| 3～5μm mid-infrared laser has applications in military confrontation, biomedical, and gas detection. In this thesis1064nm pulse all-solid-state laser is used as a pumping source and MgO:PPLN is uesd as parametric media. The mid-infrared laser is produced by the use of quasi-phase-matching techniques and optical parametric generation.The thesis from the three-wave interaction equation, analyze the basic principles and characteristics of the of quasi-phase matching, By the relationship of three light field photons changes and expression of optical gain in the process by OPG, obtain the gain conditions to affect the parameters of the optical. According ABCD transmission matrix of Gaussian beam to design stable pumped source of OPG system, then analog tuning curve of periodically poled crystal.In the experiment we combine the period tuning of crystal cycle with the temperature tuning (the temperature range is30℃～120℃), the tuning range of the signal light is1477～1790nm, idler light tuning range is2627nm～3815nm. The3.8μm mid-infrared laser is achieved when the period of crystal is29.52μm and the temperature is30℃. The power of3.8μm laser is495mW when the1064nm power is6.23W, pulse width is27.5ns, and frequency is20kHz. |
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