Long-distance axial trapping with focused annular laser beams

Ming Lei; Ze Li; Shaohui Yan; Baoli Yao; Dan Dan; Yujiao Qi; Jia Qian; Yanlong Yang; Peng Gao; Tong Ye

doi:10.1371/journal.pone.0057984

Long-distance axial trapping with focused annular laser beams

PLoS One. 2013;8(3):e57984. doi: 10.1371/journal.pone.0057984. Epub 2013 Mar 7.

Authors

Ming Lei¹, Ze Li, Shaohui Yan, Baoli Yao, Dan Dan, Yujiao Qi, Jia Qian, Yanlong Yang, Peng Gao, Tong Ye

Affiliation

¹ State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China.

Abstract

Focusing an annular laser beam can improve the axial trapping efficiency due to the reduction of the scattering force, which enables the use of a lower numerical aperture (NA) objective lens with a long working distance to trap particles in deeper aqueous medium. In this paper, we present an axicon-to-axicon scheme for producing parallel annular beams with the advantages of higher efficiency compared with the obstructed beam approach. The validity of the scheme is verified by the observation of a stable trapping of silica microspheres with relatively low NA microscope objective lenses (NA = 0.6 and 0.45), and the axial trapping depth of 5 mm is demonstrated in experiment.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Lasers*
Lenses
Microspheres
Models, Theoretical*
Optical Tweezers*
Silicon Dioxide

Substances

Silicon Dioxide

Grants and funding

This research is supported by the National Basic Research Program (973 Program) of China under Grant No. 2012CB921900, and the Natural Science Foundation of China (NSFC) under Grant Nos. 61275193, 61205123. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.