FDTD法模拟手征介质柱的波传播和洛伦兹力密度

Wave Propagation and the Lorentz Force Density of a Chiral Column Based on the FDTD Method

  • 摘要: 基于辅助差分方程时域有限差分法,模拟了色散手征介质柱的电磁场和洛伦兹力密度分布。从本构关系出发,给出了手征介质中频域电、磁极化强度与感应电、磁极化强度和耦合电、磁极化强度之间的关系;并给出了波方程和电场的迭代公式。推导了手征介质中含束缚电荷、电流和束缚磁荷、磁流密度的时均洛伦兹力密度表达式。与相关文献结果进行了对比,验证了辅助差分方程时域有限差分法和洛伦兹力密度方法的正确性。仿真了增益手征介质柱的场和光力分布情况,讨论了电磁流和电磁荷对洛伦兹力密度的贡献,为手征介质在光镊和手征参数测量等工程应用提供了理论指导。

     

    Abstract: Based on the auxiliary differential equation (ADE) finite-difference time-domain (FDTD) method, distributions of electromagnetic fields and Lorentz force densities in a dispersive chiral column are simulated. Firstly, relationships between electromagnetic polarization densities and induced electromagnetic polarization densities, as well as coupled electromagnetic polarization densities of chiral media, are presented based on the constitutive relations. Wave equations and recurrence formula of electric are given. Secondly, the Lorentz force density in chiral media containing bound electric charge and electric current densities, as well as bound magnetic charge and magnetic current densities, is derived. Then, we verify the correctness of the ADE-FDTD method and the Lorentz force density method by comparing with literature's results. Finally, distributions of fields and optical forces for an active chiral cylinder are simulated. The contribution of electromagnetic current and electromagnetic charge densities to the Lorentz force density is discussed. The work in this paper provides some theoretical guidance for chiral media's potential engineering applications in optical tweezers and measurement of chiral parameter.

     

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