Stressed Mirror Polishing: A Technique for Making Non Axisymmetric Mirrors

We describe a new technique for the fabrication of non axisymmetric mirrors and an experimental demonstration of the technique. The technique takes advantage of the ease of polishing spheres by applying appropriate external stresses to elastically deform the desired mirror shape into a sphere. The sphere is polished into the blank, and upon release of the external forces, the mirror springs back to the desired shape. We have tested this method by making an off axis paraboloid requiring 10pm deflections. The final mirror was paraboloidal to 0.03μm.