Patent ID: 7291805

Claim:
A system for applying a laser beam to work pieces, comprising: a laser system producing an output beam; target delivery optics arranged to deliver said output beam to a target work piece; a relay telescope having a telescope focal point in a beam path between the laser system and the target delivery optics which relays an image between an image location near an output of the laser system and an image location near said target delivery optics; and a baffle including an opening at the telescope focal point large enough to easily pass the output beam propagating to the target, and small enough to block off angle and out of focus back reflections from the target delivery optics, wherein said laser system includes: a gain medium; a polarization rotator; a passive polarizer; a plurality of reflectors configured to define an optical path through the gain medium, the passive polarizer, and the polarization rotator; a phase conjugator configured to receive a beam from the optical path after the pulse has proceeded one or more transits through the optical path, the phase conjugator further configured to return the beam with reversed phase to the optical path to proceed an equal number of transits of the optical path in an opposite direction before exiting the optical path at said passive polarizer; and an intra-cavity relay telescope having a telescope focal point, between the gain medium and the passive polarizer, which is used for relaying images between the gain medium and a location near the output of the laser system.