Single nanostructure-integrated metalens

Patent metadata

Field	Value
Publication number	US-2023375747-A1
Application number	US-202217746508-A
Country	US
Kind code	A1
Filing date	May 17, 2022
Priority date	May 17, 2022
Publication date	Nov 23, 2023
Grant date	—

Abstract

Systems and methods which provide single nanostructure-integrated metalens configurations implementing projector and light shaper functionality are described. A single nanostructure-integrated metalens may comprise an optical substrate having a preconfigured mapping of integrated nanostructures providing metasurfaces for modulating the behaviors of electromagnetic waves to implement a thin, flat lens. A period distance for the nanostructures, a height of the nanostructures, and a quantization for lateral sizes of the nanostructures may be selected for a particular single nanostructure-integrated metalens configuration. A first phase map may be computed with respect to structured light generation and a second phase map may be computed with respect to light collimation, wherein fusion of these phase maps may be used to define a preconfigured mapping for the nanostructures of a single nanostructure-integrated metalens implementation. The phase distribution of the first phase map may be inverse designed, such as using an inverse phase design technique.

First claim

What is claimed is:

1 . A metalens comprising:
an optical substrate having a transparent spectral range of at least 50 nm corresponding to an operation wavelength of a light emission device to be used with the metalens; and a plurality of nanostructures integrated on at least one surface of the optical substrate in accordance with a phase distribution of a phase mapping configured for providing both light collimation functionality and structured light projection functionality, wherein the nanostructures are provided in at least 4 quantized lateral sizes and are spaced according to a period distance (P), wherein P is in a range from (λ c *0.8)/2 to (λ c *1.2)/2, and wherein λ c is an operation wavelength region of the metalens.

2 . The metalens of claim 1 , wherein the plurality of nanostructures each have a same height (H), and wherein H in a range from λ c /10 to λ c .

3 . The metalens of claim 1 , wherein the plurality of nanostructures comprise a material having a refractive index with respect the operation wavelength region of the metalens not smaller than 1.5.

4 . The metalens of claim 1 , wherein the plurality of nanostructures comprise a plasmonic metallic material.

5 . The metalens of claim 1 , wherein the phase mapping is provided at least in part by an inverse calculation iterative Fourier transform algorithm (IFTA) based on a target image, and the phase mapping is provided at least in part based on a calculation for phase focusing light to a nanostructure layer of the plurality of nanostructures.

6 . The metalens of claim 5 , wherein the inverse calculation IFTA based on the target image utilizes a distance between adjacent dots in a first axis (d x ) of a plane of the target image, a distance between adjacent dots in a second axis (d y ) of the plane of the target image, and an offset distance (f m ) of lateral shift between alternate rows of dots of the target image, wherein the first axis and the second axis are perpendicular.

7 . The metalens of claim 1 , wherein the nanostructures are provided in 4 or 8 quantized lateral sizes.

8 . The metalens of claim 7 , wherein the nanostructures are provided in 4 quantized lateral sizes corresponding to 4 levels of phase change, wherein the 4 levels of phase correspond to phase changes of π/2, π, 3π/2, and 2π, and wherein the nanostructures are configured to have a same spatial resolution in x and y axes.

9 . The metalens of claim 1 , wherein the metalens is disposed in a support structure of a projector device including the light emission device, the support structure, and the metalens, and wherein the metalens is oriented in the support structure so that a first surface of the at least one surface of the optical substrate having nanostructures of the plurality of nanostructures integrated thereon faces the light emission device.

10 . A method for providing a metalens configured for providing both light collimation functionality and structured light projection functionality, the method comprising:
determining corporeal aspects with respect to nanostructures for a particular configuration of a single nanostructure-integrated metalens comprising the metalens, wherein the corporeal aspects include a period distance (P) with respect to the nanostructures and sizes with respect to the nanostructures, wherein the period distance comprises a row-to-row and column-to-column center distance implemented with respect to adjacent ones of the nanostructures, and wherein the sizes provide at least 4 quantized lateral sizes for the nanostructures corresponding to levels of phase change to be implemented by the nanostructures; determining a mapping of the nanostructures for integration upon a surface of an optical substrate of the metalens implementing projector and light shaper functionality by a single nanostructure-integrated metalens comprising the metalens, wherein determining the mapping of the nanostructures comprises:
determining a structured light phase map using an inverse designed phase distribution based upon a target image;
determining a collimation light phase map using a phase focusing design technique; and
fusing the structured light phase map and the collimation light phase map to provide a preconfigured mapping for the nanostructures for the single nanostructure-integrated metalens providing desired spatial pattern of optical phase changes according to the mapping of the nanostructures; and
integrating the nanostructures having the corporeal aspects upon the optical substrate according to the mapping to provide the metalens for use as the single nanostructure-integrated metalens.

11 . The method of claim 10 , wherein P is in a range from (λ c *0.8)/2 to (λ c *1.2)/2, and wherein λ c is an operation wavelength region of the metalens.

12 . The method of claim 11 , further comprising:
determining a height (H) of the nanostructures, wherein H in a range from λ c /10 to λ c and the height of each of the nanostructures is a same value of H.

13 . The method of claim 10 , wherein determining the structured light phase map uses an inverse calculation iterative Fourier-transform algorithm (IFTA) based on the target image.

14 . The method of claim 13 , wherein determining the collimation light phase map uses a binary diffractive phase function.

15 . The method of claim 14 , wherein fusing the structured light phase map and the collimation light phase map uses a convolution of a surface function.

16 . The method of claim 10 , further comprising:
disposing the metalens in a support structure of a projector device including a light emission device, the support structure, and the metalens, wherein the metalens is oriented in the support structure so that a first surface of the optical substrate having the nanostructures integrated thereon faces the light emission device.

17 . A light projector apparatus comprising:
a single nanostructure-integrated metalens, wherein the single nanostructure-integrated metalens comprises:
an optical substrate having a spectral range of at least 50 nm corresponding to an operation wavelength of a light emission device to be used with the single nanostructure-integrated metalens; and
a plurality of nanostructures integrated on at least one surface of the optical substrate in accordance with a phase distribution of a phase mapping configured for providing both light collimation functionality and structured light projection functionality, wherein the nanostructures are provided in at least 4 quantized lateral sizes and are spaced according to a period distance (P), wherein P is in a range from (λ c *0.8)/2 to (λ c *1.2)/2, and wherein λ c is an operation wavelength region of the single nanostructure-integrated metalens;
the light emission device having one or more light sources configured to provide emission of light in a light emission plane of the light emission device, wherein the one or more light sources emit light having a center wavelength of λ c ; and a support structure configured to hold the single nanostructure-integrated metalens in a desired predetermined relationship with the light emission plane of the light emission device, wherein the support structure is configured to hold the single nanostructure-integrated metalens oriented in the support structure so that a first surface of the optical substrate having nanostructures of the plurality of nanostructures integrated thereon faces the light emission device.

18 . The light projector apparatus of claim 17 , wherein the light emission device has a plurality of light sources num

Assignees

• Hong Kong Applied Science & Tech Research Inst Co Ltd

Inventors

• Lai Yunhe
• Bai Haoyuan
• Yang Qingyi
• Jiang Jinbo

Classifications

• G02B1/002 Primary

  made of materials engineered to provide properties not available in nature, e.g. metamaterials · CPC title

• G02B27/30

  Collimators · CPC title

• G02B27/0012

  Optical design, e.g. procedures, algorithms, optimisation routines · CPC title

• G02B2207/101

  Nanooptics · CPC title

• G01B11/22

  for measuring depth · CPC title