论文信息 - High Resolution Spectroscopy with a Quantum Cascade Laser at 2.5 THz

High Resolution Spectroscopy with a Quantum Cascade Laser at 2.5 THz

The quantum cascade laser (QCL) is a powerful, narrow linewidth, and continuous wave source of terahertz radiation. We have characterized a 23 THz distributed feedback QCL with respect to linevvidth and frequency tunability. Both were found to be sufficiently good for high resolution gas phase spectroscopy. The QCL was implemented in a spectrometer for high resolution gas phase spectroscopy where the absolute frequency of the laser was determined by mixing its radiation with the radiation of a 2.5 THz optically pumped gas laser. The absolute frequency as well as the pressure broadening of a rotational transition of methanol at 2.519 THz was measured. The results demonstrate that THz QCLs are well suited for either direct absorption or heterodyne high resolution spectroscopy.

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