Optofluidic particle concentration by a long-range dual-beam trap.
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.
Kühn
S
S
School of Engineering, University of California Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA.
Lunt
E J
EJ
Phillips
B S
BS
Hawkins
A R
AR
Schmidt
H
H
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
D003102:Colloids