Near-infrared thermal modulation zoom super-structure lens based on phase change material Sb2S3

Abstract

The invention discloses a near-infrared thermal modulation zoom super-structure lens based on a phase change material Sb2S3. The near-infrared thermal modulation zoom super-structure lens comprises an elliptical Si nano-column on the bottom layer and an elliptical Sb2S3 nano-column on the upper layer, a filling material SiO2 is deposited on the periphery of the elliptical Si nano-column, and an ITO layer is deposited between the filling material SiO2 and the elliptical Sb2S3 nano-column. According to the invention, the phase-change material Sb2S3 is used for thermally modulating a zoom super-structure lens. In the near-infrared region, a real part refractive index change exists between the amorphous state and the crystalline state of the Sb2S3, and the loss in the two states is very low. By switching the Sb2S3 between the two states, the variable-focal-length double-layer super-structure lens is realized. The maximum full width at half maximum of each focus of the lens is close to the diffraction limit. The focusing efficiency of the two focuses can reach more than 50%. The super-structure lens has the advantages of thermal control, good imaging effect and the like, and has a huge application potential in the fields of multifunctional devices, biomedicine, communication, imaging and the like.

Description

technical field [0001] The invention relates to the technical field of metalens, in particular to a lens based on phase change material Sb 2 S 3 Near-infrared thermally modulated zoom metalens. Background technique [0002] As an emerging technology based on metasurfaces, metalenses are not only small in size, but also have an unprecedented ability to control the focusing of incident light wavefronts, providing a new platform for the integration of optical lenses. With the rapid development of metalens research, the limitations of metalens in practical applications have gradually emerged, such as limited working bandwidth and fixed focal length. Therefore, many studies are devoted to tunable metalenses. For tunable metalens, zoom metalens is one of the most important components. Zoom metalenses enable the miniaturization of conventional lenses for applications such as alarms, laser processing, virtual imaging, and detection. In recent years, zooming strategies such as m...

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Problems solved by technology

But this way will reduce the focusing efficiency of the focus. Vanadium dioxide (VO 2 ), another widely used phase change material, which can switch the phase change between dielectric state and metallic titanium

Vanadium dioxide has been used to switch between transmissive and reflective focusing, but the focal length of the metalens cannot be changed in both states

In addition, vanadium dioxide requires constant thermal energy to maintain the metallic state, which also limits its application.

The above-mentioned phase change materials have limitations when used as a more practical transmissive zoom metalens

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