Aluminum nitride metalens

Abstract

An aluminum nitride metalens comprises an ultraviolet-transmissive substrate and a nanostructure array protruding from the substrate. The substrate includes multiple substrate portions, and the nanostructure array includes multiple nanopillars arranged in an array. Each nanopillar is composed of aluminum nitride with birefringent properties. Each nanopillar and the substrate portion below it form a unit structure, and the lattice spacing of the unit structure is smaller than the wavelength of ultraviolet light. Through the birefringent aluminum nitride nanopillars, the aluminum nitride metalens not only allows ultraviolet light to pass through without absorbing it, but also allows for comprehensive control of the phase changes of ultraviolet light. This gives the aluminum nitride metalens excellent polarization conversion efficiency in controlling ultraviolet light, and it can be used to control the phase, amplitude, polarization, and other properties of ultraviolet light.

Claims

1. An aluminum nitride superlens, comprising: a substrate that is permeable to ultraviolet light, the substrate including a plurality of substrate portions; and a nanostructure array protruding from the substrate, the nanostructure array including a plurality of nanopillars arranged in an array, each nanopillar being composed of aluminum nitride having birefringence properties; each nanopillar and the substrate portion below it forming a unit structure, the lattice spacing of the unit structure being smaller than the ultraviolet light wavelength.

2. The aluminum nitride metalens as described in claim 1, wherein, In these unit structures, the nanopillars are generally cuboids, the substrate portions are regular hexagons, and the substrate portions are closely arranged in a honeycomb pattern. The nanostructure array has a phase profile that conforms to the following formulas [A] to [D]:

3. The aluminum nitride metalens as described in claim 2, wherein, The phase profile also conforms to the following formula [E] or [F]:

4. The aluminum nitride metalens as described in claim 2, wherein, The phase profile also conforms to the following equations [G] to [H]:

5. The aluminum nitride meta-lens as described in any one of claims 1 to 4, wherein, The thickness of this aluminum nitride superlens does not exceed 2 mm.

6. The aluminum nitride meta-lens as described in any one of claims 1 to 4, wherein, The substrate is made of a material with a bandgap greater than 3.5 eV.

7. The aluminum nitride meta-lens as described in any one of claims 1 to 4, wherein, The maximum width of this nanostructure array ranges from 10 μm to 10 mm.

8. The aluminum nitride meta-lens as described in any one of claims 2 to 4, wherein, The average length of these nanopillars is less than the wavelength of ultraviolet light, the average width is less than the wavelength of ultraviolet light, the average height is between 150 nm and 1000 nm, and the height difference between these nanopillars does not exceed 100 nm.

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