AS-GROWN SINGLE CRYSTAL OF AN ALKALINE EARTH METAL FLUORIDE MANUFACTURED BY A SINGLE CRYSTALLINE PULLING METHOD

摘要

PURPOSE: An as-grown single crystal of an alkaline earth metal fluoride is provided to increase a diameter of the alkaline earth metal and to improve a light transmittance of the edge portion of the alkaline earth metal. CONSTITUTION: A single crystal of alkaline earth metal fluoride is in a grown state of the alkaline earth metal fluoride and is produced by a single crystal pulling method. The single crystal has a straight barrel part diameter of not less than 17cm. A light transmittance of the single crystal measured at a wavelength of 632.8 nm is not less than 80%. The main crystal growth plane of the single crystal is a {111} plane. The main crystal growth plane of the single crystal is a {100} plane. The straight barrel part has a length of not less than 5cm.