Thermo-Optic Beam Shaping for Variable Laser BPP Control
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Solution Overview
Problem
High-power laser systems require frequent adjustments to the output optical system or optical fiber to vary the beam parameter product (BPP), which is time-consuming and costly, and can damage fragile components.
Innovation Solution
The BPP of a laser system is varied by manipulating input laser beams coupled into an optical fiber using a thermo-optic element with a spatially variable refractive index, achieved through local heating to create a temperature profile, allowing for controllable adjustment of the beam focus and quality without altering the output beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the output optical system or optical fiber is swapped out or realigned to vary the beam parameter product, then the beam quality and spot size can be adjusted for different processing applications, but the adjustment process is time-consuming, costly, and may damage fragile optical components
Solution Approach 1:
The patent applies dynamics by making the optical system adjustable in real-time through controlled deformation of a lens element. The lens curvature is dynamically changed using actuators (such as piezoelectric or voice coil actuators) that modify the lens shape without requiring physical replacement or manual realignment. This allows continuous variation of the beam parameter product during operation, resolving the contradiction between adaptability and adjustment time.
Solution Approach 2:
The patent changes the physical parameter of the lens (its curvature radius) to alter the optical system's behavior. By controlling the lens deformation parameter, the system achieves different beam focusing characteristics and spot sizes. This parameter-based control enables versatile beam adjustment without mechanical intervention, eliminating the time-consuming component swapping process while maintaining beam quality.
2Adaptability or versatility
If the output optical system or optical fiber is swapped out or realigned to vary the beam parameter product, then the beam quality and spot size can be adjusted for different processing applications, but the adjustment process is expensive and may damage fragile optical components
Solution Approach 1:
The dynamic lens deformation mechanism allows the optical system to adapt to different processing requirements without physical contact or mechanical stress on fragile components. The controlled deformation occurs within the lens's elastic limits, preventing damage while achieving the desired beam parameter changes. This eliminates the risk of component damage associated with repeated installation and removal of optical elements.
Solution Approach 2:
The patent replaces the mechanical system of physically swapping or manually realigning optical components with a field-based control system. Electrical or piezoelectric actuators generate forces that deform the lens without mechanical contact to the optical path, eliminating the harmful mechanical stresses that could damage fragile components while maintaining full adaptability.
3Adaptability or versatility
If frequent adjustments are made to the output optical system to vary the beam parameter product, then different processing applications can be accommodated, but the system complexity and cost increase
Solution Approach 1:
The patent implements multi-functionality by designing a single optical component (the deformable lens) that can perform multiple functions: focusing, beam shaping, and parameter adjustment. This universal element replaces the need for multiple specialized optical components or complex adjustment mechanisms, reducing overall system complexity while maintaining the ability to accommodate different processing applications through software-controlled lens deformation.
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 method enables flexible and efficient variation of the BPP without damaging the laser system, allowing for precise control of the beam spot size and quality for applications like welding and cutting, reducing the need for costly and time-consuming adjustments.
Implementation Method 1
A beam parameter product (BPP) of a laser beam is varied by local heating of a thermo-optic element to form a spatially variable temperature profile T(x) within the thermo-optic element, where x is a position vector within the thermo-optic element.
Implementation Method 2
The resulting variable temperature profile results in, via the thermo-optic effect, a variable index of refraction n within the thermo-optic element.
Data Source
AI summary
In various embodiments, a beam-parameter adjustment system and focusing system alters a spatial power distribution of a radiation beam, via thermo-optic effects, before the beam is coupled into an optical fiber or delivered to a workpiece.