Two-wavelength oscillation from laser a cavity partially-inserted a cover glass etalon and its application to THz-wave generation

通过在紧凑型固体激光器和外腔半导体激光器腔中部分插入商用盖板玻璃标准具，我们观察到了不同的双波长振荡。双波长振荡的频率间隔相当于覆盖玻璃标准具自由光谱范围(FSR)的6倍。通过实验研究了双波长振荡的横模特性、振荡的时间稳定性和频率间隔的变化特性，证实了所构建的紧凑型双波长振荡激光器适用于太赫兹时域光谱分析系统的泵浦激光器。

We observed distinct two-wavelength oscillations from a compact solid-state laser and an external cavity semiconductor laser by partially-inserting a commercially available cover glass etalon into those laser cavities. The frequency interval of the two-wavelength oscillation corresponded to six times the free spectral range(FSR) of the cover glass etalon. It was confirmed that the constructed compact two-wavelength oscillation lasers were useful for a pump laser of a terahertz time-domain spectroscopy system by experimentally examining two-wavelength oscillations in terms of the characteristics of the transverse mode, the time stability of the oscillation, and the variable characteristics of the frequency interval.