Diffraction grating-based tool for spectral characterization of THz beams

The spectroscopic tool for the analysis of narrow-band THz beams is proposed. It is based on a single diffraction grating and one moving element (rotary or transitional stage). Two configurations - transmissive and reflective - are analyzed and compared. Compared with commercially available spectroscopes, the setup is simple, cost-effective, and easily adapted to the given conditions. The obtained experimental error of the frequency prediction was as low as 0.19%.