ARTIFICIAL QUARTZ MEMBER, OPTICAL ELEMENT, OPTICAL SYSTEM, PROJECTION ALIGNER, AND METHOD FOR SELECTING ARTIFICIAL QUARTZ MEMBER

摘要

PROBLEM TO BE SOLVED: To provide an artificial quartz member whose transmission properties hardly deteriorate even when it is repeatedly irradiated with high-output, short-pulse laser beam for a long period of time.

SOLUTION: An optical element is obtained by using the artificial quartz member characterized in that lowering of the refractive index of a normal light ray 32 or abnormal light ray 33, generated at an irradiated part, is ≤50 ppm when the member is irradiated with 5.0×107pulses of ArF eximer laser beam having a fluence of 500 mJ/cm2.

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