Ion & plasma processes

Ion & plasma processes at CSL

 

Ion Beam Figuring

The Ion Beam Figuring (IBF) technique is used to improve the final shape of optics. A noble gas ion beam is scanned over the optical surfaces in order to remove the undesired thickness of material. The scan velocity is computed on basis of the initial surface errors map (typically measured by interferometry) and the etching profile of the ion beam.

This technique allows reducing the initial surface errors from hundreds of nm rms to a few nm rms.

Surface errors have been reduced from 190 nm to 2 nm rms after IBF treatment on this NiP coated mirror (Sentinel  4, done on behalf of AMOS)

Ion Beam Texturing

Beside the figure improvement with IBF, we focus also on the roughness evolution of several materials under ion beam sputtering [11, 22, 38]. Driving the ion beam sputtering of some materials in specific conditions allow generating some repetitive nano or micro-structures on large surfaces.

Plasma etching

Reactive Plasma Beam Etching (RPBE) is used to transfer micro-structures into a monolithic substrate. RPBE is widely used in the fabrication of micro-optical elements such as diffraction grating, phase plates, inserts …

Reactive Plasma Beam Etching