Wave propagation and Lorentz force density in gain chiral structures

The electromagnetic coupling and mechanical interaction between a plane wave and dispersive gain chiral structures are investigated using the Auxiliary Differential Equation Finite Difference Time Domain (ADE-FDTD) method. Utilizing the constitutive relations containing frequency-dependent Lorentzian models and a Condon model, the wave equations and time-averaged Lorentz force density for the magneto-electric coupling chiral media are presented. Numerical results show that the cross-polarized transmission coefficient is larger than the co-polarized transmission coefficient for a gain chiral slab with certain thickness. The gradient force engendered by bound currents of the cross-polarized waves in chiral media is larger than the scattering force to pull the slab towards the incident source. The complicated optical pulling or pushing force density among slabs, which is illuminated by a normally incident plane wave, containing chiral materials with different medium parameters is achieved. (C) 2016 Optical Society of America