BeamMaster Laser Beam Profiler

A high resolution scanning knife-edge laser beam profiler for CW lasers

Coherent's BeamMaster™ is a high precision tool for characterising the beam shape, power and position of CW laser beams in the wavelength range from 190 to 1800nm. BeamMaster accomodates lasers with focussed beam sizes from 3µm to 9mm with 0.1µm resolution, some 100 times greater than for a typical CCD-based profiler.

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The BeamMaster Family

The BeamMaster family is made up of five versions, two based upon silicon detectors for the wavelength range 190-1100nm, and three based upon InGaAs detectors for the IR band from 800-1800nm.

At the heart of each BeamMaster profiler is a photodetector placed behind a rotating drum in which are cut between 3 and 7 slits (knife edges) through which the laser beam propagates. Each slit is orientated at different angles, meaning that in one rotation of the drum, the laser beam is scanned through multiple axes. The greater the number of slits, the higher the measurement resolution and accuracy. The two silicon based profilers are available with either 3 or 7 slits, and sensor apertures of 5 or 9mm respectively. Similarly, the InGaAs models come with either 3 or 7 knife edges with apertures of 3mm for the 3 axis model or 3 or 5mm for the 7 axis profiler.

Measurement & Display Capabilities

On each rotation of the drum, BeamMaster scans the beam through each of the seven knife edges (three knife edges with BM-3). This data is processed to yield beam power, position and profile information. This data can be displayed every rotation, strip charted, sent to file or to the RS232 port. Two orthogonal profiles can be displayed at the same time and the beam widths can be digitally displayed for any of three user-chosen clip levels. A Gaussian fit profile can be overlaid on any chosen measurement profile and the fit and correlation parameters displayed.

BeamMaster displays beam profiles as either 2D or psuedo 3D images. The BM-7 profiler with 7 knife edges possesses the resolution necessary to reconstruct the complex beam shape associated with (for example) diode lasers, whereas the 3-axis models (BM-3) can be used for accurate measurements with near-Gaussian beams.

The beam centroid position can be continuously monitored relative to the center of the sensor area, along with the beam shape, ellipticity (major and minor axes) and angular orientation.

BeamMaster also records the power in the beam. A test range can be defined and an audio alarm can be activated if the beam power strays outside of specified limits.

The BeamMaster software displays beam size, position and power in analogue, digital and strip chart formats. Data can also be logged to file in real time for post processing or test report generation. Pass / Fail type testing can be performed based upon user-defined criteria.

Accessories

An optional mount is available to enable rotation of the BeamMaster sensor head about its optical axis. This mount has a 360° calibrated scale with a locking screw. A C-mount adapter plate is available to allow attachment of any C-Mount, threaded optical accessory, such as a Coherent BCUBE high-power attenuator pick-off optic (for further details, see the Beam Diagnostics Accessories page) A fiber-optic adapter plate is also available to allow attachment of an optical fibre fitted with an FC connector. 

Specifications & Ordering Information