総説

炭酸ガスレーザー差周波型テラヘルツ光源と分子分光

A Terahertz Light Source Based on the Difference Frequency of Two CO₂ Lasers and Its Application to Molecular Spectroscopy

松島 房和
Fusakazu MATSUSHIMA

周波数精度を重視した分光研究を目的として，富山大学において10年来稼働させている炭酸ガスレーザー差周波型テラヘルツ分光計をとりあげ，分光計の原理や特長，これにより調べられた分子やイオンについて解説する。

A tunable light source in the terahertz region synthesized from two CO₂ lasers and a microwave source is introduced with its principles, features, and applications to high resolution spectroscopy. This light source, called TuFIR in short, covers the frequency range from about 0.5 to 6 THz. The accuracy of the synthesized frequency of about 30 kHz enables us to study the spectral lines in the terahertz region with high accuracy comparable to those of microwave spectoscopy. Examples of the spectroscopy of molecules, radicals, and molecular ions investigated with TuFIR spectrometer are shown.