2m大口径RB-SiC反射镜的磁控溅射改性

为了消除RB-SiC反射镜直接抛光后表面存在的微观缺陷,降低抛光后表面的粗糙度,提高表面质量,针对大口径SiC的特性,选择Si作为改性材料,利用磁控溅射技术对2m量级RB-SiC基底进行了表面改性。在自主研发的Φ3.2m的磁控溅射镀膜机上进行基底镀膜,利用计算机控制光学成型法对SiC基底进行了抛光改性。实验结果表明,改性层厚度达到15μm;在直径2.04m范围内,膜层厚度均匀性优于±2.5%;表面粗糙度由直接抛光的5.64nm(RMS)降低到0.78nm。由此说明磁控溅射技术能够用于大口径RB-SiC基底的表面改性,并且改性后大口径RB-SiC的性能可以满足高质量光学系统的要求。

Surface modification of 2 m RB-SiC substrate by magnetron sputtering

In order to eliminate the surface microdefect after the direct polishing of RB-SiC substrate, reduce the surface roughness and increase the surface quality, Si was selected as the modified material based on the features of large aperture SiC, where a 2 m-level RB-SiC substrate was modificated by using the magnetron sputtering technology. The silicon film was deposited by a developed Φ3.2 m magnetron sputtering coating machine, and the SiC substrate was polished and modificated based on the computer control optical molding method. The result indicates that the thickness of modified level reaches 15 μm; the thickness uniformity of the film level is better than ±2.5% within the diameter of 2.04 m; the surface roughness decreases from 5.64 nm (RMS) to 0.78 nm. Therefore a the magnetron sputtering technology can be used in the surface modification of the large aperture RB-SiC, and the performance of the modificated RB-SiC substrate can meet the requirements of high-quality optical systems.