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Proceedings Paper

Tilted optical trapping of anisotropic single crystal nanorod (Presentation Recording)
Author(s): Paul Brule-Bareil; Yunlong Sheng

Paper Abstract

When a nanorod of typically d=100's nm diameter and h=1-3 micrometers length trapped in the optical tweezers, its orientation is along the trapping beam axis for h/d > 2 and is normal to beam axis for h/d < 2. We report the preliminary experimental observation that some anisotropic single crystal nanorod was stably trapped at a tiled angle to the beam axis. We explain the observation with the T-matrix calculation. In the anisotropic media, as the divergence of is non zero, the conventional vector spherical wave functions (VSWFs) do not individually satisfy the anisotropic vector wave equation. Some new bases, such as the modified VSWFS and qVSWF, have been proposed. Notice that the anisotropic nanorod is floating in the aquatic isotropic medium, we make the VSWF expansions of the incident and scattered fields in terms of, and the VSWF expansion of internal field in the anisotropic nanorod in terms of. Both expansions are therefore legitimate. The boundary condition was chosen as for the normal components of. The internal field is represented as a sum of a set of compoment VSWF expansions to gave better description with more expansion coefficients and to help the convergence of the T-matrix solver. Our calculation showed that when the optical axes of an anisotropic nanorod are not aligned to the nanorod axis, the nanorod may be trapped at a tilted angle position where the lateral torque is zero and its derivative is negative.

Paper Details

Date Published: 5 October 2015
PDF: 1 pages
Proc. SPIE 9548, Optical Trapping and Optical Micromanipulation XII, 95481Y (5 October 2015); doi: 10.1117/12.2188458
Show Author Affiliations
Paul Brule-Bareil, Univ. Laval (Canada)
Yunlong Sheng, Univ. Laval (Canada)

Published in SPIE Proceedings Vol. 9548:
Optical Trapping and Optical Micromanipulation XII
Kishan Dholakia; Gabriel C. Spalding, Editor(s)

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