Affiliation:
1. Fudan University
2. Berxel Photonics Co. Ltd.
3. Chinese University of Hong Kong
4. Peng Cheng Laboratory
Abstract
Bessel beam arrays are highly attractive due to non-diffraction properties, parallel processing, and large capacity capabilities. However, conventional approaches of generating Bessel beams, such as spatial light modulators, axicons, and diffraction optical elements, suffer from various limitations of system complexity and bulkiness, low uniformity, and limited numerical aperture (NA). The limited NA imposes constraints on achieving minimal full width at half maximum (FWHM) of the Bessel beam, ultimately compromising the resolution of the beam. In this study, we demonstrate a method for generating Bessel beam arrays with regular and random patterns via an ultra-compact metasurface. This approach integrates the phase profile of an optimized beam splitter with a meta-axicon. The Bessel beam arrays exhibit subwavelength dimensions of FWHM (590 nm, ∼0.9λ) and relatively high uniformity of 90% for NA=0.2 and 69% for NA=0.4. Furthermore, the method achieves effective suppression of background noise and zeroth-order intensity compared to methods based on Dammann grating (DG) based metasurfaces. The proposed method highlights potential applications of Bessel beam arrays in various fields, such as laser machining, optical communication, and biomedical imaging.
Funder
Hetao Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Program
Shenzhen Science and Technology Innovation Program
Guangdong Major Talent Introduction Project