Geometric Phase Lens Polarization Splitter for Compact Optical Systems
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Solution Overview
Problem
Existing polarization splitter devices have a fixed separation angle and are bulky due to their prism-based construction, limiting their adjustability and application in thin, compact optical systems.
Innovation Solution
A polarization splitter device utilizing two geometric phase lenses with adjustable separation angle, achieved by transverse shifting and rotating the lenses, allowing for flexible adjustment of the separation angle and maintaining a thin profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional prism-based polarization separator devices are used, then the separation of polarized light beams is achieved, but the device thickness and volume increase significantly
Solution Approach 1:
The patent changes the fundamental optical parameters by switching from prism-based geometric optics to geometric phase lenses that operate with circular polarization states. This parameter change enables thin-profile polarization separation because geometric phase lenses can achieve the required phase modulation in a much shorter optical path compared to traditional prisms that rely on oblique surfaces and material birefringence over long distances
Solution Approach 2:
The patent replaces the mechanical/prism-based system with a geometric phase lens system that uses spatially varying optical properties rather than physical geometry. The geometric phase lenses modulate the phase of circularly polarized light through their optical structure, eliminating the need for thick prism assemblies and oblique surfaces while maintaining polarization separation functionality
2Ease of manufacture
If fixed-angle prism polarization separators are used, then manufacturing is simplified, but the separation angle cannot be adjusted
Solution Approach 1:
The patent introduces dynamic adjustability by making the separation angle variable rather than fixed. The geometric phase lenses are positioned at adjustable distances from each other along the optical axis, and their relative transverse positions can be modified. This dynamic configuration allows the separation angle to be tuned after manufacturing, providing versatility while the lenses themselves can be manufactured using standard optical fabrication techniques
Solution Approach 2:
The patent divides the polarization separation function into two independent geometric phase lenses rather than a single monolithic prism. This segmentation allows each lens to be manufactured separately with standard techniques, and then assembled in adjustable configurations, combining manufacturing simplicity with post-fabrication adjustability of the separation angle
3Area of stationary object
If large section beam handling is required, then the component size increases, but the beam section remains limited by the component dimensions
Solution Approach 1:
The patent employs thin geometric phase lens structures that function as optical elements with minimal thickness. These lenses can be manufactured as thin optical components that maintain large clear apertures for handling large beam sections. The thin-film-like nature of geometric phase lenses allows them to provide the required phase modulation without the thickness penalties of traditional prism systems, enabling large beam handling in a compact form factor
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 adjustable separation angle and compact design, suitable for applications requiring large beam handling without increased thickness, such as in imaging systems, while maintaining high precision and efficiency.
Implementation Method 1
a first geometric phase lens, having a first optical center, a first optical axis and a first positive focal length for a first state of circular polarization and an opposite focal length for another state of circular polarization orthogonal to the first circular polarization state
Implementation Method 2
They are based on the use of two prisms made of birefringent materials. These prisms separate an incident light beam into two emerging light beams each having a linear polarization and the polarizations of the two emerging light beams are orthogonal.
Data Source
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AI summary
The invention relates to a polarisation separation device for receiving an incident light beam (100). According to the invention, the device comprises a first geometric-phase lens (L1), having a first optical centre (O1), a first optical axis (Z)1) and a first focal length (F1), and a second geometric-phase lens (L2), having a second optical centre (O2), a second optical axis (Z2) and a second focal length (F2), the first and the second geometric-phase lenses being separated from each other by a first distance (D) along the first optical axis (Z1), the first geometric-phase lens (L1) and the second geometric-phase lens (L2) being arranged so as to have an optical power of the same sign for a first circular polarisation state and an optical power of the opposite sign for another circular polarisation state orthogonal to the first circular polarisation state, the device being configured and oriented such that a projection (P1) of the first optical centre (O1) along the first optical axis (Z1) on the second geometric-phase optical lens (L2) is located at a second non-zero distance (e) from the second optical centre (O2).