Metalens Array Angular Field-of-View Control
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Solution Overview
Problem
Existing metasurface-based optical devices have limitations in controlling geometric aberrations and crosstalk due to constraints on the allowable field-of-view, which restricts their application in large field-of-view scenarios.
Innovation Solution
The design of meta-units and metasurfaces with angular-dependent transmission or reflection properties allows for the construction of metalenses with bounded angular field-of-views, which can be tiled into metalens arrays to extend overall angular and linear field-of-views, enabling large field-of-view two-dimensional and three-dimensional imaging while minimizing crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If existing metasurface-based optical devices are used, then compact optical systems can be constructed, but the field-of-view is constrained due to geometric aberrations and crosstalk
Solution Approach 1:
The patent divides the optical system into multiple metalens units arranged in an array, where each unit has a bounded local FOV. This segmentation allows the overall system to achieve a large combined FOV while each individual unit maintains controlled geometric aberrations and crosstalk through its bounded angular FOV design.
Solution Approach 2:
Each metalens unit in the array is designed with specific angular-dependent transmission properties that create a bounded local FOV. This local quality control ensures that geometric aberrations and crosstalk are minimized within each unit's operational range, while the collective array achieves extended overall FOV coverage.
2Adaptability or versatility
If the field-of-view is extended in existing metasurface devices, then large field-of-view imaging becomes possible, but geometric aberrations and crosstalk increase
Solution Approach 1:
By segmenting the optical system into multiple metalens units with bounded angular FOVs, the patent enables large overall FOV imaging while each segment independently controls geometric aberrations and crosstalk within its designated angular range, preventing these harmful factors from accumulating across the entire system.
Solution Approach 2:
The patent transitions from a single metalens design to a two-dimensional array of metalens units, adding a spatial dimension to the system architecture. This dimensional change allows the overall FOV to be extended by combining multiple bounded FOV units, while each unit maintains controlled aberrations and crosstalk through its angular filtering properties.
3Adaptability or versatility
If angular-dependent transmission properties are implemented, then bounded angular field-of-view can be achieved, but device complexity increases
Solution Approach 1:
The patent implements angular-dependent transmission properties by varying the geometric parameters (such as nanopost diameter, height, and spacing) of the meta-units across the metasurface. This parameter change approach enables bounded angular FOV control through the inherent angular sensitivity of resonant meta-units, achieving FOV management through geometric design rather than additional active control mechanisms.
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 enables compact imaging systems to achieve large field-of-view imaging with reduced crosstalk and geometric aberrations, suitable for applications in miniaturized devices, light-field cameras, and endoscopy.
Implementation Method 1
each meta-unit is configured with an angular-dependent transmission or reflection coefficient that decreases with an increasing incident angle of an illumination
Implementation Method 2
each meta-unit is configured with an angular-dependent transmission or reflection coefficient that decreases with an increasing incident angle of an illumination
Implementation Method 3
The disclosed metalens with bounded angular FOV can then be tiled into a metalens array to extend the overall angular and linear FOVs
Data Source
AI summary
A metalens and a metalens array having a bounded angular field of view are disclosed. The metalens includes a substrate and a two-dimensional (2D) grid over the substrate to divide the substrate into a 2D array of meta-units. Each meta-unit in the 2D array includes a nanostructure and a portion of the substrate that supports the nanostructure. Moreover, each meta-unit is configured with an angular-dependent transmission or reflection coefficient that decreases with an increasing incident angle of an illumination. Moreover, the metalens passes an incident light having an incident angle less than a cutoff angle and rejects an incident light having an incident angle greater than the cutoff angle. The metalens can be used a base unit for constructing a metalens array by tiling copies of the metalens into a 2D array of the metalens to achieve a significantly larger field-of-view.