New optical method for measuring small-angle rotations.

To measure small-angle rotations, the two mirrors of a Michelson interferometer are replaced by right-angle prisms. Rotation of the latter shifts the interference pattern. Measurement of that shift gives, after calibration, the rotation. The experimental setup is insensitive to vibrations, provides good linearity between +5 degrees and -5 degrees , and has a resolution of 10(-4) deg.