基于多周期MgO∶PPLN的内腔宽调谐连续中红外光参量振荡器

Wide Tunable Contunuous-wave Mid Infrared Intro-cavity Optical Parametric Oscillator Based on Multi-period MgO∶PPLN

报道了一种内腔光参量振荡器,该器件通过改变多通道MgO∶PPLN极化晶体的极化周期和温度,可以快速实现3.2~4.1μm中红外参量光可调谐连续输出.采用1.064μm谐振腔与多光参量振荡腔折叠型复合结构,考虑晶体热效应及宽范围调谐参量光振荡过程中光斑模式匹配,通过对两个子腔谐振结构的数值模拟分析,确定最佳腔型结构参数.基于该谐振腔结构,实验研究了多周期MgO∶PPLN晶体的温度和极化周期对参量光波长的影响,实验中克服了MgO∶PPLN晶体在3.8~4.1μm中红外波段较为严重的本征吸收以及量子亏损导致的效率降低问题,获得2.78~4.18μm中红外激光连续调谐输出,调谐范围达1.399μm.在3.2μm、3.5μm、3.8μm、4.1μm四个典型波长下实现了参量光输出,功率分别为1.72W、1.39W、0.79W和0.442W,对应转化效率分别为7.17%、5.4%、3.1和1.84%.

A tunable continuous-wave（ CW） internal cavity pump optical parametric oscillator（ OPO） based on multi poled period Mg O∶ PPLN was reported. The 3. 2 - 4. 1 μm wide tuning mid-infrared parametric light was obtained in real time by changing the poled periods and temperature. The thermal effect and spot modes matching during OPO＇ s wide tuning process were considered. It used a folded type doubly cavities which consisted of 1. 064 μm resonator and optical parametric oscillator. The optimum parameters of the cavity structure was determined on account of the numerical simulation and theoretical analysis results. The theoretical simulation of tuning characteristics of OPO was carried out. Based on this structure,the effect of temperature and polarization period on output wavelength was experimentally investigated. It overcame the sever absorption and the quantum loss of Mg O∶ PPLN in the 3. 8 - 4. 1 μm mid-infrared band. Continuous wide range tunable output of 2. 78 - 4. 18 μm in mid-infrared radiation was achieved. The tuning range was up to 1. 399 μm. The output power of 3. 2 μm,3. 5 μm,3. 8 μm and 4. 1 μm parametric light was 1. 72 W,1. 39 W,0. 79 W and0. 442 W,the corresponding conversion efficiency was 7. 17%,5. 4%,3. 1%,1. 84% and 1. 72 W.