A simple interferometer for the characterization of sources at terahertz frequencies

The design and performance of a simple and compact far-infrared Fourier-transform spectrometer for the characterization of sources is described. The spectrometer works as a Michelson interferometer without a beam splitter and employs a Golay cell or a pyroelectric detector. A pair of flat lamellar mirrors with a computer-controlled displacement introduces a precisely defined phase difference between two parallel beams of nearly equal radiated power. The interferometer is intended for operation at frequencies between 0.1 and 3 THz with a frequency resolution of 6 GHz, and is used to characterize both continuous-wave and pulsed sources.