Boundary element method for optical force calibration in microfluidic dual-beam optical trap

Date
2015
Advisor
Supervisor
Co-Advisor
Co-Supervisor
Instructor
Source Title
Proceedings of SPIE
Print ISSN
0277-786X
Electronic ISSN
Publisher
SPIE
Volume
9548
Issue
Pages
Language
English
Type
Conference Paper
Journal Title
Journal ISSN
Volume Title
Series
Abstract

The potential use of optical forces in microfluidic environment enables highly selective bio-particle manipulation. Manipulation could be accomplished via trapping or pushing a particle due to optical field. Empirical determination of optical force is often needed to ensure efficient operation of manipulation. The external force applied to a trapped particle in a microfluidic channel is a combination of optical and drag forces. The optical force can be found by measuring the particle velocity for a certain laser power level and a multiplicative correction factor is applied for the proximity of the particle to the channel surface. This method is not accurate especially for small microfluidic geometries where the particle size is in Mie regime and is comparable to channel cross section. In this work, we propose to use Boundary Element Method (BEM) to simulate fluid flow within the micro-channel with the presence of the particle to predict drag force. Pushing experiments were performed in a dual-beam optical trap and particlea's position information was extracted. The drag force acting on the particle was then obtained using BEM and other analytical expressions, and was compared to the calculated optical force. BEM was able to predict the behavior of the optical force due to the inclusion of all the channel walls. © 2015 SPIE.

Course
Other identifiers
Book Title
Keywords
Microuidics, Drag, Flow of fluids, Laser optics, Microfluidics, Micromanipulators, Particle size, Sailing vessels, Velocity control, Analytical expressions, Channel cross section, Microfluidic environment, Microfluidic geometry, Microuidics, Multiplicative corrections, Optical force, Opticaltrapping, Boundary element method
Citation
Published Version (Please cite this version)