Transmissive Metasurface Lens Integration for Thin Phase Control
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Solution Overview
Problem
Traditional refractive and diffractive optics are limited in their ability to impart phase shifts and require significant thickness and curvature, while metasurface elements offer subwavelength spacing and planar profiles, enabling advanced light shaping without curvature and thickness on the order of the wavelength, but their integration with light sources and detectors is not well-addressed.
Innovation Solution
Methods for fabricating metasurface elements involve depositing and patterning materials on a substrate, etching to form voids and features, and integrating them with light sources or detectors, using techniques like anisotropic etching, reactive ion etching, and wafer bonding to create multi-layer metasurface elements for advanced light manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional refractive optics are used to impart phase shifts, then the optical system achieves sufficient phase control, but the optical element thickness becomes 10-100 times larger than the wavelength of light
Solution Approach 1:
The optical element is segmented into multiple metasurface layers, each contributing a portion of the total phase shift. By dividing the phase modulation function across several thin layers with subwavelength spacing, the system achieves the required phase control without needing a single thick refractive element
Solution Approach 2:
The patent transitions from traditional three-dimensional refractive optics to two-dimensional metasurface structures. The phase control is achieved through in-plane geometric variations of subwavelength features rather than through thickness variations, effectively moving the optical function from the depth dimension to the lateral dimensions
2Manufacturing precision
If traditional refractive optics are used, then sufficient phase shift is achieved, but the optical elements require curvature for light shaping
Solution Approach 1:
The curved refractive surface is segmented into discrete planar metasurface elements with subwavelength features. Each element imparts phase shifts through its geometric structure rather than through continuous curvature, enabling light shaping without macroscopic curvature while maintaining phase control capability
Solution Approach 2:
The patent replaces the mechanical curvature of traditional lenses with a computational/geometric approach using metasurface patterns. The light shaping function traditionally achieved through curved surfaces is substituted by programmed phase distributions across planar metasurface elements
3Ease of manufacture
If binary diffractive optical elements are used, then manufacturing is simplified, but only two distinct phase shift values (0 or π) can be imparted
Solution Approach 1:
The patent changes the controlling parameter from binary state (present/absent) to continuous geometric parameters (feature size, shape, orientation) of subwavelength structures. By varying these geometric parameters, a continuous range of phase shifts from 0 to 2π can be achieved while maintaining compatibility with standard lithographic fabrication processes
4Adaptability or versatility
If multi-level diffractive optical elements are used to increase phase shift values, then more phase levels are achieved, but height variation of constituent elements along the optical axis is required
Solution Approach 1:
The patent moves the phase control mechanism from the vertical dimension (height variation along optical axis) to the lateral dimension (in-plane geometric variations). By modulating the size, shape, and orientation of subwavelength features within the plane of the metasurface, high-resolution phase control is achieved without requiring multi-level height structures
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 integration of metasurface elements with light sources and detectors enables efficient angular deflection and far-field illumination patterns, allowing for complex optical systems with reduced thickness and improved performance.
Implementation Method 1
metasurface features having feature sizes smaller than the wavelength of light within the specified operational bandwidth and configured to impose a phase shift on impinging light
Implementation Method 2
Metasurface elements are diffractive optics in which individual waveguide elements have subwavelength spacing
Implementation Method 3
etching the hard mask layer using an anisotropic etch process to form a plurality of voids and raised features corresponding to the array pattern in the hard mask
Implementation Method 4
etching to form voids and features, and integrating them with light sources or detectors, using techniques like anisotropic etching, reactive ion etching
Data Source
AI summary
Metasurface elements, integrated systems incorporating such metasurface elements with light sources and/or detectors, and methods of the manufacture and operation of such optical arrangements and integrated systems are provided. Systems and methods for integrating transmissive metasurfaces with other semiconductor devices or additional metasurface elements, and more particularly to the integration of such metasurfaces with substrates, illumination sources and sensors are also provided. The metasurface elements provided may be used to shape output light from an illumination source or collect light reflected from a scene to form two unique patterns using the polarization of light. In such embodiments, shaped-emission and collection may be combined into a single co-designed probing and sensing optical system.