Color and multi-spectral image sensor based on 3d engineered material

Patent metadata

Field	Value
Publication number	US-2020124866-A1
Application number	US-201916656156-A
Country	US
Kind code	A1
Filing date	Oct 17, 2019
Priority date	Oct 22, 2018
Publication date	Apr 23, 2020
Grant date	—

Abstract

Methods and devices to build and use multi-functional scattering structures. The disclosed methods and devices account for multiple target functions and can be implemented using fabrication methods based on two-photon polymerization or multi-layer lithography. Exemplary devices functioning as wave splitters are also described. Results confirming the performance and benefits of the disclosed teachings are also described.

First claim

What is claimed is:

1 . A three-dimensional (3D) scattering structure formed into a set 3D pattern based on one or more set target functions, wherein the 3D scattering structure is configured to:
receive electromagnetic waves; and scatter the electromagnetic waves to provide the one or more set target functions.

2 . The 3D scattering structure of claim 1 formed through stacked layers, wherein the set 3D pattern is produced using a combination of two-dimensional (2D) dielectric structures, and
wherein each stacked layer comprises:
a dielectric layer above a substrate; and
a 2D pattern on the dielectric layer, the 2D pattern comprising an etched-away 2D structure in accordance with the one or more set target functions.

3 . The 3D scattering structure of claim 1 , wherein the one or more target functions are based on sorting the electromagnetic waves into one or more target areas and wherein the sorting is performed according to 1) one or more wavelengths, 2) one or more polarizations, 3) an incident angle of the electromagnetic waves, 4) spatial distribution, or a combination thereof.

4 . The 3D scattering structure of claim 3 , wherein:
the one or more wavelengths comprises wavelengths corresponding to colors red, green, and blue; and the one or more polarizations comprises one or more polarization orientations.

5 . An image sensor comprising the 3D structure of claim 3 , wherein the one or more target areas comprises one or more pixels.

6 . An image sensor comprising the 3D scattering structure of claim 4 , wherein the one or more target areas comprises a first subpixel in correspondence with a color red, a second subpixel in correspondence with a color blue, a third subpixel in correspondence with a color green with a first polarization orientation, and a fourth subpixel in correspondence with the color green with a second polarization orientation, and wherein the first, second, third and fourth sub-pixels are adjacent sub-pixels.

7 . A camera comprising a plurality of image sensors of claim 5 .

8 . The 3D scattering structure of claim 2 , wherein each layer of the plurality of layers is 2 um by 2 um with a thickness of 400 nm.

9 . The 3D scattering structure of claim 3 , operating within a wavelength range of 400 nm to 700 nm.

10 . The 3D scattering structure of claim 2 , wherein the dielectric layer comprises TiO2 and the substrate comprises SiO2.

11 . The 3D scattering structure of claim 1 , made of a porous polymer cube or a cluster of silicon particles embedded in a silica matrix.

12 . The 3D scattering structure of claim 2 , made of a material transparent at visible frequencies.

13 . A microwave filter comprising the 3D scattering structure of claim 1 .

14 . A method of splitting an electromagnetic wave into a plurality of waves with different wavelengths, the method comprising:
applying the electromagnetic wave to a three-dimensional (3D) scattering structure at a first side thereof, the 3D scattering structure being formed into a set 3D pattern; and scattering off the electromagnetic wave to generate a plurality of electromagnetic waves with different wavelengths, the plurality of electromagnetic waves exiting the 3D scattering structure at output second side thereof.

15 . The method of claim 14 , further comprising collecting each wave of the plurality of electromagnetic waves at a corresponding target area outside the 3D scattering structure.

16 . The method of claim 15 , wherein each target area corresponds to a sub-pixel of an image sensor.

17 . The method of claim 14 , further comprising, before the applying, building the 3D scattering structure by stacking up layers.

18 . The method of claim 17 , further comprising forming each layer by:
growing a dielectric layer above a substrate; transferring a 2D pattern onto the dielectric layer; and etching away an unprotected material.

19 . The method of claim 14 , further comprising optimizing the 3D pattern with a Gradient-based algorithm.

20 . The method of claim 19 , further comprising, before the applying, building the 3D scattering structure by:
focusing a laser on a liquid polymer, thereby causing the liquid polymer to cross-link and harden at a laser focus; and moving the laser focus in accordance with an objective function of the Gradient-based algorithm.

21 . The method of claim 19 , wherein:
a target function of the Gradient-based algorithm is defined based on an electromagnetic intensity of the electromagnetic wave at target locations in a focal plane arranged outside the 3D structure; and a sensitivity of the target function with respect to a refraction index at a point within the 3D structure is calculated based on:
a first set of electric fields corresponding to a first simulated electromagnetic waves applied to the first side; and
a second set of electric fields corresponding to a second simulated electromagnetic waves applied to the second side.

22 . The method of claim 21 , wherein the second simulated electromagnetic waves are generated via a point source at the focal plane.

23 . The method of claim 22 , wherein the sensitivity is calculated with respect to an auxiliary density being a function of the refractive index.

24 . The method of claim 23 , wherein the function is defined based on a sigmoidal projection filter definition.

25 . An imaging method comprising performing the method of claim 14 , the imaging method being selected from a hyperspectral, thermal or optical imaging method.

Assignees

• California Inst Of Techn

Inventors

• Camayd-Munoz Philip
• Ballew Conner
• Roberts Gregory
• Faraon Andrei

Classifications

• H01Q15/0086

  said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials · CPC title

• H01Q15/10 Primary

  comprising three-dimensional [3D] array of impedance discontinuities, e.g. holes in conductive surfaces or conductive discs forming artificial dielectric · CPC title

• G02B27/1013 Primary

  for colour or multispectral image sensors, e.g. splitting an image into monochromatic image components on respective sensors (spectral imaging systems G01J) · CPC title

• G02B5/0236

  the diffusion taking place within the volume of the element · CPC title

• H01P1/207

  Hollow waveguide filters (H01P1/212, H01P1/213, H01P1/215, H01P1/219 take precedence) · CPC title