表面改性非球面碳化硅反射镜的加工

为了获得高质量光学表面的非球面碳化硅(SiC)反射镜，对碳化硅反射镜表面改性技术以及离子束辅助沉积(IBAD)Si改性后的非球面碳化硅反射镜的加工技术进行研究。首先，简要介绍了碳化硅反射镜表面改性技术以及本文所采用的离子束辅助沉积(IBAD)Si的改性方法。然后，通过采用氧化铈、氧化铝以及二氧化硅等各种抛光液对离子束辅助沉积(IBAD)Si的碳化硅样片进行抛光试验。试验结果表明氧化铈抛光液的抛光效率较高，使用二氧化硅抛光液抛光后的样片表面质量最好。最后，在上述实验的基础上，采用计算机控制光学表面成型（CCOS）技术对尺寸为650mm×200mm的表面改性离轴非球面碳化硅(SiC)反射镜进行加工，最终的检测结果表明离轴非球面碳化硅(SiC)反射镜实际使用口径内的面形精度（RMS值）优于λ/50（λ=0.6328μm），表面粗糙度优于1nm（Rq值），满足设计技术指标的要求。

Fabrication of surface modification aspheric SiC mirror

In order to manufacture fine optical performance surface of aspheric silicon carbide(SiC) mirror, the technology of surface modification for SiC mirror is presented, and the technology of fabrication of surface modification aspheric SiC mirror is studied. First, ways of surface modification on SiC mirrors are introduced, and especially the technology of ion beam assisted deposition(IBAD)-Si on SiC mirror surface is emphasized.Then several polishing agents, such as CeO2, Al2O3 and SiO2, are used in experiments for polishing SiC samples with surfaces modification. It is verified that high polishing efficiency is acquired in experiment with polishing agent of CeO2, and the best optical surface is fabricated in experiment with polishing agent of SiO2. Finally, on the basis of experiments, 650mm×200mm off-axis aspheric SiC mirror with surface modification is manufactured by the technology of computer-controlled optical surfacing. The testing results indicate that the surface accuracy of the aspheric SiC mirror with surface modification is better than λ/50(RMS)（λ=0.6328μm）, and surface roughness is less than 1nm(RMS).