The University of Dayton has designed and built an Infrared Ellipsometer/ Reflectometer (E/R) to characterize curved surfaces in support of the ALPHA Laser Program. The instrument is tunable in wavelength and angle of incidence, is remotely controlled by a dedicated microcomputer, is positioned and scanned by a six-degree-of-freedom translation stage, and makes simultaneous measurements of Rp, Rs, Ψ, and Δ.

A return path configuration was chosen to provide the versatility necessary for the variety of curved surfaces to be used in the ALPHA laser. This E/R is capable of measuring Rp and Rs to 0.1% accuracy and Delta to better than 0.1° accuracy on curved surfaces to 1.0 centimeter radius of curvature.

The optical design and theory of operation as well as automatic alignment and focusing features are discussed. Data taken with this instrument are presented.