SELF-COMPENSATING, ALL-REFLECTION INTERFEROMETER

A grating interferometer that uses all-reflecting optical components has been developed for operation in the extreme and far UV. The instrument uses a V-groove, ruled grating as its beam splitter and has no moving parts. A self-compensating optical design is employed that makes it tolerant to small misadjustments of optical alignments and convenient for space-flight applications. The instrument described here uses a 600-groove/mm plane diffraction grating that operates in the second order and obtains a resolving power of approximately 100,000 at 1216 angstrom.