COIL用薄膜90°位相延迟高反射镜的研制

Fabrication of HR mirror with 90° phase retardance in COIL resonator

随着氧碘化学激光器(COIL)输出功率的不断提高,传统的膜系设计已不能满足要求.在倍频膜系的设计基础上,优化设计出了激光45°入射时对1 315 nm和632.8 nm双波长高反(HR)并在1 315 nm处具有90°位相延迟的高反射镜,其基底材料为融石英,高折射率材料为ZrO2,低折射率材料为SiO2.然后,采用电子束蒸发手段制备了口径为200mm的高反射位相延迟镜.最后对该延迟镜的性能进行了测试,结果表明:对632.8 nm波长的反射率大于等于95.0%,对1 315 nm波长的反射率大于等于99.8%,位相延迟在90.235°～95.586°范围内.

With the continuous increase of COIL output power, the conventional HR film stack gradually can't satisfy the practical requirements. In this paper, on the base of multiple frequency film stack, a φ200 mm HR phase retardance mirror at 45° incidence is designed and fabricated by e-beam evaporation equipment. The substrate is fused silica, and the high and low refractive index materials are ZrO2 and SiO2 respectively. The measured results show that the reflectivity at 632.8 nm is no less than 95.0%, the reflectivity at 1315 nm is no less than 99.8%, and phase retardance at 1315 nm is 90.235°-95.586°.