Multichannel interferometry using high-order rotating diffraction gratings

Abstract

We report the successful construction and operation of a far-infrared (337 μm) interferometer based on a multiple-order diffraction grating wheel. On reflection from the wheel circumference, the incident laser beam is diffracted into a number (∼12) of approximately equal intensity high-order beams. Since the Doppler offset of the beams is proportional to the diffraction order, information encoded by the spatially distinct beams is multiplexed in the frequency domain. This allows simultaneous multichannel phase shift information to be obtained using only a single detector. Show more