Multi-Level Metasurface Structure for Broadband Optical Efficiency

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Solution Overview

Problem

Conventional refractive optical elements are large and inflexible, limiting the scalability of optical devices, and flat optical elements with metasurfaces face chromatic aberration issues due to being designed for specific wavelengths, making them less suitable for broadband light applications.

Innovation Solution

The development of multi-level metasurface structures with multiple layers, each tuned to specific wavelengths, which redirect light efficiently across a broader spectrum, reducing chromatic aberration and improving optical efficiency, while also being more cost-effective to manufacture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If conventional refractive optical elements are used, then optical devices can be manufactured, but the devices become large and inflexible, limiting scalability

Engineering Contradiction:

Improveoptical device sizeVSAvoidmanufacturing flexibility

Core Design Contradiction:

Volume of moving objectVSEase of manufacture

Solution Approach 1:

The optical element is segmented into multiple discrete layers, each performing a specific optical function. This segmentation allows independent optimization of each layer while maintaining overall compactness, resolving the contradiction between small size and manufacturing flexibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from conventional three-dimensional refractive optics to two-dimensional metasurface layers stacked in the third dimension. This dimensional change enables compact form factor while maintaining manufacturing flexibility through planar fabrication processes.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If flat optical elements with metasurfaces are used, then device size is reduced, but chromatic aberration occurs due to wavelength-specific design

Engineering Contradiction:

Improveoptical element thicknessVSAvoidoptical performance across bandwidth

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The optical system is divided into multiple metasurface layers, each optimized for specific wavelength ranges. This segmentation enables broadband operation by distributing different wavelength bands across different layers, reducing chromatic aberration while maintaining thin profile.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each metasurface layer is designed to handle multiple wavelength bands, and the stack collectively provides broadband optical functionality. This multi-functionality approach resolves the contradiction between thin design and broadband performance.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of manufacture

If single-layer metasurfaces are used, then manufacturing is simpler, but optical efficiency is reduced due to chromatic aberration

Engineering Contradiction:

Improvefabrication complexityVSAvoidoptical power loss

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

Multiple metasurface layers are merged into a single integrated optical element. This combination maintains manufacturing simplicity through standardized layer deposition processes while improving optical efficiency by eliminating chromatic aberration through the collective action of all layers.

Inventive Principle:

Principle #5Merging (Combining)

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

The multi-level metasurface structure achieves superior light convergence and reduced chromatic aberration, enabling more compact and efficient optical devices capable of handling broadband light, such as augmented reality displays, with lower production costs.

Implementation Method 1

metasurface 120 may induce a phase delay, which may be precisely tuned over a footprint of the array. The controlled phase delay redirects light 105 transmitted through flat lens 110 to a focal point 180.

Methodology Applied

Scientific EffectPhase delay:

Implementation Method 2

flat lens 110 can yield diffraction-limited optical performance

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 3

a given design will work perfectly (i.e., be diffraction limited) for only the target wavelength. Hence, flat lens 100 will have a different focal length for different wavelengths.

Methodology Applied

Scientific EffectChromatic aberration:

Data Source

PatentUS10365535B2Broadband flat optical elements and methods of manufacture

Publication Date: 2019.07.30 INTEL CORP

AI summary

Flat optical elements including a multi-level metasurface stack having two or more metasurface levels. Each metasurface level includes an arrangement of nanostructures, or protrusions, of one or more optically transmissive materials. A metasurface level may further include another optically transmissive material between the nanostructures, achieving a desired index contrast. Another metasurface level including additional nanostructures may be over a planar surface of this additional transmissive material. Another optically transmissive material may be between the additional nanostructures. This architecture may be followed for any number of levels, (e.g., a bi-layer, tri-layer, etc.). Each metasurface within the multi-level metasurface structure may be tuned to a particular optical wavelength. Such a multi-level metasurface may have greater bandwidth and/or achieve higher optical efficiency for a given band than a single metasurface. Molding techniques may be employed in metasurface fabrication to reduce the starting material cost and fabrication cost.