A Simplified Method for Measuring the Surface Figure of Off-Axis, Aspheric Mirrors

With the advent of new technologies such as diamond turning, ductile grinding, and computer-controlled polishing, the fabrication of complex off-axis, aspheric optical components has become a routine method for the production of ultra-high resolution optical systems for multispectral applications. However, the field of metrology with respect to such components can not be said to have progressed as rapidly. In fact, the metrology of an aspheric mirror can oftentimes become much more of a burden than the surface fabrication itself. In most cases, the surface figure is more difficult to determine than the surface finish. This presentation concentrates on the issue of surface figure measurement.