A Simple Interferometer for the Analysis of Terahertz Sources and Detectors

The design and performance of a simple and compact far-infrared Fourier transform spectrometer is described. The spectrometer works as a Michelson interferometer without a beam splitter, and uses a Golay cell or a pyroelectric sensor for detection. 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 terahertz emitters, as well as different terahertz detectors.