THz Spectroscopy by Frequency-Tuning Monochromatic THz Source: From Single Species to Gas Mixtures

Different gases have been successfully fingerprinted on the basis of the distinct transition frequencies measured by frequency tuning a THz source developed by us. Our further analysis illustrates that one can reliably separate isotopologues by measuring and comparing their rotational constants. Based on our investigation of the N
₂
O isotopologues, 29 rotational transition peaks were identified for the first time. For the gas mixtures, preliminary results indicate that one can identify the components of chemical species and the corresponding concentrations. Based on our spectroscopic results, the tunable THz source may offer a viable approach in the identifications and detections of chemical species.