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Proceedings Paper

Theoretical research and comparison of forces in optical tweezers based on ray optics method and T matrix method
Author(s): Zhenggang Li; Huizhu Hu; ZhenHai Fu; Qi Zhu; Yu Shen
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Paper Abstract

Based on ray tracing method of ray optics (RO) theory and T-matrix method of electromagnetic scattering theory, we establish optical trap force model and calculate the optical trap force of trapped microspheres whose size is in the beam wavelength scale. Calculation results of axial and transverse trapping efficiency based on the two models agree qualitatively, but differ quantitatively. Then we introduce a trapping efficiency calculation deviation parameter to characterize the difference between these two methods, and analyze how the deviation parameter is influenced by trapped microsphere radius and trapping beam waist radius. Simulation result shows that best agreement between RO model and T matrix calculation method is met when a strongly focused laser beam traps a large microsphere in near the beam waist plane area. In such cases both ray optics approximation conditions and T matrix method approximate conditions are satisfied. Numerical results coincide well with theoretical expectations.

Paper Details

Date Published: 19 October 2016
PDF: 10 pages
Proc. SPIE 10155, Optical Measurement Technology and Instrumentation, 101551F (19 October 2016); doi: 10.1117/12.2246489
Show Author Affiliations
Zhenggang Li, Zhejiang Univ. (China)
Huizhu Hu, Zhejiang Univ. (China)
ZhenHai Fu, Zhejiang Univ. (China)
Qi Zhu, Zhejiang Univ. (China)
Yu Shen, Zhejiang Univ. of Science and Technology (China)

Published in SPIE Proceedings Vol. 10155:
Optical Measurement Technology and Instrumentation
Sen Han; JiuBin Tan, Editor(s)

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