FULL-SURFACE INTERFEROMETRIC TESTING OF GRAZING INCIDENCE MIRRORS

THE NEED EXISTS FOR A METHOD TO CHARACTERIZE AND QUALIFY THE NECESSARY OFF-AXIS ASPERHICAL MIRROR TECHNOLOGY FOR USE IN WEAPON POINTING, BEAM CONTROL, AND BEAM PROPAGATION THROUGH SEVERAL ENVIRONMENTS AND COUNTERMEASURES. CURRENTLY, NO INSTRUMENT EXISTS THAT CAN MEASURE BOTH THE FULL SURFACE FIGURE AS WELL AS THE SURFACE ROUGHNESS. IN THIS INVESTIGATION, FEASIBILITY IS BEING DETERMINED OF A FULL-SURFACE INTERFEROMETRIC APPROACH CAPABLE OF TESTING GRAZING INCIDENCE MIRRORS. THIS METHOD, BASED ON THE USE OF NORMAL INCIDENCE, SUB-APERTURE INTERFEROMETRY AND POLARIZATION SHARING INTERFEROMETRY, SURMOUNTS MANY OF THE PROBLEMS ENCOUNTERED BY OTHER TECHNIQUES. THE SYSTEM INVOLVES THREE SEQUENTIAL OPERATIONS: SUB-APERTURE SLOPE MEASUREMENT, WAVEFRONT INTEGRATION AND SURFACE PROFILE SYNTHESIS. WHEN SUCCESSFULLY DEVELOPED, THE RESULTING INSTRUMENT WOULD FIND APPLICATION IN X-RAY AND UV HIGH RESOLUTION LITHOGRAPHY, MEDICAL DIAGNOSTIC IMAGING, BASIC RESEARCH IMAGING IN ASTRONOMY, PHYSICS, AND MICROBIOLOGY.