Beam Shaping Apparatus for Linear Intensity Distribution
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Solution Overview
Problem
Existing beam shaping devices struggle to effectively focus and homogenize laser radiation with high diffraction indices, leading to poor beam quality and interference issues during superimposition of partial beams.
Innovation Solution
The device employs beam transformation means that swap the diffraction indices and spatial coherence properties between two directions, allowing for significant reduction in diffraction factor in one direction while increasing it in the other, enabling better focusing and homogenization by using cylindrical lens arrays to rotate and reflect partial beams, thereby achieving a 'top hat' intensity distribution and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser radiation with high diffraction index is focused directly, then focusing ability is poor, but beam quality deteriorates and interference issues occur during superimposition
Solution Approach 1:
The laser beam is divided into multiple partial beams using beam splitting means, where each partial beam has a reduced diffraction index. This segmentation allows each partial beam to be focused more effectively while reducing interference effects during superimposition in the working plane.
Solution Approach 2:
Beam transformation means are used to exchange the diffraction indices between two perpendicular directions. By rotating and reflecting partial beams, the diffraction index in the focusing direction is reduced while the diffraction index in the perpendicular direction is increased, enabling effective line-like focusing.
2Manufacturing precision
If the number of partial beams is increased for better homogenization, then homogeneity improves, but high-frequency oscillations occur due to interference
Solution Approach 1:
The diffraction indices of partial beams are exchanged and spatial coherence is reduced before the superimposition in the working plane. This preliminary transformation of beam properties prevents the occurrence of high-frequency interference oscillations that would otherwise occur when multiple partial beams are superimposed.
3Manufacturing precision
If diffraction index is reduced in one direction for better focusing, then focusing precision improves, but diffraction index increases in perpendicular direction
Solution Approach 1:
The beam transformation means are configured to selectively exchange diffraction indices in specific directions. Cylindrical lens arrays with axes at 45° to the beam direction transform the beam properties locally in each direction, reducing diffraction index in the focusing direction while increasing it in the perpendicular direction, achieving direction-dependent beam control.
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 improved focusing with a very small beam waist in one direction and enhanced homogeneity in the longitudinal direction, reducing spatial coherence and minimizing interference effects, enabling the generation of a thin line with a defined intensity profile and allowing for the use of more lenses in homogenization without high-frequency oscillations.
Implementation Method 1
the beam transformation means are designed in such a way that they transform the laser radiation or partial beams of the laser radiation emitted by the laser light source in such a way that the diffraction factor increases with regard to the first direction and that the diffraction factor with regard to the second direction is reduced
Implementation Method 2
using cylindrical lens arrays to rotate and reflect partial beams
Implementation Method 3
the diffraction factor with regard to the second direction is reduced. The beam transformation means can transform the laser radiation or partial beams of the laser radiation in such a way that the diffraction index and/or the spatial coherence properties with regard to the first direction of the laser radiation or each of the partial beams is or will be exchanged with the diffraction index and/or the spatial coherence properties with regard to the second direction
Data Source
Figure 1~7
Figure 2a~3d
Figure 4a~5b
AI summary
Apparatus for beam shaping, in particular for producing a linear intensity distribution (28) in a working plane, comprising a laser light source (1) which can emit a multimode laser radiation (8) where both the beam quality factor (Mx 2)