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Monday, September 1, 2014

Comparative Analysis of the Trapping Force Using Laguerre-Gaussian Beam and Gaussian Beam

ZHOU Ye-peng, REN Hong-liang, WANG Juan, CHEN Ling
The axial trapping effect of hollow beam such as Laguerre-Gaussian beam is better than that of Gaussian beam. The intensity distributions of Gaussian beam and Laguerre-Gaussian beam were simulated according to their cross-section intensity expression. The trapping Q-factors of Gaussian beam and Laguerre-Gaussian beam were calculated in the ray-optics model. The trapping efficiencies of Gaussian beam and Laguerre-Gaussian beam were compared with different trappped bead size and refractive index, numerical aperture of microscope objective, and the distance from the bottom of the sample cell to the trapped bead. The results show that the maxmium backward trapping Q-factor and trap stiffness of Laguerre-Gaussian beam are higher than those of the Gaussian beam. Laguerre-Gaussian beam is more sensitive to spherical aberration due to its special intensity distribution, especially when the numerical aperture of microscope objective is high.

DOI

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