Generation of pseudo-Bessel beams at THz frequencies by use of binary axicons.

In order to miniaturize and integrate conveniently in THz quasi-optical systems, binary axicons, based on binary optical ideas, are introduced in our paper and designed for generating pseudo-Bessel beams at THz frequencies. The designed binary axicons are easier to fabricate than holographic axicons, more compact and thus less lossy in the material when compared with classical cone axicons. To calculate the electromagnetic fields diffracted by binary axicons precisely, a two-dimension finite-difference time-domain (2-D FDTD) method in conjunction with Stratton- Chu formulas are employed in this paper. Applying this method, the properties of pseudo-Bessel beams produced by binary axicons are analyzed, and a brief summary is given in the end.