Coupling Prism Layout for Wide-Angle Optical Metasurface Steering
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Solution Overview
Problem
Current optical metasurface technologies face challenges in efficiently steering optical radiation over a wide range of angles while maintaining a compact design, as existing systems often require the optical radiation source to be positioned far from the metasurface to avoid blocking the steering aperture, limiting the angle of incidence and efficiency.
Innovation Solution
The use of a prism positioned relative to the tunable optical metasurface deflects optical radiation generated by the source onto the metasurface at a high angle of incidence, allowing the source to be closer without blocking the aperture, and further refracts steered radiation to extend the steering range beyond the metasurface's capabilities, using the difference in refractive indices between the prism and free space to achieve this.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the optical radiation source is positioned far from the metasurface to avoid blocking the steering aperture, then the aperture blocking is avoided, but the system size increases and the angle of incidence is limited
Solution Approach 1:
A coupling prism is introduced as an intermediary optical element between the VCSEL array and the metasurface. The prism receives optical radiation from the VCSELs and redirects it onto the metasurface at a high angle of incidence, enabling the VCSELs to be positioned close to the metasurface without blocking the steering aperture. This mediator resolves the spatial conflict between source positioning and aperture clearance.
Solution Approach 2:
The coupling prism utilizes angular redirection in a different spatial dimension, transforming the optical path from a direct linear arrangement to an angled incidence configuration. This dimensional change allows the optical source to be positioned in close proximity while maintaining unobstructed aperture access through angular separation of the optical paths.
2Area of stationary object
If the optical radiation source is positioned far from the metasurface, then the steering aperture is not blocked, but the steering angle range is limited
Solution Approach 1:
The coupling prism acts as an angular transformer, converting optical radiation from a limited angle range emitted by the VCSELs into a high angle of incidence on the metasurface. This angular transformation extends the effective steering angle range beyond what would be achievable with direct illumination, as the prism adds its own refraction angle to the metasurface steering capability.
3Volume of moving object
If the optical radiation source is positioned close to the metasurface, then the system size is reduced, but the steering aperture is blocked
Solution Approach 1:
The coupling prism serves as a spatial mediator that decouples the physical proximity requirement from the aperture blocking issue. By positioning the VCSELs close to the metasurface and using the prism to redirect their output at a high angle, the system achieves compact form factor while maintaining full aperture access for beam steering operations.
4Volume of moving object
If the optical radiation source is positioned close to the metasurface, then the system becomes more compact, but the angle of incidence is limited
Solution Approach 1:
The coupling prism functions as an angle multiplication device, taking the moderate emission angles from the VCSELs and transforming them into high angle of incidence on the metasurface through refraction. This enables the compact configuration to achieve the high incidence angles required for efficient metasurface operation and extended steering range.
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 configuration enables efficient steering of optical radiation over a broader range, from -120 to 120 degrees, while maintaining a compact design by allowing the optical source to be positioned closer to the metasurface, enhancing the system's angular range and operational efficiency.
Implementation Method 1
The use of a prism positioned relative to the tunable optical metasurface deflects optical radiation generated by the source onto the metasurface at a high angle of incidence
Implementation Method 2
further refracts steered radiation to extend the steering range beyond the metasurface's capabilities, using the difference in refractive indices between the prism and free space
Data Source
AI summary
According to various embodiments, a solid-state light detection and ranging (LiDAR) transmitter includes a tunable optical metasurface to selectively steer incident optical radiation long an azimuth axis. In some embodiments, different subsets of lasers in an array of lasers are activated to generate optical radiation for incidence on the metasurface at different angles of incidence on an elevation axis for unsteered deflection by the metasurface at corresponding angles of elevation. In some embodiments, a prism is positioned relative to the tunable optical metasurface to deflect the optical radiation from the optical assembly by the optical radiation source for incidence on the metasurface at an angle of incidence that is between the first steering angle and the second steering angle, such that the optical radiation incident on the metasurface and the steered output optical radiation from the metasurface spatially overlap within the prism.