The measurement of laser beam parameters

Measurement of beam parameters can be made by using the total beam, or by sampling a known factor of the beam. Measurement of the total beam is the simplest technique but has the disadvantage that measurements are not available while material processing is in progress. Three methods of sampling part of the beam, usually a few per cent, are described. As a small sample of the beam is monitored, techniques with lower power capabilities can be used. All three provide the advantages of monitoring the beam while it is at the workstation, but can reduce the accuracy of measurement because of uncertainties in the fraction of the beam sampled. Each of the three methods has additional disadvantages.