Fig. 8
From: Improvement of the optical properties after surface error correction of aluminium mirror surfaces
a Reflectivity in the visible spectral range of the initial aluminium surface, after RIBE machining with nitrogen operating gas and subsequent RIBE finishing with oxygen operating gas with 1x, 3x, 10x and 20x repetitions. The measurements were repeated after about 1 year. The resulting measurements (dotted lines) are additionally shown in b) compared to the measurements performed on the freshly prepared surfaces (solid lines).