# US 12,216,290 B2 · Color and multi-spectral image sensor based on 3D engineered material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,216,290 B2 - Document ID: US12216290B2 - Status: Granted - Kind: B2 - Application number: 17/853,540 - Filed: 2022-06-29 - Published: 2023-04-20 - Granted: 2025-02-04 - Earliest claimed: 2018-10-22 - Assignees: California Institute of Technology - Applicants: California Institute of Technology - Inventors: Philip Camayd-Munoz; Conner Ballew; Gregory Roberts; Andrei Faraon - Web page: https://patentgrep.com/patent/US12216290B2 ## CPC - G02B 27/1013: {for colour or multispectral image sensors, e.g. splitting an image into monochromatic image components on respective sensors (spectral imaging systems G01J)} - H01Q 15/10: comprising three-dimensional [3D] array of impedance discontinuities, e.g. holes in conductive surfaces or conductive discs forming artificial dielectric - G02B 1/002: {made of materials engineered to provide properties not available in nature, e.g. metamaterials} - G02B 5/0236: {the diffusion taking place within the volume of the element} - G02B 5/0278: {used in transmission} - H01P 1/207: Hollow waveguide filters (H01P1/212, H01P1/213, H01P1/215, H01P1/219 take precedence) - H10F 39/024: {of coatings or optical elements} - H10F 39/182: {Colour image sensors} - H10F 39/806: {Optical elements or arrangements associated with the image sensors} - H01Q 15/0086: {said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) - H01P: WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE (operating at optical frequencies G02B) - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION ## 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. ## Claims ### Claim 1 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; 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; and forming the 3D pattern using an optimization method employing a Gradient-based algorithm; 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; a sensitivity of the target function with respect to a refraction index at a point within the 3D structure is calculated based on a sigmoidal projection filter, the filter having a parameter to control a strength of the sigmoidal projection filter, wherein the sensitivity of the target function is calculated by: obtaining a uniform refraction index distribution based on an average of a maximum refraction index and a minimum refraction index; applying the sigmoidal filter to the uniform refraction index distribution, to obtain a filtered refraction index; adding the minimum refraction index to the filtered refraction index to obtain the refraction index at the point within the 3D structure, and increasing the strength of the sigmoidal projection filter from one iteration of the Gradient-based algorithm to another. ### Claim 2 (depends on 1) The method of claim 1, further comprising collecting each wave of the plurality of electromagnetic waves at a corresponding target area outside the 3D scattering structure. ### Claim 3 (depends on 2) The method of claim 2, wherein each target area corresponds to a sub-pixel of an image sensor. ### Claim 4 (depends on 1) The method of claim 1, further comprising, before the applying, building the 3D scattering structure by stacking up layers. ### Claim 5 (depends on 4) The method of claim 4, 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. ### Claim 6 (depends on 1) The method of claim 1, 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. ### Claim 7 (depends on 1) The method of claim 1, wherein: the sensitivity of the target function with respect to a refraction index at a point within the 3D structure is further 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. ### Claim 8 (depends on 7) The method of claim 7, wherein the second simulated electromagnetic waves are generated via a point source at the focal plane. ### Claim 9 (depends on 1) The method of claim 1, further comprising enforcing a minimum feature size for the optimizing the 3D pattern with the Gradient-based algorithm. ### Claim 10 (depends on 9) The method of claim 9, wherein the enforcing the minimum feature size is based on a dilated density.