Radiation torque on a sphere caused by a circularly-polarized electromagnetic wave

Marston, Philip L.; Crichton, James H.

doi:10.1103/physreva.30.2508

Cited by 135 publications

(98 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although several reports [22, 24-26, 28, 34, 44] realize the need of energy absorption by the object in order that it experiences a torque, no explicit demonstration exists of the role played in this effect by the variation of incident spin and orbital angular momenta, even though they are calculated in some cases after scattering [8,9,34,35]. Moreover, studies based on the static approximation [27-30, 32, 53], only deal with the so-called intrinsic torque which, as as shown below cannot account for the angular momentum transfer nor can describe the resulting torque experienced by the object through energy absorption.…”

Section: Introductionmentioning

confidence: 99%

“…Observations are more difficult to control and to quantitatively interpret with existing models. With few exceptions [34,36], most experimental [27,28] and theoretical [29][30][31][32][33][34]53] studies employ a static formulation, (perhaps following the path of pioneering work [21]), which was shown [37] to be incomplete and not compatible with energy and angular momentum conservation. Only for extremely small (i.e.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Optical torque: Electromagnetic spin and orbital-angular-momentum conservation laws and their significance

Nieto‐Vesperinas

2015

Phys. Rev. A

View full text Add to dashboard Cite

The physics involved in the fundamental conservation equations of the spin and orbital angular momenta leads to new laws and phenomena that are disclosed here. To this end, we analyse the scattering of an electromagnetic wavefield by the canonical system constituted by a small particle, which is assumed dipolar in the wide sense. Specifically, under quite general conditions these laws lead to understanding the contribution and weight of each of those angular momenta to the electromagnetic torque exerted by the field on the object, which is shown to consist of an extinction and a scattering, or recoil, part. This leads to an interpretation of its effect different to that taken up till now by many theoretical and experimental works, and implies that a part of the recoil torque cancels the usually called intrinsic torque which was often considered responsible of the particle spinning. In addition, we obtain the contribution of the spatial structure of the wave to this torque, unknown to this date, showing its effect in the orbiting of the object, and demonstrating that it often leads to a negative torque on a single particle, i.e. opposite to the incident helicity, producing an orbital motion contrary to its spinning. Furthermore, we establish a decomposition of the electromagnetic torque into conservative and non-conservative components in which the helicity and the spin angular momentum play a role analogous to the energy and its flux for electromagnetic forces. These phenomena are illustrated with examples of beams, also showing the difficulties of some paraxial formulations whose fields do not hold the transversality condition.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optical torque: Electromagnetic spin and orbital-angular-momentum conservation laws and their significance

Nieto‐Vesperinas

2015

Phys. Rev. A

View full text Add to dashboard Cite

show abstract

“…Some of the formulae used here are included in Appendix A. In particular, we recall that their divergence, involved in Equation (5), is related to (scalar) spherical harmonics, so that, by using the expansion (8) and the orthogonality of the spherical harmonics, we express the integral in Equation (5) in terms of spherical harmonics. Then we recall that the gradient of the latter functions is related to vector spherical harmonics, so we recover these functions in the rhs of Equation (5).…”

Section: Coulomb Interactionmentioning

confidence: 99%

“…The main result of this investigation is a selective absorption of light by small particles, for some frequencies which, thereafter, were associated with the frequencies of the "spherical" plasmons [2][3][4]. Recently, the subject enjoys a great deal of interest, in connection with plasmons and polaritons in structures with restricted geometry, their role in the diffraction of the electromagnetic wave and a possible enhancement of the scattered field [5][6][7][8][9][10][11][12][13][14][15]. The physics underlying such phenomena is entangled in the original Mie's results with the mathematical complexity of the problem.…”

Section: Introductionmentioning

confidence: 99%

Plasmons and Diffraction of an Electromagnetic Plane Wave by a Metallic Sphere

Apostoł¹,

Vaman²

2009

PIER

View full text Add to dashboard Cite

Abstract-The diffraction of a plane electromagnetic wave by an ideal metallic sphere (Mie's theory) is investigated by a new method. The method represents the charge disturbances (polarization) by a displacement field in the positions of the mobile charges (electrons) and uses the equation of motion for the polarization together with the electromagnetic potentials. We employ a special set of orthogonal functions, which are combinations of spherical Bessel functions and vector spherical harmonics. This way, we obtain coupled integral equations for the displacement field, which we solve. In the nonretarded limit (Coulomb interaction) we get the branch of "spherical" (surface) plasmons at frequencies ω = ω p l/(2l + 1), where ω p is the (bulk) plasma frequency and l = 1, 2, . . .. When retardation is included, for an incident plane wave, we compute the field inside and outside the sphere (the scattered field), the corresponding energy stored by these fields, Poynting vector and scattering cross-section. The results agree with the so-called theory of "effective medium permittivity", although we do not start the calculations with the dielectric function. In turn, we recover in our results the well-known dielectric function of metals. We have checked the continuity of the tangential components of the electric field and continuity of the normal component of the electric displacement at the sphere surface, as well as the conservation of the energy flow and re-derived the "optical theorem". In the limit of small radii (in comparison with the electromagnetic wavelength) the sphere exhibits a series of resonant absorptions at frequencies close to the plasmon frequencies given above. For large radii these resonances disappear.Corresponding author: M. Apostol (apoma@theory.nipne.ro). 98Apostol and Vaman

show abstract

“…Both x and y linearly polarized beams are described, so two such beams 90°o ut of phase may be superposed to produce a circularly polarized beam, which is necessary for the production of an optical torque on a particle. 35,36 I expect to address the calculation of optical torques by use of the GLMT in a future paper. In Section 3, I briefly summarize the formulas for both a freely diffracting focused Gaussian beam and a plane wave truncated and focused by a high-NA lens and then either reflected or refracted by a flat interface located before the beam's focal waist.…”

Section: Introductionmentioning

confidence: 99%

Calculation of the radiation trapping force for laser tweezers by use of generalized Lorenz-Mie theory I Localized model description of an on-axis tightly focused laser beam with spherical aberration

Lock¹

2004

Appl. Opt.

View full text Add to dashboard Cite

Radiation torque on a sphere caused by a circularly-polarized electromagnetic wave

Cited by 135 publications

References 26 publications

Optical torque: Electromagnetic spin and orbital-angular-momentum conservation laws and their significance

Optical torque: Electromagnetic spin and orbital-angular-momentum conservation laws and their significance

Plasmons and Diffraction of an Electromagnetic Plane Wave by a Metallic Sphere

Calculation of the radiation trapping force for laser tweezers by use of generalized Lorenz-Mie theory I Localized model description of an on-axis tightly focused laser beam with spherical aberration

Contact Info

Product

Resources

About