基于MgO:PPLN的窄线宽2.1μm光学参量振荡器研究

发布时间：2018-11-27 11:24

【摘要】：2.1μm波段激光器在激光医疗、激光雷达、光电对抗等领域都有着广泛的应用,线宽窄化、功率提高是应用需求驱使下2.1μm激光器极为重要的发展方向,具有广阔的发展前景。基于MgO:PPLN准相位匹配技术的光参量振荡器是获得2.1μm激光的有效方法,但该方法受变频简并点、泵浦光线宽和强抽运下的高增益等影响,输出的2.1μm激光线宽较宽,针对这一问题,本论文开展了相关理论和实验研究。理论方面研究了MgO:PPLN晶体调谐特性,基于MgO:PPLN的2.1μm单谐振光参量振荡器增益、阈值及转换效率,优化设计了1.064μm高重频泵浦源及光参量振荡器器件参数。分析了造成2.1μm激光中心波长漂移及线宽展宽的原因,理论计算了2.1μm激光线宽展宽量,并且在此基础上,在保证光谱选择性的前提下,研究了体布拉格光栅器件不同光栅厚度d,光栅的空间频率f和折率调制量δn等参数对线宽窄化的影响。实验方面MgO:PPLN晶体温度固定在50.5°C,采用折叠型外腔泵浦结构,1064nm泵浦功率为12.9W条件下,自由运转时实现了5.51W的简并波长2.1μm激光输出,光谱线宽为109nm,引入VBG光栅器件,获得2.904W窄线宽2.1μm激光输出,线宽被有效压窄至0.17 nm,光-光转换效率达到22.5%。
[Abstract]:2.1 渭 m band lasers have been widely used in the fields of laser medical treatment, lidar, optoelectronic countermeasure and so on. Line width narrowing and power increasing are the most important development directions of 2.1 渭 m laser driven by application demand. It has broad prospects for development. The optical parametric oscillator based on MgO:PPLN quasi-phase matching technique is an effective method to obtain 2.1 渭 m laser. However, this method is affected by the degenerate point of frequency conversion, the width of pumping light and the high gain of strong pump, and the output line width of 2.1 渭 m laser is wider. To solve this problem, this paper carried out theoretical and experimental research. Theoretically, the tuning characteristics of MgO:PPLN crystal are studied. Based on the gain, threshold and conversion efficiency of MgO:PPLN 2.1 渭 m single resonance optical parametric oscillator, the device parameters of 1.064 渭 m high repetition frequency pump source and optical parametric oscillator are optimized. The causes of the center wavelength shift and linewidth broadening of 2.1 渭 m laser are analyzed, and the linewidth broadening amount of 2.1 渭 m laser is calculated theoretically. On the basis of this, the spectral selectivity is guaranteed. The effects of parameters such as space frequency f and fold rate modulation 未 _ n on the width of the grating are studied with different grating thickness of bulk Bragg grating device. The experimental results show that the temperature of MgO:PPLN crystal is fixed at 50.5 掳C, the structure of folded external cavity is adopted, the pump power of 1064nm is 12.9 W, the degenerate wavelength of 5.51 W is 2.1 渭 m, the spectral linewidth is 109 nm, and the output wavelength of 5.51 W is 2.1 渭 m when the pump power of 1064nm is 12.9 W. The VBG grating device is introduced and the 2.904W narrow linewidth 2.1 渭 m laser output is obtained. The linewidth is effectively compressed to 0.17 nm, and the optical-optical conversion efficiency is 22.5%.
【学位授予单位】：长春理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN753.91

【参考文献】