Transmission-type metal metamaterial beam polarization distribution transform device

Abstract

The invention provides a transmission-type metal metamaterial beam polarization distribution transform device. The device comprises a dielectric substrate, a metal metamaterial layer which is arranged on the dielectric substrate and comprises a metal particle periodic array, and a dielectric coating layer which is arranged on the metal metamaterial layer. Each metal particle in the metal particle periodic array at least comprises one pair of parallel smooth planar sidewalls used for forming Fabry-Perot resonant cavities between adjacent metal particles in the direction perpendicular to the smooth planar sidewalls. The metal metamaterial layer comprises the metal particle periodic array with an azimuth angle. The polarization rotation angle of incident light is adjusted by varying the azimuth angle. Alternatively, the metal metamaterial layer comprises a number of metal particle periodic arrays with different azimuth angles. The spatial polarization distribution of incident light is changed by changing the spatial arrangement of a number of metal particle periodic arrays. The device has the characteristics of wide band adaptation, high work efficiency, simple structure and easy preparation.

Description

technical field [0001] The invention relates to the field of optical devices, in particular to a transmissive metal metamaterial beam polarization distribution conversion device. Background technique [0002] Compared with traditional optical devices, metamaterial optical devices have attracted widespread attention due to their outstanding advantages such as flexible design of device functions, sub-wavelength effective device thickness, and easy-to-integrate planar device structure. The scheme of using optical metamaterials to transform the polarization distribution of beams has also been reported frequently. According to the types of functional unit materials, the existing metamaterial beam polarization control devices can be divided into two types: dielectric metamaterial polarization control devices and metal metamaterial polarization control devices. Among them, dielectric metamaterials mostly use the Mie resonance in the dielectric particles to adjust the polarization ...

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Problems solved by technology

[0003] The beam polarization control device based on dielectric metamaterials has extremely low absorption loss when the wavelength is larger than its absorption edge, so the device shows extremely high work efficiency; Exhibits strong absorption and thus cannot work efficiently

For example, the most common dielectric metamaterial working medium silicon, its working band is limited to more than 1.1 microns, and high-efficiency polarization control cannot be achieved in the visible light band.

Although some devices using wide-bandgap dielectric materials such as titanium oxide can work in the visible light band, their structural aspect ratio is too large, making it extremely difficult to prepare and costly, making it difficult to popularize

[0004] Most of the early metal metamaterial beam polarization control devices are composed of single-layer ultra-thin metal nanostructures. Such metamaterial beam polarization control devices based on single-layer ultra-thin metal nanostructures cannot effectively suppress the reflection and absorption of metal structures, so its efficiency is very low

Multilayer metal nanostructures can generate electrical resonance and magnetic resonance at the same time, which can partially suppress reflection and absorption, and its efficiency is greatly improved compared with the phase control devices of early single-layer ultra-thin metal nanostructures, but the current highest efficiency is still Below 50%, and the preparation process of multilayer metal nanostructure is complex and costly

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