Segmented Beam-Shaping Element for Diffraction-Free Laser Modification
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Solution Overview
Problem
Existing laser processing technologies struggle to create elongate, high-aspect-ratio modifications in transparent materials without diffraction effects, which can affect the quality and geometry of modifications in the material.
Innovation Solution
A diffractive optical element with a sheet-like grating structure is used to impose a two-dimensional phase distribution on a laser beam, forming radially symmetrical phase profiles with varying segment grating phases and periods to create diffraction-free beam profiles that are elongate in the direction of propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional laser beams are used for processing transparent materials, then the laser beam can propagate through the material, but diffraction effects occur that degrade the beam profile and modification quality along the propagation direction
Solution Approach 1:
The beam-shaping element is divided into multiple angular segments, where each segment is assigned a specific phase value. This segmentation allows independent phase control in different angular regions, enabling the formation of a diffraction-free beam profile by compensating for diffraction effects in each segment while maintaining overall beam integrity through the superposition of segmented wavefronts.
2Shape
If the beam profile is modified to achieve high aspect ratio modifications, then the modification geometry improves, but diffraction effects increase and degrade the beam profile consistency
Solution Approach 1:
Different phase values are assigned to different angular segments of the beam profile, creating local quality variations in the wavefront. This local phase modulation allows the beam to maintain a consistent diffraction-free profile along the propagation direction while achieving the desired high aspect ratio modification geometry, as each local segment contributes to the overall shaped beam profile without suffering from diffraction degradation.
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 allows for the formation of continuous, high-aspect-ratio modifications in transparent materials without diffraction, improving the quality and consistency of laser processing.
Implementation Method 1
Segmented beam-shaping element and laser processing installation... diffractive optical element for imposing a phase distribution on a transverse beam profile... surface elements that adjoin one another and form a sheet-like grating structure
Data Source
AI summary
A diffractive optical element for imposing a phase distribution on a transverse beam profile of a laser beam includes surface elements that adjoin one another and form a sheet-like grating structure. Each surface element is assigned a phase shift value. The phase shift values define a two-dimensional phase distribution. The two-dimensional phase distribution has a beam center position, which defines a radial direction in the sheet-like grating structure. The surface elements are assigned to a plurality of angle segments. Each angle segment has an azimuthal segment width with respect to the beam center position. The phase shift values in the angle segments form radially symmetrical phase profiles respectively with respect to the beam center position. The radially symmetrical phase profiles form in the radial direction grating functions that have a same grating period. A segment grating phase is assigned to each of the grating functions.