BeamMonitor Measuring device for the characteristics of the unfocused laser beam

• determination of beam width and beam position based on the measured power density distribution
• Intuitive grahical user interface
• High dynamic due to a 14 bit A/D
• Quartz-stabilized motor drive of the rotational axis
• Power range 100 W - 20 KW
• Power density range 100 W/cm2 - 10 kW/cm2 > 20kW
• Different apertures matched to the applications between 40 mm and 100 mm

Application

The laser beam is scanned with a rotating mirror So a small part of the beam is faded-out and directed to the detector.During the motion of the mirror the incoming signal is digitized and transmitted to acomputer. The position of the scanning track is changed by a linear motion in y-direction. The 12 bit A/D-converters and a resolution of 128x256 pixel enables an exact analysis of even small pertubations. operation laser-induced variations of the beam parameters cause a decrease of processing quality and velocity. The exact analysis of the true reason is ordinarily rather complicated, since other phenomena like variation of the focal position or the nozzle's adjustment have similar errors. At this point a detailed analysis of the 'raw' laser beam between outcoupler and focussing optics is a reliable method to detect variations of the beam diameter, bad mode-structure or wrong beam position.

With the BeamMonitor from PRIMES the customer gains the opportunity of quick and reliable diagnostics of the beam parameters. The BeamMonitor is a device to determine the spatial power density distribution of high power CO2- and Nd:YAG - Lasers.

The beam diameter and position are calculated from these data.

Technical description

The laser beam is scanned with a rotating mirror So a small part of the beam is faded-out and directed to the detector. During the motion of the mirror the incoming signal is digitized and transmitted to acomputer. The position of the scanning track is changed by a linear motion in y-direction. The 14 bit A/D- converters and a resolution of 128x256 pixel enables an exact analysis of even small pertubations.The device is designed for operation in rough industrial environments.

Control and presentation

Control is realized by different user specific solutions such as: graphical user interfaces in Microsoft WINDOWS™ availiable as well as a direct connection to a SPC. For interface to a PC or SPC, the built in RS485- interface is used.The software has the following features:

• Measurement parameters: beam radius (based on 86 % and 2nd moment calculation), beam position and power density calculated from a given power value in peak and 86 % - radius.
• Measuring modes: single and serial measurement, temporal development
• Presentation: Isometry, false color, contour lines and check of symmetry.