Characterization and Use of a 1.3–1.5 THz Multiplier Chain for Molecular Spectroscopy

Modular fixed-tuned wide-bandwidth multiplier sources for THz generation have enabled and greatly simplified high sensitivity molecular spectroscopic measurements. However, the multiplied sources must be carefully characterized. Characterization requires band-wide measurements of power levels and harmonic content, as well as understanding any spurious behavior. Also, simple bias schemes, and acceptable input power levels that eliminate spurious behavior, support long term reliability, and result in repeatable performance are critical in spectroscopic applications. The fully characterized source may then be useful for both narrow-band high sensitivity integrations, or for band-wide surveys. Coupling the source with various gas-handling systems enables valuable new spectroscopic measurements that improve upon techniques such as Tunable Far-Infrared spectroscopy, Laser-sideband spectroscopy, and photomixer based spectroscopy.