Figuring of optical aluminium devices by reactive ion beam etching

Abstract

Ion beam figuring (IBF) is an established method in high-end surface manufacturing. However, the direct processing of desired materials as standard Al alloys (e.g. Al6061)fails, since the surface roughness increases drastically as a result of inhomogeneous etching due to structural, crystallographic and chemical irregularities inside the material matrix. As an alternative figuring technology reactive ion-beam etching (RIBE) is a promising route. RIBE provides the direct machining of Al alloys while preserving the surface roughness almostin its initial state. The RIBE process with nitrogengasis focused more detailedin this study.