摘要 |
A laser apparatus includes a laser for emitting a laser beam which is reflected from a primary mirror through a primary lens in a primary optical path and focused at a primary spot. A portion of the laser beam leaks through a back face of the mirror and is directed through a reference lens and focused at a reference spot in a reference optical path. Angular wander of the laser beam on the primary mirror is corrected by measuring the lateral position of the reference spot and adjusting the primary optical path to decrease lateral wander of the primary spot.
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