Control of axial position of terajet generated in reflection mode

A theoretical study was performed on control of axial position of a terajet (TJ) by polarization state of incident plane wave. The TJ is generated in a reflection mode realized by putting a cuboid scatterer onto a reflection screen. The study shows that the polarization affects mainly transversal electric field profile of TJ as the scattering system has a higher symmetric structure, while affects more the focal length (FL) of TJ as the system has a lower symmetric structure. Further study focuses on the polarization effect of the FL of the TJ generated by a scattering system with a lower symmetry, and asymmetries caused by geometries of scatterer and reflection screen and their relative position are considered. The results show that the effect is closely related to the asymmetric extent of scatterer system and both have a non-monotonic relationship. The polarization can induce FL change by nine times. The effect caused by geometric asymmetry of scatterer or reflection screen is stronger than that by the asymmetry of their relative position. The introduction of reflection screen increases complexity of interference of scattered waves and hence results in some interesting features of FL polarization effect, such as non-monotonic asymmetry dependence, absence of the effect for some specific asymmetrical structures and threshold polarization angle effect on characteristic parameters of TJ. It is included that the FL of the TJ generated by an asymmetric scatterer structure in reflection mode can be effectively controlled by polarization state.