Multilayered meta lens and optical apparatus including the same

Abstract

A meta-lens includes a first layer that is arranged on a substrate and that includes a plurality of first nanostructures and a second layer including a plurality of second nanostructures separately arranged from the first nanostructures. The meta-lens may focus light of a plurality of wavelengths or light of a wide wavelength bandwidth due to the arrangement of the nanostructures in a multilayer structure.

What is claimed is: 
     
         1 . An image sensor comprising:
 a sensor substrate including a first photo-sensing cell, second photo-sensing cell and a third photo-sensing cell;   a first meta-lens arranged to face the first photo-sensing cells, on the sensor substrate;   a second meta-lens arranged to face the second photo-sensing cells, on the sensor substrate; and   a third meta- lens arranged to face the third photo-sensing cells, on the sensor substrate;   wherein   the first meta-lens comprises a plurality of first nanostructures and a plurality of second nanostructures that form a layer different from a layer of the plurality of the first nanostructure,   the second meta-lens comprises a plurality of third nanostructures and a plurality of fourth nanostructures that form a layer different from a layer of the plurality of the third nanostructure, and   the third meta-lens comprises a plurality of fifth nanostructures and a plurality of sixth nanostructures that form a layer different from a layer of the plurality of the fifth nanostructure.   
     
     
         2 . The image sensor of  claim 1 , wherein
 a shape distribution of the first nanostructures and the second nanostructures is configured to focus lights of different wavelengths in a first wavelength bandwidth, on the first photo-sensing cell,   a shape distribution of the third nanostructures and the fourth nanostructures is configured to focus lights of different wavelengths in a second wavelength bandwidth on the second photo-sensing cell, and   a shape distribution of the fifth nanostructures and the sixth nanostructures is configured to focus lights of different wavelengths in a third wavelength bandwidth on the third photo-sensing cell.   
     
     
         3 . The image sensor of  claim 2 , wherein the first wavelength bandwidth, the second wavelength bandwidth, and the third wavelength bandwidth is a red wavelength bandwidth, a green wavelength bandwidth and a blue wavelength bandwidth, respectively. 
     
     
         4 . The image sensor of  claim 1 , further comprises:
 a substrate supporting a plurality of first, third, fifth nanostructures; and   a spacer layer covering the plurality of first, third, fifth nanostructures and supporting the plurality of second, fourth, and sixth nanostructures.   
     
     
         5 . The image sensor of  claim 4 , wherein the substrate comprising a material having a refractive index different form the refractive index of the plurality of first, third, fifth nanostructures, and
 wherein the spacer layer comprising a material having a refractive index different from the refractive index of the plurality of first, second, third, fourth, fifth and sixth nanostructures.   
     
     
         6 . The image sensor of  claim 4 , wherein the refractive index of the substrate is less than the refractive index of the plurality of first, third and fifth nanostructures , and
 wherein the refractive index of the spacer layer is less than the refractive index of the plurality of first second, third, fourth, fifth and sixth nanostructures.   
     
     
         7 . The image sensor of  claim 4 , wherein a difference between the refractive index of the substrate and the refractive index of the plurality of first nanostructures is 0.5 or greater. 
     
     
         8 . The image sensor of  claim 4 , wherein a difference between the refractive index of the plurality of first nanostructures and the refractive index of the spacer layer is 0.5 or greater. 
     
     
         9 . The image sensor of  claim 4 , further comprising:
 a protection layer covering the plurality of second, fourth and sixth nanostructures.   
     
     
         10 . The image sensor of  claim 9 , wherein a difference between a refractive index of the protection layer and the refractive index of the plurality of second nanostructures is 0.5 or greater. 
     
     
         11 . The image sensor of  claim 1 , wherein a height of the plurality of first, second, third, fourth, fifth and sixth nanostructures are in a range from λ/3 to (3λ)/2, where λ is a longer wavelength of the first wavelength and the second wavelength, wherein a direction of the height is a direction of stacking the layer of the plurality of first nanostructures and the layer of the plurality of second nanostructures. 
     
