of biotin-streptavidin binding.