3D Scattering Image Sensor for Multi-Spectral Light Sorting

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Solution Overview

Problem

Existing optical systems, including metasurfaces, face limitations in multi-functionality and efficiency due to the finite number of degrees of freedom, which restricts their ability to perform complex optical tasks such as sorting light by frequency, polarization, and incident angle.

Innovation Solution

The development of three-dimensional (3D) scattering elements designed via iterative gradient-based optimization, allowing for control of the refractive index with spatial resolution smaller than the smallest relevant wavelength, thereby enabling efficient encoding of various functionalities within a volume rather than at a single surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple metasurfaces are combined for more complex functionality, then multi-functionality is improved, but scattering efficiency decreases due to reduced efficiency that scales inversely with the number of simultaneous tasks

Engineering Contradiction:
Improvemulti-functionalityVSAvoidscattering efficiency
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent combines multiple optical functions (spectral filtering, polarization control, beam steering) into a single integrated metasurface device, eliminating the need for multiple separate metasurfaces while maintaining all functionalities and improving overall scattering efficiency

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The metasurface is designed to perform multiple optical functions simultaneously within a single device structure, including wavelength-dependent filtering, polarization-sensitive beam steering, and focusing, thereby achieving multi-functionality without the efficiency loss associated with stacking multiple specialized metasurfaces

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If the number of optical modes controlled by metasurfaces is increased, then functionality is improved, but the degree of performance is limited by the finite number of optical modes that can be controlled

Engineering Contradiction:
ImprovefunctionalityVSAvoidperformance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent utilizes the third dimension (vertical stacking of multiple metasurface layers with different orientations and functions) to expand the number of controllable optical modes beyond the limitations of single-plane metasurfaces, enabling independent control of multiple polarization states and spectral bands simultaneously

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If absorptive filters are used in image sensors, then color recording is achieved, but efficiency is limited to around 30% as most of the light is absorbed

Engineering Contradiction:
Improvecolor recording capabilityVSAvoidlight efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent converts the typically harmful effect of light absorption into a useful function by designing metasurface resonant structures that selectively absorb specific wavelengths and polarizations to achieve color filtering and polarization control, while the scattered and transmitted light is efficiently directed to appropriate pixels, thereby improving overall sensor efficiency beyond the 30% limitation of conventional absorptive filters

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach results in high-performance, multifunctional optical designs with improved efficiency, capable of sorting light with high accuracy across multiple spectral bands and polarizations, while maintaining a compact form factor.

Implementation Method 1

a three-dimensional (3D) scattering structure (201) functioning as a spectrum splitter. The 3D scattering structure (201) comprises a plurality of dielectric pillars (205) formed to scatter light in a predefined pattern.

Methodology Applied
Scientific EffectScattering: Scattering

Implementation Method 2

Incident light (202) passing through the 3D scattering structure (201) is scattered off the dielectric pillars.

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3871020B1Color and multi-spectral image sensor based on 3D engineered material
Publication Date: 2025.01.22 CALIFORNIA INST OF TECH
  • EP3871020B1 patent drawingFigure 1
  • EP3871020B1 patent drawingFigure 2A
  • EP3871020B1 patent drawingFigure 2A'

AI summary

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.