化学刻蚀的光学元件面形修复

采用化学加工方法对光学元器件进行面形加工,可以避免传统的抛光工艺带来的亚表面缺陷和表面污染。实验中利用Marangoni界面效应有效控制化学液的驻留时间和驻留面积,并通过数控系统实现编程控制加工,进行了面形修复实验,利用轮廓仪测量了加工前后的表面粗糙度。结果表明,采用拼接小去除量多次加工的方法,有效地降低了面形误差,面形值由1.32 λ(λ=632 nm)减少到0.66 λ,粗糙度基本维持不变。利用此实验装置使基片面形得到修复,避免了传统加工方式带来的亚表面缺陷等问题,有利于强激光系统的使用。

Form error of optical surface repaired by wet-etch figuring

A wet-etch figuring method is presented to repair the form error of optical surface to avoid the subsurface damage and surface pollution caused by traditional polishing technology. The Marangoni effect is used to control the dwell time and dwell area of chemical solvent,and the optical surface is repaired by program control of a digital system. The surface roughness of the optical surface before and after processing is measured by a profilometer. Experimental results show that the form error of the optical surface can be decrease from 1.22 λ(λ=632 nm) to 0.66 λ by the method in many wet-etch and a little wipe off surface figuring,but the optic surface roughness is invariable in test.The results also indicate that the method can improve the laser threshold of optical element.