AUTHOR=Sun Changwei , Wang Quansen , Liang Jing , Wang Wencong , Liu Dongmei , Chen Zhenhua , Gu Min 

TITLE=Theoretical realization of tunable hollow beams using a periodical ring structure with a complex phase

JOURNAL=Frontiers in Physics

VOLUME=Volume 12 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2024.1383835

DOI=10.3389/fphy.2024.1383835

ISSN=2296-424X

ABSTRACT=We theoretically propose a novel diffraction optical element to generate tunable hollow beams. This element is composed of periodic concentric rings. The phase of each ring is periodically distributed between -𝜋𝜋 and 𝜋𝜋 and satisfies a complex variable function. By tuning the parameters of the structure, we can flexibly manipulate the size and length of the hollow beam. The length of the beam can be increased from 98𝜆𝜆 to 248𝜆𝜆, and the full width at half maximum varies from 0.43𝜆𝜆 to 0.61𝜆𝜆. Moreover, the light intensity and side lobe of the hollow beam can also be regulated using the designed diffraction optical element. The potential applications of this highly tunable hollow beam include optical nanomanipulation, microscopic imaging, and nanolithography.