The easiest
way to characterize how well a real world
laser beam can be collimated or focused is
through the use of the beam propagation
factor (M2). Unfortunately, M2 is not readily
measured using traditional laser beam diagnostic instruments such as power meters
or beam profilers. This whitepaper reviews
how M2 is used to calculate actual (rather
than theoretical) laser beam properties, and
then presents a practical instrument that enables rapid m2 measurement.