Figuring by multilayer deposition: 
a new technique for producing ultraprecision optics

C. Tarrio, C. J. Evans, T. B. Lucatorto, and C. W. Clark

National Institute of Standards and Technology
Gaithersburg  MD  20899

E. Spiller

IBM Research, Yorktown Heights NY 10549

The development of multilayer reflective EUV optics has produced a capability
for the deposition of thin films having subnanometer roughness and thickness
errors.  We have begun to apply this capability to correct small figure errors
in optical components.  By deposition of a corrective Co/C multilayer through
an appropriately designed mask, we have reduced the radial errors in a test
optic by an order of magnitude without adding any roughness to the surface.
We will discuss present limitations of the technique and the extension to
general 2-D corrections of a surface.