M?¨C Beam Propagation Analysis
M?, or Beam Propagation Ratio, is a value that indicates how close a laser is to being a single mode TEM00 beam, which in turn determines how small a beam waist can be focused. For the perfect Gaussian TEM00 condition the M? equals 1. M? cannot be determined from a single beam profile measurement. The ISO/DIS 11146 requires that M? be calculated from a series of measurements. M? is measured on real beams by focusing the beam with a fixed position lens of known focal length, and then measuring the characteristics of the artificially created beam waist and divergence. We have a number of solutions for the measurement of M? ranging from simple manual processes to fully automated dedicated instruments, depending on the frequency of the need to measure M? of lasers and laser systems.