Generation of achromatic auto-focusing Airy beam for visible light by an all-dielectric metasurface
Song Zhang, Pengcheng Huo, Yilin Wang, Moxin Li, Cheng Zhang, Ting Xu
Abstract
The focusing performance of optical beams has always played an important role in various applications such as imaging, displaying, and sensing. In contrast to a traditional focused beam with gradually increasing light intensity, an auto-focusing Airy beam exhibits an abrupt way of focusing light energy. However, owning to the chromatic dispersion of light, the previously demonstrated auto-focusing Airy beam always suffers from chromatic aberration. Here, we show that with judicious dispersion engineering of its constituent nanostructures, a metasurface can generate auto-focusing Airy beam without chromatism for the visible light. In experimental demonstration, we implement a dielectric metasurface composed of TiO2 nanopillars that generates an achromatic auto-focusing Airy beam with diffraction-limited performance covering the wavelength range from 450 to 600 nm. This study paves the way toward efficient achromatic auto-focusing Airy beam generation based on flat optical components, enabling diverse potential applications including biomedical imaging, light-sheet microscopy, and particle manipulation.