Tightly focusing metalens based on the high order Bessel function

• DOI: 10.1364/ol.517256
• Publication Date: 2024-04-10T16:00:06Z
• Authors: Zhaojin Guo; Xuanguang Wu; Liang Zhou; Yanke Li; Bingyan Wei; Dandan Wen; Peng Li; Jianlin Zhao; Sheng Liu
• Keywords: 01 natural sciences; 0104 chemical sciences

We propose a new, to the best of our knowledge, type metalens which phase profile is extracted from higher-order Bessel function. A light beam passing through this would focus along circular trajectory and produces tightly focusing field. Utilizing binarization, we provide method design geometric-phase dielectric metasurface both for polarization modulations. demonstrate two metalenses circularly radially polarized output beams at 633 nm, with measured 0.737λ 0.616λ focal spots, respectively. Theoretically, it can realize super-diffraction-limit spot (0.38λ). This work extend way realizing focused optical devices.