Multiorder rotating grating interferometer.
A multichannel interferometer that uses a rotating grating to both disperse and Doppler shift an incident far-infrared laser beam is described. The laser beam is diffracted into a fan array of many (~ 10) beams that can be directed to probe the plasma along distinct chords. The phase-shift information is multiplexed in the frequency domain so that a single detector suffices to sense the recombined probing beams.
Howard
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