Patent ID: 8553311

Claim:
A method of controlling dynamic, rapid attenuation of a polarized output laser beam intensity uniformly across a spatial intensity profile of the output laser beam as it is switched between a first power intensity level and a second power intensity level, the first power intensity level being suitable for laser processing a workpiece, and the second power intensity level being sufficiently low so as not to affect the physical character of the workpiece, the method comprising: generating an input laser beam propagating along a first beam path portion of a beam path toward a target location on the workpiece; directing the input laser beam propagating along the first beam path portion to a galvanometer system including a rotatable shaft that rotates about a rotation axis positioned transversely of the first beam path portion, the rotatable shaft carrying an angle of light incidence-sensitive optical element including a planar optical film positioned to receive and produce from the input laser beam the polarized output laser beam that propagates along a second beam path portion of the beam path toward the target location on the workpiece, the spatial intensity profile of the polarized output laser beam varying as a function of an angle of incidence between the input laser beam and the planar optical film; applying to the galvanometer system a control signal produced by a processor to control rotation of the rotatable shaft and thereby angular positioning of the planar optical film; and providing shaft positioning information to which the processor responds to produce the control signal for angular positioning the planar optical film to change the angle of incidence between a first angle that establishes the first power intensity level suitable for laser processing the workpiece and a second angle that establishes the second power intensity level that does not affect the physical character of the workpiece, and thereby provide uniformly across the spatial intensity profile dynamic, rapid attenuation of the polarized output laser beam.