Polarization Converting Element with Independent Waveplate Rotation
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Solution Overview
Problem
Current laser machining technologies face limitations in machining speed due to the weight of waveplates and environmental susceptibility of organic thin films used for phase shift adjustment, leading to instability in producing fine circularly polarized light with low amplitude ellipticity.
Innovation Solution
A polarization state converting element comprising multiple waveplates made of non-rotatory, non-birefringent materials with applied phase delay functions, specifically two 1/8 waveplates, which can be independently rotated to adjust phase shifts and reduce amplitude ellipticity, enhancing machining precision and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional waveplates made of materials with optical rotatory property or birefringence are used for phase shift adjustment, then phase shift can be achieved, but the amplitude ellipticity increases and machining precision deteriorates
Solution Approach 1:
The invention extracts and eliminates the harmful optical rotatory property and birefringence from the waveplate material, retaining only the necessary phase delay function. This is achieved by selecting materials like metallic reflecting mirrors or dielectric multilayer films that provide phase shift without the detrimental effects of optical activity or birefringence, thereby reducing amplitude ellipticity and improving machining precision.
Solution Approach 2:
The invention applies different optical properties to different parts of the optical system. Specifically, the waveplate is designed to have localized phase delay capability through specific material layers or surface structures, while the bulk material maintains no optical rotatory property or birefringence. This localized approach allows phase adjustment without compromising overall polarization stability.
2Manufacturing precision
If organic thin films are used for phase shift adjustment, then phase shift can be achieved, but environmental susceptibility increases and reliability decreases
Solution Approach 1:
The invention replaces long-term unstable organic thin films with more stable inorganic materials or robust dielectric multilayer structures. While organic films may provide initial phase shift control, the patent adopts alternative materials that, although potentially requiring periodic recalibration, offer superior environmental stability and resistance to degradation from humidity, temperature, and other environmental factors.
Solution Approach 2:
The invention changes the material parameters of the waveplate from organic to inorganic or dielectric materials with different thermal and moisture stability characteristics. This parameter change transforms the waveplate's environmental response, making it resistant to humidity and temperature variations while maintaining phase shift functionality through adjustable azimuth angles.
3Ease of operation
If rotatable waveplates are used for polarization adjustment, then polarization state can be controlled, but the weight of moving parts increases and productivity decreases
Solution Approach 1:
The invention performs preliminary polarization state optimization during system setup or calibration phases. The waveplate's azimuth angle is pre-adjusted to optimal values that minimize amplitude ellipticity for specific machining applications. Once calibrated, the system operates without requiring continuous rotation or adjustment during high-speed machining, thereby maintaining productivity while preserving polarization control capability when needed.
Solution Approach 2:
The invention makes the waveplate's azimuth angle adjustable and rotatable, allowing dynamic adaptation to different machining requirements. The rotation mechanism enables the waveplate to be repositioned for different polarization states when changing workpiece orientations or machining directions, providing operational flexibility without requiring the waveplate to rotate continuously during machining operations.
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 solution enables stable production of fine circularly polarized light with small amplitude ellipticity, improving machining accuracy and durability by allowing on-site calibration and reducing environmental influences.
Implementation Method 1
a function of phase delay depending on polarization being applied on a surface of each waveplate
Implementation Method 2
the laser beam is changed to circularly polarized light while being changed in a direction thereof by the circularly polarizing mirror 20
Implementation Method 3
a rotation mechanism that rotates the respective waveplates independently to one another around an optical axis
Data Source
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AI summary
Provided is a polarization state converting element including a plurality of waveplates, and a rotation mechanism that rotates the respective waveplates independently of one another around an optical axis. The waveplates are each configured by a substrate made of a material having no optical rotatory property but having birefringence, or are each made of a material having neither optical rotatory property nor birefringence, but having transparency, a function of phase delay depending on polarization being applied on a surface of each waveplate.