Design and manufacture of diffractive
optical elements

 

M-Shape intensity distribution for scanning applications

HOLO/ORís M-Shaper, is a diffractive optical elements (DOE) used to transform a Gaussian laser beam (or other) into a unique 2D M-shaped intensity profile, with sharp edges in a specific work plane.

Features
  • Round M-Shape output profile (before integration)
  • Uniform output intensity profile when integrated over a scanned line
  • Sharp beam edge
  • High efficiency
  • High power threshold
  • Wavelengths from UV to IR
  • Optional Ar/Ar coating
Applications
  • Laser materials processing:
    • welding
    • cutting
    • scribing
  • Strong weld seams (also in Plastics)

M-Shape Scanning Applications
Figure 1 - Simulated intensity profiles of diffractive M-Shaper laser spots (Without integration). Left fig.=Upper view, Right fig.=Side view.
The M-Shaper optical function is not possible by conventional reflective or refractive optical elements. It provides higher quality of the process & enables more flexibility in the system configuration. For example, it allows optimization of the intensity profile, and image size, without changing the laser, fiber cable and/or optic head.
In general, the intensity profile influences the heat distribution during laser material processing. The benefits of our optimized M-shaped intensity profile, in scanning applications (i.e., for the welding process) include:
  • Uniform exposure over the scanned line
  • Ensures a defined edge
  • Enables very strong weld seams

Design Considerations:

  • In principal, to get a flat-top scanning profile (as shown in Fig.3), optical designer needs to notice the following points:
    • Use a collimated laser beam with DOE
    • Place the DOE before the scanning head
    • Use a scanner lens (i.e. F-Theta lens) in order to achieve a well-focused spot at a certain distance, for all scanning angles, as shown in Fig.2.
    • Scan in straight lines

  • Energy distribution can be designed for any non-uniform distribution meeting the application's requirements
M-Shape Scanning Applications
Figure 2 - Schematic set-up and integrated (S) intensity profile across scan direction. Left=with M-Shaper,. Right=with flat-top beam shaper.
Scanning application Gaussian Vs. M-Shape
Figure 3 - Left picture: Gaussian intensity profile vs. M-Shaped profile, in scanning mode. Right picture: Top-Hat intensity profiles vs. M-Shaped profile.
   

Specifications:

Materials:Fused Silica, ZnSe
Wavelength range:193nm to 10.6um
Full angle:Large range of full angles
DOE design:2-level (binary) to 16-level
Diffraction efficiency:86% - 96%
Element size:Few mm to 100mm
Coating (optional):AR/AR Coating
Custom Design:Almost any size

Standard products

Part Number Wavelength (nm) Dimensions (mm) Beam size (mm) Working distance (mm) Depth of focus (DOF) [um] Material
EF-001-I-Y-A* 1064 25.4 13 25.4 450 FS
EF-002-I-Y-A* 1064 25.4 3 25 376 FS
EF-003-J-Y-A* 1030 25.4 12 25 650 @ n=1.7 FS
* lens f=25mm not included

For more information: holoor@holoor.co.il

@Copyright 2017, Holo/Or Ltd. P.O.B 1051, Rehovot, 7611001 Israel
Phone: +972-89409687/8, Fax: +972-89409606

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