Title: High Resolution Terahertz Spectroscopy with Quantum Cascade Lasers
Abstract: High resolution terahertz (THz) spectroscopy is a powerful analytical tool for laboratory purposes as well as for remote sensing in astronomy, planetary research, and Earth observation. THz quantum cascade lasers (QCLs) are promising sources for implementation into THz spectrometers, in particular at frequencies above 3 THz, which is the least explored portion of the THz region. One application of QCLs in THz spectroscopy is in absorption spectrometers, where they can replace less powerful and somewhat cumbersome sources based on frequency mixing with gas lasers. Another one is using a QCL as local oscillator in a heterodyne spectrometer for remote sensing. This article will review the state-of-the art in high resolution THz spectroscopy with QCLs.