A preparation method of an all-dielectric metalens that transforms Gaussian light into top-hat light

Abstract

The invention discloses an all-dielectric hyperlens that transforms Gaussian light into a top-hat light and a preparation method thereof, and belongs to the field of laser beam shaping. The all-dielectric hyperlens includes: a dielectric substrate layer and a metasurface structure; the metasurface structure is located on the dielectric substrate layer On one side of the surface, there are multiple metasurface columnar structural units arranged in a periodic array of tetragonal lattices, and the height of each metasurface columnar structural unit is the same. Based on the Gaussian light, the amplitude distribution of the target flat-top optical field intensity, and the electric field intensity distribution of the input and output surfaces of the all-dielectric metalens, the metalens phase is optimally designed, and the metalens is designed and prepared according to the phase after the optimized design. The metasurface structure greatly reduces the volume of the beam shaping device, and the thickness of the device can be reduced to the order of hundreds of microns, without adding other components, simplifying the beam shaping device, and reducing the assembly accuracy requirements. The metalens has the advantage of high phase regulation accuracy and can Realize continuous phase regulation.

Description

technical field [0001] The invention belongs to the field of laser beam shaping, and more specifically relates to an all-dielectric superlens for shaping Gaussian light into flat-hat light and a preparation method thereof. Background technique [0002] The energy of the laser beam generally obeys the Gaussian distribution, and the non-uniformity of the energy will cause the local temperature to rise and destroy the material. In many laser application fields, this non-uniformity will limit its application. Therefore, it is necessary to shape the Gaussian beam. A top-hat beam with good uniformity is obtained. Flat-top beam refers to a laser beam with uniform energy density in the cross-section of the beam transmission direction. Due to its uniform energy distribution, it plays an important role in the fields of laser welding, laser drilling, laser ablation, laser medical treatment, and laser display. Applications. Uniform light spot can carry out uniform laser treatment on t...

AI Technical Summary

Problems solved by technology

The beam shaping system of the aspheric lens method is designed according to the principle of geometric optics. The system contains one or more aspheric lenses. The disadvantages are large volume, complex structure, heavy weight and high cost.

The beam shaping system of the diffractive optical element method is designed according to the principle of diffractive optics. The system usually includes a diffractive optical element and a focusing lens close to the diffractive optical element. The manufacturing process of the diffractive optical element is complicated, and it is difficult to integrate with the refractive lens and reduce the volume. , high cost and other disadvantages. At the same time, due to the immaturity of multiple photolithography processes, the phase distribution needs to be quantitatively designed, and it is difficult to achieve continuous phase change control to achieve more accurate wavefront control.

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