[1] Werle P, Slemr F, Maurer K et al.. Near- and mid-infrared laser-optical sensors for gas analysis [J]. Opt. Lasers Engng. 2002, 37:101～114

[2] Cornelia F, Markus W. Sigrist. Mid-IR difference frequency generation[J]. Topics. Appl. Phys. 2003, 89: 97～143

[3] Chen W, Mouret G, Boucher D et al.. Mid-infrared trace gas detection using continuous-wave difference frequency generation in periodically poled RbTiOAsO4[J]. Appl. Phys. B, 2001,72:873～876

[4] Richter D, Fried A, Wert B P et al.. Development of a tunable mid-IR difference frequency laser source for highly sensitive airborne trace gas detection[J].Appl. Phys. B, 2002, 75: 281～288

[5] Li Xiaoqin, Jiang Jian, Wang Zhishan et al.. Widely tunable continuous wave mid-IR difference-frequency generation source with fiber laser and amplifier[J] . Acta Optica Sinica,2007, 27(10):1807～1811

[6] Fried A, Henry B, Wert B et al.. Laboratory, ground-based, and airborne tunable diode laser systems: performance characteristics and applications in atmospheric studies[J]. Appl. Phys. B, 1998, 67:317～330

[7] Gmachl C, Straub A, Colombelli R et al.. Single-mode, tunable distributed-feedback and multiple wavelength quantum cascade lasers[J]. IEEE Quant. Electron., 2002, 38(6):569～581

[8] Armin L. Quantum cascade lasers, systems, and applications in Europe[C]. SPIE,2005, 5732: 122～133

[9] Yao Jianquan. Development of nonlinear optical frequency conversion and quasi-phase matching technology[J]. Journal of Synthetic Crystals, 2002, 31(3): 201～207

[10] Liang Xiaoyan, Hou Wei, Lü Junhua et al.. All-solid-state pumped tunable PPLN optical parametric oscillator[J]. Acta Optica Sinica, 2001, 21(9): 1148～1149

[11] Wang Tao, Yao Jianquan, Yu Daoyin et al.. Research on the generation of FWM going with PPLN- OPO[J]. Chin. J. Laser,2004, 31(3):284～288

[12] Deng Ying, Zhu Qihua, Zeng Xiaoming et al.. Angle optimization for ultra-short mid-infrared non-collinear phase matching optical parametric amplifyication in MgO：LiNbO3 crystal[J]. Chin. J. Laser, 2007, 34(7): 915～919

[13] Yao Jianghong, Xue Liangping, Yan Boxia et al.. Optical parametric oscillator based on periodically poled MgO：LiNbO3 crystal[J]. Chin. J. Laser, 2007, 34(2):209～213

[14] Zhang Xingbao, Yao Baoquan, Wang Yuezhu et al.. Middle-infrared intracavity periodically MgO:LiNbO3 optical parametric oscillator. Chin. Opt. Lett., 2007, 5(7):426～427

[15] Jundt D.Temperature-dependent sellmeier equation for the index of refraction, ne, in congruent lithium niobate[J]. Opt. Lett., 1997, 22(20):1553～1555

[16] Tittel F K, Richter D, Fried A. Mid-Infrared laser applications in spectroscopy[J]. Topics. Appl. Phys., 2003,89:445～516