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Long-distance axial trapping with focused annular laser beams.

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.

SUBMITTER: Lei M

PROVIDER: S-EPMC3591451 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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Long-distance axial trapping with focused annular laser beams.

Lei Ming M Li Ze Z Yan Shaohui S Yao Baoli B Dan Dan D Qi Yujiao Y Qian Jia J Yang Yanlong Y Gao Peng P Ye Tong T

PloS one 20130307 3

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 ...[more]

PMID: 23505449

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