Radially polarized beams, focused by a high numerical aperture （NA） objective, have non-propagating fields along the propagation axis in the focal region, which leads to a higher axial trapping efficiency in compari...Radially polarized beams, focused by a high numerical aperture （NA） objective, have non-propagating fields along the propagation axis in the focal region, which leads to a higher axial trapping efficiency in comparison with linearly polarized beams. We propose a design for converting a lowest-order radially polarized beam （R-TEM01） to a double-ring radial polarization distribution （DR R-TEM01） through a specially designed polarization rotator. The phases of the two rings of this beam differ by π. Numerical results evaluated by rigorous T-matrix method show that the DR R-TEM01 beam can improve the axial trapping efficiency compared with the R-TEM01 beam, provided that the size of trapped particles is of order of the wavelength of the beam.展开更多
基金Supported by the National Natural Science Foundation of China under grant No 10874240, and the Shaanxi Province 13115 Science and Technology Innovative Project under grant No 2008ZDKG-68.
文摘Radially polarized beams, focused by a high numerical aperture （NA） objective, have non-propagating fields along the propagation axis in the focal region, which leads to a higher axial trapping efficiency in comparison with linearly polarized beams. We propose a design for converting a lowest-order radially polarized beam （R-TEM01） to a double-ring radial polarization distribution （DR R-TEM01） through a specially designed polarization rotator. The phases of the two rings of this beam differ by π. Numerical results evaluated by rigorous T-matrix method show that the DR R-TEM01 beam can improve the axial trapping efficiency compared with the R-TEM01 beam, provided that the size of trapped particles is of order of the wavelength of the beam.
