Metasurface Pixel Structure for Quasi-Continuous Phase Modulation
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Solution Overview
Problem
Existing metasurface technologies face limitations in achieving stable quasi-continuous optical phase modulation due to binary modulation states and low control accuracy of phase change material crystallization degrees, restricting their application potential.
Innovation Solution
A pixel structure comprising an array of phase change units with independent excitation elements that can switch between crystalline and amorphous states, allowing for precise modulation of phase change states to achieve quasi-continuous phase modulation by adjusting the number of phase change units in different states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional phase change material is used for metasurface modulation, then binary modulation (two modulation states) is achieved, but the modulation precision and control accuracy are limited
Solution Approach 1:
The metasurface is divided into multiple pixel structures, with each pixel containing multiple phase change units (first and second phase change units). Each phase change unit can independently switch between crystalline and amorphous states, allowing the system to achieve more than binary modulation by controlling the combined states of multiple segments.
Solution Approach 2:
The patent transitions from binary modulation (two states) to multi-level modulation by introducing a spatial dimension - multiple phase change units arranged in series within each pixel. The combined states of these units enable quasi-continuous phase modulation (0, 1, 2, 3, 4 modulation states), effectively adding a dimension to the modulation space.
2Adaptability or versatility
If partial crystallization is used to achieve continuous modulation, then the number of modulation states increases, but the control accuracy and stability of crystallization degree are poor
Solution Approach 1:
Instead of controlling the crystallization degree of a single phase change material uniformly, the patent applies local quality control by using multiple discrete phase change units. Each unit can be independently controlled to be in a specific state (crystalline or amorphous), allowing precise control over the overall modulation state without the uncertainties of partial crystallization control.
Solution Approach 2:
The patent uses multiple copies of the same phase change unit structure (first and second phase change units with identical or similar configurations) to achieve multi-level modulation. This copying approach allows the system to overcome the limitations of single-unit partial crystallization by combining the states of multiple identical units, improving both the number of modulation states and control accuracy.
3Measurement precision
If multiple phase change units are arranged in series to achieve quasi-continuous modulation, then the phase modulation accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple phase change units into a single pixel structure that functions as an integrated modulation element. By arranging the first and second phase change units in series within the same pixel and sharing common excitation and ground electrodes, the system achieves quasi-continuous phase modulation while keeping the overall device structure compact and manageable, balancing complexity with functionality.
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
Enables high-speed and accurate optical wavefront modulation, enhancing the potential applications of metasurfaces in all-solid-state lidar and other optical devices by overcoming the limitations of binary modulation and improving control over phase change states.
Implementation Method 1
The phase change material can change the lattice inside the matter under external excitation (such as heat, laser, applied voltage, etc.), thus changing the dielectric constant greatly. The phase change material can be converted between crystalline state and amorphous state
Implementation Method 2
the excitation element comprises a first electrode and a second electrode, and an air gap is set between the first electrode and the second electrode; the first electrode and the second electrode are electrically connected by a middle element of the phase change unit; there is a potential difference between the first electrode and the second electrode, and a temperature of the middle element of the phase change unit is changed by an electro-thermal conversion
Data Source
AI summary
A pixel structure is provided, and the pixel structure includes a plurality of phase change units, and the plurality of phase change units are in identical; the plurality of phase change units are arranged in an array; each phase change unit includes an excitation element and a phase change element, and the excitation element is used for applying independent excitation to the phase change element to change a phase state of the phase change element; each phase change element comprises at least one nanostructure made of a phase change material; the phase state of the phase change element includes a crystalline state or an amorphous state; the phase change state of the pixel structure is related to the number of phase change units containing different phase change states.