周期极化铌酸锂晶体的红外光谱测量分析

对周期极化非线性品体的光参量振荡器实现连续调谐输出的条件进行了理论模拟和分析,并且针对基于多周期的掺镁铌酸锂晶体光参量振荡器进行了实验研究,在掺镁铌酸锂晶体内制作了6个等间隔的晶畴区,其间距为0.5 μm,极化周期范围为29.0～31.5 μm.在室温下采用LD端面抽运的声光调Q Nd:YVO4激光器作泵浦源,实现了PPMgLN光参量振荡器的信号光在1449.7～1665.0 nm、闲频光在3 989.2～2 946.0 nm范围内的调谐输出,其最低激射阈值为108.0 mW、最高激射阈值为149.2 mW.当泵浦功率为649 mW时,获得了信号光最高为118.5 mW的输出,其光-光转换效率为18.26%;闲频光最高输出为46.6 mW,其光一光转换效率为7.18%.以上参数均接近实用化水平.而且,这两个波段的光源分别在整个光纤通信的S+C+L波段和大气层透射窗口范围,具有十分重要的应用前景.

Measuring and Analyzing Infrared Spectrum of Periodically Polarized Lithium Niobate

The present paper reports theoretical and experimental research on the tunable output characteristics of periodically polarized lithium niobate. We made six equal distance crystal grating sections, with each distance being 0.5 mm and the polarization period range of 29.0-31.5 mm. Especially, at room temperature, the signal-wavelength tunable output in the range of 1 449.7-1 665.0 nm and idle-wavelength tunable output in the range of 3 989.2-2 946.0 nm were achieved by LD end-pumped Nd∶YVO4 laser with Q-switch in sound-wave. The lowest excitation threshold was 108.0 mW, while the highest excitation threshold was 149.2 mW. When the pump power was 649 mW, the highest gained signal-wave output was 118.5 mW and its conversion efficiency was 18.26%. Meanwhile, the idle-wave output was 46.6 mW and its conversion efficiency was 7.18%. These parameters approached the practicality level.