Terahertz time-domain spectroscopy with continuous coverage of the entire terahertz range

Using gases as the emitter and detector media in a THz system allows for good phase matching over the full terahertz range (0.3 to 10 THz), without interruptions from crystal phonon modes or other instrument artifacts. A heterodyne technique facilitates coherent measurement of the electric field waveform, enabling this technique to be used for time-resolved spectroscopy in which a single measurement can continuously cover the entire terahertz region of the electromagnetic spectrum.