[摘要]：A narrow-linewidth cw 5 mu m source based on difference frequency generation of a 1.3 mu m quantum dot external cavity diode laser and a cw Nd:YAG laser in periodically poled MgO : LiNbO3 has been developed and evaluated for spectroscopic applications. The source can be tuned to any frequency in the 5.09-5.13 mu m range with an output power up to 0.1mW, and in the 5.42-5.48 mu m range with sub-microwatt output. The output frequency is stabilized and its value determined by measuring the frequency of the two lasers with a remotely located frequency comb. A frequency instability of less than 4 kHz for long integration times and a linewidth smaller than 700 kHz were obtained. (C) 2012 Optical Society of America
