A far-field superdiffraction focusing lens based on a dielectric-metal strip structure array

Abstract

The invention provides a far-field sub-diffraction limited focusing lens based on a medium-metal bar-type structure array. The far-field sub-diffraction limited focusing lens comprises a base, a medium bar-type structure unit and a metal bar-type structure unit, wherein the medium bar-type structure with multi-value phase regulation capability and the metal bar-type structure with two-value vibration amplitude regulation capability are adopted, the phase of emergent lights is determined by the thickness of the medium bar-type structure, and the vibration amplitude of the emergent lights is determined by the thickness of the metal bar-type structure; by virtue of changing the thickness of medium bars and metal bars, multi-value phase regulation and two-value vibration amplitude are realized; by virtue of a spatial planar array formed by metal bar structure units and metal bar structure units, lens transmission function vibration amplitude-phase spatial distribution needed for far-field sub-diffraction limited focusing is realized, so that a far-field sub-diffraction limited focusing function capable of breaking a diffraction limit is realized, far-field sub-diffraction limited focusing spots are reduced, the focusing efficiency is improved, sidelobes are inhibited and the field range is enlarged.

Description

technical field [0001] The invention belongs to the field of light focusing and light imaging, and in particular relates to a multi-value phase-binary amplitude control far-field super-diffraction focusing lens. Background technique [0002] For conventional microlenses, although various phase structures are used, they still fail to break through the diffraction limit. For far-field superdiffraction focusing devices, binary amplitude control or quasi-continuous amplitude control is usually used, which often cannot achieve good focusing performance. The low focusing efficiency and excessive sidelobe intensity severely limit the development of superdiffraction devices. Far-field super-diffraction focusing is the result of precise interference of light waves. Therefore, it is very necessary to introduce phase control into the device transmittance function in the design and implementation of super-diffraction devices. The sub-wavelength structure based on multi-valued phase-bin...

AI Technical Summary

Problems solved by technology

For far-field super-diffraction focusing devices, binary amplitude control or quasi-continuous amplitude control is usually used, which often cannot achieve good focusing performance. The low focusing efficiency and excessive side lobe strength severely limit the development of super-diffraction devices.

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