Magnetic field controlled electromagnetic wave scattering from a cluster of gyrotropic core–dielectric shell cylinders

In view of tunable and nonreciprocal terahertz devices, we study electromagnetic wave scattering from a cluster of gyroelectric core--dielectric shell cylinders. In particular, we consider InSb core-Ge shell cylinders under magnetic fields less than 2.4 T. We expand the electromagnetic fields in terms of the vector cylindrical wave functions and relate the expansion of the scattered field to that of the incident field. We show that a cluster exhibits distinct scattering cross sections upon illumination by oppositely directed waves. The excitation of nondipolar modes in a cluster even as simple as a dimer enables magnetic field switching between highly forward and highly backward scattering patterns. Moreover, nearly complete simultaneous suppression of both forward and backward scattering is feasible. A finite array of cylinders may serve as a magnetic field controlled terahertz beam steerer.