Quasi-Non-Diffractive Laser Beam Shaping for Uniform Deep Processing
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Solution Overview
Problem
Laser processing of partly transparent workpieces is challenging due to linear absorption of laser radiation, which affects the intensity distribution and efficiency of processing, differing from substantially transparent materials where linear absorption is negligible.
Innovation Solution
A method using a quasi-non-diffractive laser beam with an adjustable intensity distribution along the longitudinal direction is applied, where a pulsed raw laser beam is radiated into an optical beam shaping system to form a quasi-non-diffractive beam with a focal zone extending in the longitudinal direction, and the phase imposition is set to maintain a constant intensity distribution in the focal zone, compensating for linear absorption in partly transparent materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional laser beams are used for processing partly transparent workpieces, then the processing can be performed, but the intensity distribution becomes non-uniform due to linear absorption, reducing processing quality and efficiency
Solution Approach 1:
The patent changes the fundamental parameters of the laser beam by transforming it into a quasi-non-diffractive beam with specific phase distribution. This transformation modifies how the beam propagates through the material, maintaining constant intensity along the propagation direction despite linear absorption, thereby resolving the contradiction between processing quality and energy loss
Solution Approach 2:
Instead of trying to overcome absorption by increasing input energy, the patent inverts the approach by using a beam type (quasi-non-diffractive) that naturally maintains constant intensity. This inverted thinking transforms the problem from 'how to compensate for energy loss' to 'how to use a beam type that doesn't suffer from intensity degradation'
2Length of stationary object
If high-intensity laser radiation is used to overcome linear absorption, then processing depth can be increased, but the intensity distribution becomes non-uniform, affecting processing precision
Solution Approach 1:
The patent transforms the laser beam into a quasi-non-diffractive type with specific phase characteristics, which fundamentally changes the intensity distribution profile along the propagation direction. This parameter change enables deep processing while maintaining uniform intensity, thus achieving both increased processing depth and preserved precision
3Productivity
If conventional Gaussian beams are used, then the beam can be focused to a point, but the focal zone is limited in longitudinal extent, reducing processing efficiency for deep structures
Solution Approach 1:
Instead of using conventional focused beams with short focal zones, the patent inverts the approach by using quasi-non-diffractive beams that maintain their intensity profile over extended distances. This inverted beam type naturally provides both the needed focal zone extension and the intensity uniformity for efficient deep structure processing
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 approach enables efficient material processing of partly transparent workpieces by maintaining a consistent intensity distribution, allowing for modifications such as drilling, stress induction, and selective etching, similar to processing of substantially transparent materials, despite linear absorption.
Implementation Method 1
The optical beam shaping system is configured to impose a phase onto a beam cross section of the raw laser beam for forming phase-imposed laser radiation
Implementation Method 2
The workpiece includes a material that is partly transparent to the quasi-non-diffractive laser beam and exhibits an intensity-independent linear absorption in a frequency range of the quasi-non-diffractive laser beam
Implementation Method 3
radiating a pulsed raw laser beam into an optical beam shaping system in order to form a quasi-non-diffractive laser beam with a focal zone extending in a longitudinal direction
Implementation Method 4
The phase imposed on the beam cross section of the raw laser beam is set so that the intensity distribution of the quasi-non-diffractive laser beam in the focal zone is at least approximately constant in the longitudinal direction
Data Source
AI summary
A method for material processing of a workpiece includes radiating a pulsed raw laser beam into an optical beam shaping system in order to form a quasi-non-diffractive laser beam with a focal zone extending in a longitudinal direction for the material processing of the workpiece. The optical beam shaping system is configured to impose a phase onto a beam cross section of the raw laser beam for forming phase-imposed laser radiation. The method further includes focusing the phase-imposed laser radiation into the workpiece so that the quasi-non-diffractive laser beam is formed and the focal zone has an intensity distribution that is adjustable along the longitudinal direction. The phase imposed on the beam cross section of the raw laser beam is set so that the intensity distribution of the quasi-non-diffractive laser beam in the focal zone is at least approximately constant in the longitudinal direction.