Continuous Wave Multimode Amplitude THz Spectroscopy

THz spectroscopy with continuous wave lasers is typically based on the frequency tuning of the lasers. This process is rather slow, and some systems require additional sophisticated postprocessing. We propose a multimode system without postprocessing requirements to reduce measurement time. For this, we use a modulation scheme with multiple laser sources to enable snapshot amplitude THz spectroscopy. As the detection is performed with a Schottky barrier diode the scheme is very fast but discards phase information. This approach makes amplitude THz spectroscopy possible without frequency tuning or any moving mechanical parts.