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Micro vs. Macro

Micro vs. Macro

Most Schäfter+Kirchhoff Laser Modules are available as two different types: as Micro or as Macro Lasers. These lasers have in common their basic optical features like e.g. fan angle or line length. They are also available with the same laser diodes.
But they differ in
  • Laser line width or spot diameter
  • Rayleigh range/depth of foucs
  • Laser Power
Please note that there is a fixed relationship between line width/spot diameter, wavelength and Rayleigh range/depth of focus. A small line width automatically leads to a small Rayleigh range.
The general rule of thumb is: If you want a small laser line you will probably need a Micro Laser Generator. If you want a large depth of focus you are probably looking for a Macro Laser Generator.
In order to find the correct choice, please use the Product Configurator.

Micro Laser Modules

Micro Line intensity profile
Micro Line intensity profile

Brief insight

  • Small laser line widths or small laser spots
  • High power density in the focal plane
  • Gaussian intensity profile across the laser line or laser spot

Intensity Profile

Laser Micro Line or Micro Focus Generators are designed to produce lines with small line width or spots with small spot diameters. They have a small depth of focus (in this case the depth of focus is the Rayleigh range).

They have a high power density in the focus and a Gaussian intensity profile across the laser line/spot. With larger distance from the working distance A the power density decreases strongly while the line width/focus spot size strongly increases.

Rayleigh range
Rayleigh range

Rayleigh range

For a laser line with line width B (at the 13.5 % level) and wavelength λ, the depth of focus is defined as the Rayleigh range 2zR

{!{!{2z_R=(\pi B^2)/2\lambda}!}!}

For laser spots the line width B is replaced by the spot diameter Ø at the 13.5%-level. L is also replaced with the corresponding daimeter Ø.

Macro Laser Modules

Macro Line intensity profile
Macro Line intensity profile

Brief insight

  • Larger, almost constant laser line widths or spot sizes with lower power density
  • Extended depth of focus (7 to 35-times greater )
  • Approx. Gaussian intensity profile across the laser line or laser spot

Intensity Profile

Laser Macro Line or Macro Focus Generators are designed to generate laser lines/spots with an extended depth of focus. Within the depth of the focus range, the intensity profile across the laser line is approximately Gaussian and the side lobes caused by diffraction remain below the 13.5% intensity level.

To get a better idea some examples:

  • For a particular line width B or spot diameter Ø, the depth of focus of a Macro Line/Spot is almost twice that of the equivalent micro line/spot.
  • At the same working distance A, Macro Lines/Spots are 2 to 5-times wider and have a depth of focus 7 to 35- times larger than the equivalent micro line. The output power of a Laser Macro Line/Focus generator is gene­rally 50–60% smaller than that of a laser Micro Line/Focus Generator.
Depth of focus
Depth of focus

Depth of Focus

For a laser line with line width B (at the 13.5 %-level) and wavelength λ, the depth of focus 2zM is defined as:

{!{!{2z_M=1.75(\pi B^2)/2\lambda}!}!}

For laser spots the line width B is replaced by the spot diameter Ø at the 13.5%-level. L is also replaced with the corresponding daimeter Ø.