中国物理B ›› 2006, Vol. 15 ›› Issue (6): 1391-1397.doi: 10.1088/1009-1963/15/6/044

• • 上一篇    

Systematical study of the trapping forces of optical tweezers formed by different types of optical ring beams

楼立人1, 徐升华2, 李银妹2   

  1. (1)Department of Physics, University of Science and Technology of China, Hefei 230026 China; (2)National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China;Department of Physics, University of Science and Technology of China, Hefei 230026 China
  • 收稿日期:2005-07-06 修回日期:2006-02-24 出版日期:2006-06-20 发布日期:2006-06-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos 20273065 and 10474094) and `the Knowledge Innovation Program' of Chinese Academy of Sciences.

Systematical study of the trapping forces of optical tweezers formed by different types of optical ring beams

Xu Sheng-Hua (徐升华)ab, Li Yin-Mei (李银妹)ab, Lou Li-Ren (楼立人)b    

  1. a National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China; b Department of Physics, University of Science and Technology of China, Hefei 230026, China
  • Received:2005-07-06 Revised:2006-02-24 Online:2006-06-20 Published:2006-06-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos 20273065 and 10474094) and `the Knowledge Innovation Program' of Chinese Academy of Sciences.

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摘要： The technique of optical tweezers has been improved a lot since its invention, which extends the application fields of optical tweezers. Besides the conventionally used Gaussian beams, different types of ring beams have also been used to form optical tweezers for different purposes. The two typical kinds of ring beams used in optical tweezers are the hollow Gaussian beam and Laguerre--Gaussian (LG) beam. Both theoretical computation and experiments have shown that the axial trapping force is improved for the ring beams compared with the Gaussian beam, and hence the trapping stability is improved, although the transverse trapping forces of ring beams are smaller than that of Gaussian beam. However, no systematic study on the trapping forces of ring beam has ever been discussed. In this article, we will investigate the axial and transverse trapping forces of different types of ring beams with different parameters systematically, by numerical computation in which the ray optics model is adopted. The spherical aberration caused by the refractive index mismatch between oil and water is also considered in the article. The trapping forces for different objectives that obey the sine condition and tangent condition are also compared with each other. The result of systematical calculation will be useful for the applications of optical tweezers formed by different types of ring beams.

关键词: optical tweezers, trapping force, spherical aberration

Abstract: The technique of optical tweezers has been improved a lot since its invention, which extends the application fields of optical tweezers. Besides the conventionally used Gaussian beams, different types of ring beams have also been used to form optical tweezers for different purposes. The two typical kinds of ring beams used in optical tweezers are the hollow Gaussian beam and Laguerre--Gaussian (LG) beam. Both theoretical computation and experiments have shown that the axial trapping force is improved for the ring beams compared with the Gaussian beam, and hence the trapping stability is improved, although the transverse trapping forces of ring beams are smaller than that of Gaussian beam. However, no systematic study on the trapping forces of ring beam has ever been discussed. In this article, we will investigate the axial and transverse trapping forces of different types of ring beams with different parameters systematically, by numerical computation in which the ray optics model is adopted. The spherical aberration caused by the refractive index mismatch between oil and water is also considered in the article. The trapping forces for different objectives that obey the sine condition and tangent condition are also compared with each other. The result of systematical calculation will be useful for the applications of optical tweezers formed by different types of ring beams.

Key words: optical tweezers, trapping force, spherical aberration

中图分类号:  (Mechanical effects of light on atoms, molecules, and ions)

  • 37.10.Vz
42.15.Fr (Aberrations) 42.60.Da (Resonators, cavities, amplifiers, arrays, and rings) 42.60.Jf (Beam characteristics: profile, intensity, and power; spatial pattern formation)