BeamMonitor BM+

The PRIMES BeamMonitor BM+ is a measuring device for performing beam diagnostics on unfocused, continuous irradiation of CO2 and solid-state lasers with higher outputs.

With the BeamMonitor BM+, the user can quickly and reliably measure the beam parameters, such as the spacial power density distribution. Analyzing and documenting the laser parameters makes it possible to optimize the processing procedure or identify an incorrect beam position or incorrect lens alignment.



In practice, laser beams are “customized” for specific areas of application using telescopes and adaptive lenses. When this happens, the beam diameter as well as the divergence are changed dynamically. This makes it possible to change the focus dimensions or shift the focus position toward the laser beam axis in systems for laser cutting or laser welding. Here the focus is on “penetration” through the material surface and it is “pushed into” the material for the actual cutting process.

During laser welding, dynamic adjustments of the laser beam make it possible to cut with one setting and weld with another.

The BM+ is also suitable for use in the field of quality assurance or laser approval: Deterioration on laser lenses is one of the main causes of problems in laser material processing that can reduce the quality of the processing results considerably.

Diodes and other solid-state lasers are checked in the collimated range and can, for example, be assessed with relatively little effort.



  • A rotating measuring tip gathers measurements of the laser beam at points. The mirror holder is also moved linearly through the beam in order to measure the entire beam profile. One partial beam is moved to the detector at a time and measured in this way. The incident signal is digitized and transferred to the analysis unit. The 16-bit A/D transformer is used and a resolution of up to 1024 x 1024 pixels facilitate exact analysis of even the smallest disturbances in the raw beam.

    The device was developed for use in industrial production environments and can be used in any orientation.

    The software has the following standard functions:

    • Measurements: Single and series measurements, monitor operation, and measurement of the temporal development (Linescan)
    • False colors, plane analysis, tabular and graphic display of the numerical results
    • In PRIMES format .lpf as well as CSV and export graphic

    ­During the measurement, the entire beam leaves the BeamMonitor BM+ again. It then has to be absorbed as thoroughly and safely as possible. The PowerMonitor or one of the other PRIMES beam absorbers are examples of equipment optimally suited for this activity.

    Measured Beam Parameters:

    • Beam position
    • Beam dimensions
    • Beam symmetry
    • Power density distribution


The new PRIMES LaserDiagnosticsSoftware (LDS) can be used as a graphic interface for operating the BeamMonitor BM+. This software contains a wide variety of tools for analysis, display, and preparation of measurement data, including a report function. Data is communicated via an Ethernet connection.

Models and options

  • Depending on the beam measurements, a PRIMES BeamMonitor BM+ can be used with an aperture of 60 or 100 mm. Here the BeamMonitor BM+ 60 and the BeamMonitor BM+ 100 are available for CO2 or NIR laser.

    As a rule for dimensioning, the aperture should be at least 1.4 times the laser beam diameter. This ensures that intensities on the edges do not come in contact with the casing and heat it up and that the measuring range is not limited, which would distort the measurement result.