Unusual aspheric optics: what is possible in IR optics manufacture?

The state-of-the-art in infrared optics can be looked at in terms of size, quality, material or complexity. Itek has recently completed the manufacture of an optical component that presented most of these challenging requirements to the designer, the manufacturing group and the test engineer. We believe that the combination of severe asphericity, test complexity and lightweight construction are representative of the most difficult optics producible today. The mirror is a convex asphere, with only bilateral symmetry, a departure from the nearest sphere of 178 micrometers , and a maximum slope departure of 4.0 micrometers per mm. Testing required a combination of null correctors and binary optics, with extremely tight alignment tolerances. Surfacing was accomplished with small tools and computer controlled optical surfacing.