A Yb fiber laser pumped cw narrow-linewidth tunable mid-IR source based on a difference frequency generation (DFG) in a periodically poled LiNbO3 (PPLN) crystal for trace gas detection was demonstrated. A high power Yb fiber laser and a distributed feedback (DFB) laser diode were used as DFG pump sources. This source generated mid-IR at 3 microns with a powers of ~2.5 microW and a spectral linewidth of less than 30 MHz. A frequency tuning range of 300 GHz (10 cm-1) was obtained by varying the current and temperature of the DFB laser diode. A high-resolution NH3 absorption Doppler-broadened spectrum at 3295.4 cm-1 (3.0345 microns) was obtained at a cell pressure of 27 Pa from which a detection sensitivity of 24 ppm m was estimated.

中文翻译：

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基于差频产生的光纤激光器抽运中红外光源及其在氨气检测中的应用。

演示了一种Yb光纤激光泵浦的连续波窄线宽可调中红外光源，该光源基于在周期性极化的LiNbO3（PPLN）晶体中的差分频率生成（DFG），用于痕量气体检测。高功率Yb光纤激光器和分布式反馈（DFB）激光二极管用作DFG泵浦源。此源产生3微米的中红外，功率约为2.5微瓦，光谱线宽小于30 MHz。通过改变DFB激光二极管的电流和温度，可以获得300 GHz（10 cm-1）的频率调谐范围。在27 Pa的池压下获得了3295.4 cm-1（3.0345微米）的高分辨率NH3吸收多普勒增宽光谱，据此估计检测灵敏度为24 ppm m。