| 摘要 |
<p>The present invention relates to a calcium fluoride optical device in which laser durability is improved. The calcium fluoride optical device is used for the transmission of electromagnetic radiation under 250 nm. The optical device is made of; CaF<sub>2</sub> which is main ingredients; Mg having amounts of 13 to 20 ppm range, Ce which is lower than 0.5 ppm, and Mn. A doped crystal and the optical device which is made of the crystal are exposed higher than 2.8 MRads of Y radiation and have a transmission loss rate of 515/380 nm under 0.3. The doped crystal and the optical device which is made of the crystal show largely improved lifetime such as an ALDT test with at least pulses of billion times. [Reference numerals] (AA) Transmission loss rate (R=Δ515/Δ380); (BB) Standard; (CC) Approximate Trend Line; (DD) Measured Mg content (ppm)</p> |
