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Breaking the Diffraction Limit with Radially Polarized Light Based on Dielectric Metalenses
Author(s) -
Zuo Ruizhi,
Liu Wenwei,
Cheng Hua,
Chen Shuqi,
Tian Jianguo
Publication year - 2018
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201800795
Subject(s) - optics , numerical aperture , diffraction , dielectric , materials science , aperture (computer memory) , polarization (electrochemistry) , focus (optics) , focal length , radius , focal point , wavelength , physics , optoelectronics , lens (geology) , cardinal point , computer science , chemistry , computer security , acoustics
Dielectric metalenses with high efficiency and compact size have been widely investigated recently, but still suffer from Abbe diffraction limit. Herein, with linear polarization incidence, a dielectric metalens is demonstrated to efficiently generate and focus radially polarized light simultaneously. Two novel methods are proposed to achieve super‐resolution. First, a circular high‐pass aperture is utilized to enhance the longitudinal field component in the vicinity of focus with the focal spot size of 0.138λ 2 , much smaller than the theoretical limit of 0.212λ 2 . The key parameters that impact the focusing size are explored in detail, such as radius of the circular aperture and numerical aperture of the metalens. Second, an extra phase distribution is added on the metalens to filter the transversely polarized component, which leads to a focal spot size of 0.144λ 2 . The approach provides a wide platform for sub‐resolution focusing and imaging, which offers the capability of subdiffraction techniques for microscopy systems and information processing with extensive channels.