Development of a High-Resolution Spectrometer in the THz Region Based on Difference Frequency Generation of Two Infrared Lasers

(1)利用NH_3和CO_2激光器的差频产生太赫兹辐射<15>：我们研制了一台CO_2激光器，并对其进行了频率稳定。我们试图提高<15>NH_3激光器的功率，以提供更高的差频。(2)THz区分子跃迁频率的预测：利用TuFIR光谱仪，利用两束CO_2激光的差频，在1-5 THz区观测到XeH^+的转动跃迁。通过对甲酸甲酯（HCOOCH_3）的微波光谱的观测，确定了甲基扭转的势垒高度等分子参数。

(1) Generation of Terahertz Radiation Based on Difference Frequency between ^<15>NH_3 and CO_2 Lasers:We have constructed a CO_2 laser to generate terahertz radiation and stabilized its frequency. We tried to improve a ^<15>NH_3 laser in power in order to provide a higher difference frequency.(2) Prediction of Transition Frequencies of Molecule in the THz Region:Rotational transitions of XeH^+ have been observed in the 1-5 THz region with a TuFIR spectrometer based on difference frequency of two CO_2 lasers. Determined molecular parameters enabled us to predict frequencies of rotational transitions over 6 THz.The microwave spectrum of methyl formate (HCOOCH_3) has been observed to determine molecular parameters such as potential barrier height of the methyl torsion.