Calculation of radiation forces exerted on a uniaxial anisotropic sphere by an off-axis incident Gaussian beam

Abstract

Using the theory of electromagnetic scattering of a uniaxial anisotropic sphere, we derive the analytical expressions of the radiation forces exerted on a uniaxial anisotropic sphere by an off-axis incident Gaussian beam. The beam's propagation direction is parallel to the primary optical axis of the anisotropic sphere. The effects of the permittivity tensor elements ε(t) and ε(z) on the axial radiation forces are numerically analyzed in detail. The two transverse components of radiation forces exerted on a uniaxial anisotropic sphere, which is distinct from that exerted on an isotropic sphere due to the two eigen waves in the uniaxial anisotropic sphere, are numerically studied as well. The characteristics of the axial and transverse radiation forces are discussed for different radii of the sphere, beam waist width, and distances from the sphere center to the beam center of an off-axis Gaussian beam. The theoretical predictions of radiation forces exerted on a uniaxial anisotropic sphere are hoped to provide effective ways to achieve the improvement of optical tweezers as well as the capture, suspension, and high-precision delivery of anisotropic particles.

Analysis of the radiation force of a Laguerre Gaussian vortex beam exerted on an uniaxial anisotropic sphere

“…Fig. 4 [53]. The result agrees well with the reference, which verified the accuracy of our theory and code.…”

“…In addition, with the increasing applications of anisotropic material, namely, silicon dioxide, yttrium iron garnet(YIG) and iron oxide, in integrated optics, microwave and millimeter technology and microstrip, investigations about the optical manipulation on anisotropic material has gained growing attention [47,48]. Wu's group has devoted to the electromagnetic field of uniaxial anisotropic sphere [49,50], coated sphere [51], bispheres [52] and RF on uniaxial anisotropic sphere [53] induced by GB, scattering of uniaxial anisotropic sphere by zero order Bessel beam [54] etc. Geng investigated the scattering of uniaxial [55], plasma and ferrite anisotropic sphere and coated spheres [56][57][58].…”

On the electromagnetic scattering of arbitrary shaped beams by arbitrary shaped particles: A review

“…Zhang and Liao dealt with scattering of Gaussian beam by a spherical particle having a spheroidal inclusion [115]. Li et al were concerned with the calculation of radiation forces exerted on a uniaxial anisotropic sphere by an offaxis incident Gaussian beam [116]. Wu et al dealt with off-axis Gaussian beam scattering by an anisotropic coated sphere [117].…”

List of problems for future research in generalized Lorenz–Mie theories and related topics, review and prospectus [Invited]

“…This also includes (i) a host sphere with an eccentric spherical inclusion, called an "eccentric sphere" for short [37][38][39], (ii) a multilayer sphere [40][41][42][43], (iii) the infinite cylinder [44,45], with dielectric coating [46], multilayered [47,48], or illuminated by two Gaussian beams [49], and (iv) a bisphere [50] that may be viewed as a very simple case of an assembly of spheres [51], and an aggregate of coated spheres [52], and finally (v) non-isotropic particles [53][54][55][56].…”