提出一种轴棱锥-透镜-轴棱锥的相位透镜组结构,对该结构进行理论分析和模拟仿真计算,并采用快速三维打印技术制备的轴棱锥进行实验验证,获得无衍射长度接近1000 mm的太赫兹贝塞尔波束。该波束的无衍射区域不再紧贴轴棱锥,而是具有约100 mm的投送距离。该研究结果可促进太赫兹贝塞尔波束在大景深成像方面的应用。

This study aims to propose a structure of axicon-lens-axicon phase lens group. The structure is simulated and analyzed theoretically. The experimental verification is conducted using the rapid 3D printing technology to prepare an axonal pyramid, and a terahertz Bessel beam with 1000 mm diffraction-free length is generated. The results indicate that the diffraction-free region of such a beam is no longer proximal to the axial pyramid, but has a 100 mm distance from the final axicon. The findings in this study are helpful for the application of a terahertz Bessel beam in the field of large depth of field imaging.