Polarization multiplexing holographic imaging method based on transmission type all-medium metasurface

Abstract

The invention belongs to the technical field of micro-nano optics, polarization optics and optical holographic, and discloses a polarization multiplexing holographic imaging method based on a transmission type all-medium metasurface. A response main wavelength <lambda> is determined; geometric parameters of a unit structure are determined; a GS phase recovery algorithm is adopted to obtain phase distribution of the unit structure responding to the main wavelength; the pixel point of each element is expanded into a 2*2 array by adopting a Dammann grating method, and the obtained each pixel unitcomprises information responding to horizontal polarized light and information responding to vertical polarized light; and a synthesized silicon nano-antenna array is irradiated by horizontal polarized light and vertical polarized light with the wavelength of <lambda>, and different holographic images are reconstructed. According to the method, phase modulation of 0-2 <pi> can be realized only bychanging the size of the short axis of the silicon nano-antenna, and an embossment phase modulation structure of any step number can be realized equivalently; and a simple process, high processing error tolerance and quite high stability and reliability are achieved.

Description

technical field [0001] The invention belongs to the technical fields of micro-nano optics, polarization optics and optical holography, and in particular relates to a polarization multiplexing holographic imaging method based on a transmissive all-dielectric metasurface. Background technique [0002] At present, the existing technologies commonly used in the industry are as follows: Polarization multiplexing holographic elements are very sensitive to the polarization characteristics of incident light, and can reproduce different holographic patterns by different polarization directions of incident light fields, so as to realize various applications, such as image processing, polarization detection, information storage, optical encryption etc. The traditional fabrication of polarization holographic elements is mainly based on the birefringence characteristics of natural materials or the effective birefringence characteristics achieved by etching sub-wavelength periodic struct...

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Problems solved by technology

[0004] (1) The use of birefringent crystals can be used to prepare polarized optical devices, but it is limited by the type and size of the crystals

[0005] (2) Artificial materials with subwavelength structures can provide a selective method to enhance and control birefringence properties, but strong anisotropy requires high aspect ratios, and special etching and resolution requirements increase the Processing difficulty

[0006] (3) The traditional polarization holographic device has a narrow response bandwidth, and the phase function and diffraction efficiency will change when the wavelength of the incident light changes

[0007] (4) Traditional polarization holographic devices are expensive, complex in process, large in size and heavy in weight, not suitable for optical integration, and unable to meet the development trend of future photonic devices

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