Debye series analysis of radiation torque exerted on a sphere
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摘要:基于会聚光束所产生的扭矩来实现对小粒子的操纵已在物理学、生物学等领域得到了广泛的应用。为了分离出单个散射过程对扭矩的贡献,给出扭矩物理机理的解释,本文引入德拜级数分析了高斯波束对均匀球粒子所产生的扭矩。计算表明,当德拜项p从1取到一个足够大的值后,德拜级数计算结果与广义米氏理论结果吻合。文中重点分析了单阶p散射过程对横向扭矩的贡献,结果表明:当线极化光束入射时,p=1~5散射过程都可以产生横向扭矩,但扭矩的方向不同;当圆极化光束入射时,p=-1和0对应的扭矩远大于p=1~4对应的扭矩,且p=0过程产生与其他p过程相反方向的扭矩。Abstract:The radiation torque induced by a focused laser beam has been widely utilized for the optical manipulation of small particles in various fields such as physics, biology, and optofluidics. To isolate the contribution of each scattering process to the radiation torque and to clarify the physical mechanism of radiation torque, the Debye Series Expand(DSE) is introduced to analysis of the radiation torque exerted on a homogeneous sphere by Gaussian beam. When Debye mode p ranges from 1 to a value pmax large enough, the result obtained by DSE is identical to that by Generalized Lorenz-Mie Theory(GLMT). Furthermore, the radiation torque corresponding to each Debye mode p is mainly analyzed. Results show that when incident beam is linearly polarized, all scattering processes for p in 1-5 can produce a transverse torque while the directions of torque are different. When the beam is circularly polarized, the torques for p in 1 and 0 are much larger than that for p in 1-4, and the direction of torque for p in 0 is opposite with that for other mode p.
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Key words:
- radiation torque/
- Debye series/
- Gaussian beam/
- optical tweezer/
- angular momentum
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[1] ASHKIN A,DZIEDZIC J M. Optical trapping and manipulation of viruses and bacteria[J].Science,1987,235:1517-1520. [2] FRIESE M E J,NIEMINEN T A,HECKENBERG N R,et al.. Optical alignment and spinning of laser-trapped microscopic particles[J].Nature,1998,394:348-350. [3] STEWART A M. Angular momentum of the electromagnetic field:the plane wave paradox resolved[J].Eur. J. Phys.,2005,26:635-641. [4] CHANG S,LEE S S. Optical torque exerted on a homogeneous sphere levitated in the circularly polarized fundamental-mode laser beam[J].J. Opt. Soc. Am. B,1985,2:1853-1860. [5] GAUTHIER R. C. Trapping model for the low index ring shaped micro-object in a focused lowest order Gaussian beam profile[J].J. Opt. Soc. Am. B,1997,14 (4):782-789. [6] ROHRBACH A,STELZER E H K. Optical trapping of dielectric particles in arbitrary fields[J].J. Opt. Soc. Am. A,2001,18:839-853. [7] POLAERT H,GREHAN G,GOUESBET G. Forces and torques exerted on a multilayered spherical particle by a focused Gaussian beam[J].Opt. Commun.,1998,155:169-179. [8] GOUESBET G,MAHEU B,GREHAN G. Light scattering from a sphere arbitrarily located in a Gaussian beam, using a Bromwich formulation[J].J. Opt. Soc. Am. A,1988,5:1427-1443. [9] DEBIJE P. Das elektromagnetische feld um einen zylinder und die theorie des regenbogens[J].Phys. Z.,1908,9:775-778 . [10] HOVENAC E A,LOCK J A. Assessing the contributions of surface waves and complex rays to far-field scattering by use of the Debye series[J].J. Opt. Soc. Am. A,1992,9:781-795. [11] LOCK J A,JAMISON J M,LIN C Y. Rainbow scattering by a coated sphere[J].Appl. Opt.,1994,33:4677-4690. [12] LI R,HAN X,JIANG H,et al.. Debye series of light scattering by a multi-layered sphere[J].Appl. Opt.,2006,45:1260-1270. [13] LI R,HAN X,JIANG H,et al.. Debye series of normally incident plane wave scattering by an infinite multi-layered cylinder[J].Appl. Opt.,2006,45:6255-6262. [14] LOCK J A,ADLER C L. Debye-series analysis of the first-order rainbow produced in scattering of a diagonally incident plane wave by a circular cylinder[J].J. Opt. Soc. Am. A,1997,14:1316-1328. [15] LI R,HAN X,REN K F. Generalized Debye series expansion of electromagnetic plane wave scattering by an infinite multilayered cylinder at oblique incidence[J].Phys. Rev. E,2009,79:036602. [16] LOCK J A. Debye series analysis of scattering of a plane wave by a spherical Bragg grating[J].Appl. Opt.,2005,44:5594-5603. [17] LI R,HAN X,REN K F. Debye series analysis of radiation pressure force exerted on a spherical particle[J].SPIE,2009,7507:750708. [18] LI R,HAN X,REN K. F. Debye series analysis of radiation pressure force exerted on a multilayered sphere[J].Appl. Opt.,2010,49:955-963. [19] XU F,LOCK J A,GOUESBET G,et al.. Radiation torque exerted on a spheroid:analytical solution[J].Phys. Rev. A.,2008,78:013843.
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