Plasma jet assisted polishing of fused silica freeform optics

Atmospheric pressure plasma jet machining technology not only provides a flexible and efficient way to generate and correct optical freeform surfaces made of fused silica, it can also be applied as a surface smoothing or polishing technique. Thermal plasma jet treatment leads to softening and redistribution of the material. An accurate temperature regime during the process is inevitable to achieve a uniformly smoothed surface. The possibilities for inȭprocess temperature control are demonstrated. Surface roughness values can be significantly reduced by a factor of 1000 depending on the initial roughness of the ground surface.