We present a detailed theoretical discussion and experimental analysis of an interferometric optical trapping device that allows efficient sorting of particles, including biological samples, either by size or refractive index. This technique involves no microfluidic flow, but it is based on the specific response of different microparticles to an interference pattern of fringes vibrating with a periodic but non-symmetric time modulation function. The performance of the system is analyzed in terms of the different control parameters, such as the period of the fringes, the vibration amplitude and frequency, and the power level in the sample. We discuss the possibility of using this system to characterize unknown samples.

Date Published: 11 September 2006
PDF: 9 pages
Proc. SPIE 6326, Optical Trapping and Optical Micromanipulation III, 632616 (11 September 2006); doi: 10.1117/12.679857

Published in SPIE Proceedings Vol. 6326:
Optical Trapping and Optical Micromanipulation III
Kishan Dholakia; Gabriel C. Spalding, Editor(s)