title: Optofluidic particle concentration by a long-range dual-beam trap.
abstract: Ultrahigh sensitivity detection of particles in solution implies the ability to detect at very low concentrations. At the single-particle level, this is achieved through fluorescence detection, reaching down to single fluorophores. Sensitivity may also be improved by concentrating many particles into a compact cluster, thus "integrating" the signal of many particles. We show how both ways can be combined on an optofluidic chip in a fully planar geometry utilizing counterpropagating liquid-core waveguide modes to form a loss-based optical trap. This all-optical concentrator can increase the concentration of particles by more than 2 orders of magnitude and also provides a convenient, nondispersive means of transport for particle ensembles.
authors: School of Engineering, University of California Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA.
authors: S
authors: S
authors: Kühn
authors: E J
authors: EJ
authors: Lunt
authors: B S
authors: BS
authors: Phillips
authors: A R
authors: AR
authors: Hawkins
authors: H
authors: H
authors: Schmidt
mesh_terms: D003102:Colloids / Q000737:chemistry*; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D044085:Microfluidics / Q000295:instrumentation*; D008856:Microscopy, Fluorescence / Q000295:instrumentation; D052898:Optical Tweezers; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003102:Colloids