【摘要】 基于非线性光学效应,采用差频发生技术(Difference frequency generation)和准相位匹配技术(Quasi-phase matching),在周期性极化的铌酸锂晶体(PPLN)中产生了中红外的可调谐激光源。泵浦光是一个功率为1W、调谐范围在770到870nm之间的连续可调谐钛宝石激光器。信号光是一个功率为1W、单频连续的Nd∶YAG激光器。当晶体的光栅周期为20μm、温度调谐范围内在室温到200℃之间时,能够产生2.8μm附近的、功率约为1～2μW的差频光源。基于这个光源,采用直接吸收光谱方法测量了实验室大气中的水汽(001←000)吸收带的吸收光谱。依据大气中水汽分子在8.5cm的吸收光程条件下的吸收光谱,成功地测量得到了大气中的水汽浓度。更多还原

【Abstract】 The continuously tunable laser source has been realized in a periodically poled LiNO3 crystal based on difference frequency generation and quasi-phase-matching technique. The pump laser is an 1 W tunable Ti: Sapphire laser with a tunable region from 770 to 870 nm. The signal laser is an 1 W diode-pumped monolithic Nd∶YAG laser. When the grating period is 20 μm and the temperature is tuned between room temperature and 200 ℃, the generated wavelength of idler laser is around 2.8 μm with the general power of 1-2 μW. The direct absorption spectra of (001←000) band of water in laboratory air were measured based on the laser source. The concentration of water vapor in the laboratory air was estimated with an absorption optical path of 8.5 cm in open air更多还原