Liquid Crystal Metasurface Beam Steering by Phase Bias Control
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Solution Overview
Problem
Current optical beam-steering technologies are limited in their ability to achieve precise and flexible beam steering and shaping, particularly in three-dimensional and two-dimensional applications, which is essential for advanced LiDAR systems and optical resonators.
Innovation Solution
Tunable optical metasurfaces with sub-wavelength optical resonant antennas and liquid crystal layers that apply voltage differential bias patterns to modify the reflection phase, enabling one-dimensional, two-dimensional beam steering, and spatial beamforming by adjusting the reflection phase patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical beam-steering technologies are used, then the system structure is relatively simple, but the beam steering precision and flexibility are insufficient
Solution Approach 1:
The metasurface is segmented into multiple independently controllable unit cells, each capable of individual phase modulation. This segmentation allows precise control of beam steering by adjusting each unit cell's liquid crystal orientation independently, achieving high-precision beam control while maintaining a relatively compact overall structure.
Solution Approach 2:
The metasurface incorporates liquid crystal materials that can dynamically change their optical properties in response to applied voltages. This dynamic tunability enables real-time adjustment of beam steering angles and shapes without mechanical movement, achieving precise and flexible beam control through electrical actuation of the liquid crystal molecules.
2Adaptability or versatility
If fixed beam steering angles are used, then the device operation is simple, but the adaptability to different applications is limited
Solution Approach 1:
The metasurface utilizes voltage-controlled liquid crystal orientation to change optical parameters such as refractive index and phase delay. By varying the applied voltage parameters, the beam steering angle and shape can be continuously adjusted across a wide range, providing high adaptability for different LiDAR applications while maintaining electronic control simplicity.
Solution Approach 2:
The liquid crystal metasurface design provides multi-functional capability by enabling both beam steering and beam shaping operations through the same device structure. The ability to independently control phase and amplitude across the aperture allows the system to perform multiple functions including focusing, collimation, and angular steering, enhancing versatility without requiring separate dedicated components.
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 precise control over beam steering angles and shapes, enhancing the capabilities of LiDAR systems and optical resonators for accurate distance measurement and optical sensing across various wavelengths, including infrared and visible ranges.
Implementation Method 1
Liquid crystal may be positioned around the optical resonant antennas, as a layer on top of the optical resonant antennas, and/or as part of the optical resonant antennas. A digital or analog controller may selectively apply varying voltage differentials across the liquid crystal within optical field regions of each of the optical resonant antennas.
Implementation Method 2
The voltage controller may apply a voltage differential bias pattern, such as a blazed grating pattern, to the metasurface to attain a target beam steering angle.
Data Source
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Figure 1C
AI summary
A tunable, optical metasurface can include an optically reflective surface to reflect optical radiation, such as infrared laser light. An array of optical resonant antennas may, for example, extend from or otherwise be positioned on the reflective surface with sub-wavelength spacings of, for example, less than one-half of a wavelength. Voltage-controlled liquid crystal may be positioned in the optical field region of each of the optical resonant antennas. A controller may apply a voltage differential bias pattern to the liquid crystal of optical resonant antennas, that may be arranged in tiled, interleaved, or randomly arranged subsets of optical resonant antennas to attain one-dimensional beam steering, two-dimensional beam steering, and/or spatial beam shaping.