SELF-COMPENSATING, ALL-REFLECTION INTERFEROMETER

A grating interferometer that uses all-reflecting optical components h as been developed for operation in the extreme and far UV. The instrum ent uses a V-groove, ruled grating as its beam splitter and has no mov ing parts. A self-compensating optical design is employed that makes i t tolerant to small misadjustments of optical alignments and convenien t for space-flight applications. The instrument described here uses a 600-groove/mm plane diffraction grating that operates in the second or der and obtains a resolving power of approximately 100,000 at 1216 ang strom.