Title: Optimization of probe-laser focal offsets for single-particle tracking
Authors: Chang, Ai-Tang
Chang, Yi-Ren
Chi, Sien
Hsu, Long
Department of Electrophysics
Department of Photonics
Issue Date: 1-Jan-1970
Abstract: "In optical tweezers applications, tracking a trapped particle is essential for force measurement. One of the most popular techniques for single-particle tracking is achieved by analyzing the forward and backward light pattern, scattered by the target particle trapped by a trap laser beam, of an additional probe-laser beam with different wavelength whose focus is slightly apart from the trapping center. However, the optimized focal offset has never been discussed. In this paper, we investigate the tracking range and sensitivity as a function of the focal offset between the trapping and the probe-laser beams. As a result, the optimized focal offsets are a 3.3-fold radius ahead and a 2.0-fold radius behind the trapping laser focus in the forward tracking and the backward tracking, respectively. The experimental result agrees well with a theoretical prediction using the Mie scattering theory. (C) 2012 Optical Society of America"
URI: http://hdl.handle.net/11536/16733
ISSN: 1559-128X
Volume: 51
Issue: 23
End Page: 5643
Appears in Collections:Articles