Production of THz pseudo-Bessel beams with uniform axial intensity using irregular binary axicons

To produce THz pseudo-Bessel beam with uniform axial intensity distribution within a desired range, an irregular binary axicon (IBA) is proposed and designed in the authors´ paper. Unlike a regular binary axicon (RBA) having the same prism angle, the IBA consists of concentric prism-like grooves with the different prism angles. It can be obtained from the RBA by an optimisation design. Comparison results demonstrate that within a specified region the on-axis intensity distributions of the pseudo-Bessel beams generated by the designed IBAs are much smoother than those produced by the RBAs.