Shaping of a reflective microjet via the addition of a metal mask onto a dielectric scatterer

Abstract

The method of shaping a reflective microjet (MJ) via the addition of a metal mask onto a dielectric scatterer is proposed. The study focuses on the effects of size, shape of metal mask, and shape of scatterer on the performance of the MJ. The results show that the mask size is a vital factor in tailoring the characteristic parameters of the MJ, especially the focal length (FL). With a properly designed mask size, the FL can increase by 0.51λ, as much as 4 times the FL of a MJ generated without a metal mask. The mask size dependence of MJ parameters is related to the change of number and position of phase singularity in Poynting vector distribution. And the shapes of the mask and scatterer only slightly affect the optimal mask size at which the FL maximizes. In addition, the MJ generated by the presently proposed scattering system can work in the frequency range of 0.1 THz–1.4 THz. The effect of frequency on MJ properties is related to the dispensation and absorption of material. The proposed method can be used to effectively tailor the FL of the reflective MJ to meet the requirements set by various applications.