Rohrbach A, Stelzer E H
European Molecular Biology Laboratory, Heidelberg, Germany.
J Opt Soc Am A Opt Image Sci Vis. 2001 Apr;18(4):839-53. doi: 10.1364/josaa.18.000839.
We present a new method to calculate trapping forces of dielectric particles with diameters D < or = lambda in arbitrary electromagnetic, time-invariant fields. The two components of the optical force, the gradient force and the scattering force, are determined separately. Both the arbitrary incident field and the scatterer are represented by plane-wave spectra. The scattering force is determined by means of the momentum transfer in either single- or double-scattering processes. Therefore the second-order Born series is evaluated and solved in the frequency domain by Ewald constructions. Numerical results of our two-force-component approach and an established calculation method are compared and show satisfying agreement. Our procedure is applied to investigate axial trapping by focused waves experiencing effects of aperture illumination and refractive-index mismatch.
我们提出了一种新方法，用于计算直径D≤λ的电介质颗粒在任意电磁时不变场中的俘获力。分别确定了光力的两个分量，即梯度力和散射力。任意入射场和散射体均由平面波谱表示。散射力通过单散射或双散射过程中的动量转移来确定。因此，通过埃瓦尔德构造在频域中评估并求解二阶玻恩级数。比较了我们的双力分量方法与既定计算方法的数值结果，二者吻合良好。我们的方法被应用于研究聚焦波在经历孔径照明和折射率失配效应时的轴向俘获。
