Patent ID: 7903351
Filing Date: 2011-03-08
Classification: G03F,H01S

Abstract:
1. A method of extending service lives of crystal optics that transmit concentrated laser beams comprising steps of generating a laser beam, transmitting the laser beam within an enclosed pathway through at least one crystal optic at a power density that progressively degrades transmissivity of the crystal optic with accumulating fluence, actively cooling the crystal optic to slow the progressive degradation in the transmissivity of the crystal optic with the accumulating fluence or to accommodate a higher power density without correspondingly increasing the progressive degradation in transmissivity, and limiting humidity within the enclosed pathway to avoid condensation of water vapor onto a transmitting region of the actively cooled crystal optic, wherein a coldest portion of the crystal optic within the transmitting region is cooled to a temperature above the freezing point of water and less than five degrees Celsius above the freezing point of water.