     
         12 . The image sensor of  claim 1 , wherein a separation distance between the plurality of first nanostructures and the plurality of second nanostructures, a separation distance between the plurality of third nanostructures and the plurality of fourth nanostructures, and a separation distance between the plurality of fifth nanostructures and the plurality of sixth nanostructures in the stacking direction are in a range from λ/4 to 2λ, where λ is a longer wavelength of the first wavelength and the second wavelength. 
     
     
         13 . The image sensor of  claim 1 , wherein the first meta-lens, the second meta-lens and the third meta-lens are monolithically formed on the sensor substrate. 
     
     
         14 . An imaging lens comprising:
 a first meta-lens comprising a plurality of first nanostructures and a plurality of second nanostructures that form a layer different from a layer of the plurality of the first nanostructure;   a second meta-lens comprises a plurality of third nanostructures and a plurality of fourth nanostructures that form a layer different from a layer of the plurality of the third nanostructure; and   a third meta-lens comprises a plurality of fifth nanostructures and a plurality of sixth nanostructures that form a layer different from a layer of the plurality of the fifth nanostructure;   wherein the imaging lens is configured to form am optical image of an object on an imaging surface and the first meta-lens, the second meta-lens, and the third meta-lens are arranged along an optical path from an object to the imaging surface, and   wherein at least one of the first, second, third meta-lens have a positive refractive power, and at least one of the first meta-lens, the second meta-lens, and the third meta-lens have a negative refractive power.   
     
     
         15 . The imaging lens of  claim 14 , wherein
 a shape distribution of the first and second nanostructures is configured to focus light of a wavelength bandwidth including the first wavelength and the second wavelength with a first focal length,   a shape distribution of the third and fourth nanostructures is configured to focus light of a wavelength bandwidth including the first wavelength and the second wavelength with a second focal length,   a shape distribution of the fifth and sixth nanostructures is configured to focus light of a wavelength bandwidth including the first wavelength and the second wavelength, and   wherein the wavelength bandwidth comprises one from among a red wavelength bandwidth, a green wavelength bandwidth, and a blue wavelength bandwidth.   
     
     
         16 . The imaging lens of  claim 15 , wherein the wavelength bandwidth comprises a red wavelength bandwidth, a green wavelength bandwidth, and a blue wavelength bandwidth. 
     
     
         17 . The imaging lens of  claim 14 , wherein the first meta-lens, second meta-lens, and the third meta-lens further comprises respectively:
 a first, a second, a third substrate each supporting the plurality of first, third, fifth nanostructures, respectively;   a first, a second, a third spacer layer each covering the plurality of first, third, fifth nanostructures and supporting the plurality of second, fourth, sixth nanostructures, respectively; and   a first, a second, a third protection layer each covering the plurality of second, fourth, sixth nanostructures, respectively.   
     
     
         18 . The imaging lens of  claim 17 , wherein
 a difference between a refractive index of the first substrate and a refractive index of the plurality of first nanostructures is 0.5 or greater,   a difference between a refractive index of the first nanostructures and a refractive index of the first spacer is 0.5 or greater, and   a difference between a refractive index of the second nanostructures and a refractive index of the first protection layer is 0.5 or greater.   
     
     
         19 . The imaging lens of  claim 14 , wherein a height of the plurality of first, second, third, fourth, fifth and sixth nanostructures are in a range from λ/3 to (3λ)/2, where λ is a longer wavelength of the first wavelength and the second wavelength, wherein a direction of the height is a direction of stacking the layer of the plurality of first nanostructures and the layer of the plurality of second nanostructures. 
     
     
         20 . The imaging lens of  claim 14 , wherein a separation distance between the plurality of first nanostructures and the plurality of second nanostructures, a separation distance between the plurality of third nanostructures and the plurality of fourth nanostructures, and a separation distance between the plurality of fifth nanostructures and the plurality of sixth nanostructures in the stacking direction are in a range from λ/4 to 2λ, where λ is a longer wavelength of the first wavelength and the second wavelength.