title: Scattering detection using a photonic-microfluidic integrated device with on-chip collection capabilities.
abstract: SU-8-based photonic-microfluidic integrated devices with on-chip beam shaping and collection capabilities were demonstrated in a scattering detection and counting application. Through the proper deployment of the tailored beam geometries via the on-chip excitation optics, excellent CV values were measured for 1, 2, and 5 μm blank beads, 16.4, 11.0, and 12.5%, respectively, coupled with a simple free-space optical detection scheme. The performance of these devices was found dependent on the combination of on-chip, lens-shaped beam geometry and bead size. While very low CVs were obtained when the combination was ideal, a nonideal combination could still result in acceptable CVs for flow cytometry; the reliability was confirmed via devices being able to resolve separate populations of 2.0 and 5.0 μm beads from their mixture with low CV values of 15.9 and 18.5%, respectively. On-chip collection using integrated on-chip optical waveguides was shown to be very reliable in comparison with a free-space collection scheme, yielding a coincident rate of 94.2%. A CV as low as 19.2% was obtained from the on-chip excitation and collection of 5 μm beads when the on-chip lens-shaped beam had a 6.0-μm beam waist.
authors.affiliation: Department of Engineering Physics, McMaster University, Hamilton, Canada.
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Watts
authors.forename: Zhiyi
authors.initials: Z
authors.lastname: Zhang
authors.forename: Chang Qing
authors.initials: CQ
authors.lastname: Xu
authors.forename: Xudong
authors.initials: X
authors.lastname: Cao
authors.forename: Min
authors.initials: M
authors.lastname: Lin
mesh_terms: D004553:Electric Conductivity; D004867:Equipment Design; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D008863:Microspheres; D055095:Optics and Photonics / Q000295:instrumentation*; D015203:Reproducibility of Results
keywords: Integrated optics; Lab-on-a-chip; Microfluidic devices; Optofluidics; Scatter detection