碘分子吸收稳定中红外差频激光频率  

Frequency Stabilization of Mid-Infrared Difference Frequency Laser by Iodine Molecule Absorption

作　　者：孙明国[1,2] 马宏亮[1] 王贵师 汪磊[2] 曹振松[1] 梁万国[3] 陈怀曦 周煌[3] 邹小林[3] 陈卫东 高晓明[1,2] 

机构地区：[1]中国科学院安徽光学精密机械研究所中国科学院大气成分与光学重点实验室,安徽合肥230031 [2]中国科学院安徽光学精密机械研究所大气物理化学研究室,安徽合肥230031 [3]中国科学院福建物质结构研究所,福建福州350002 [4]法国滨海大学大气物理化学实验室,法国敦刻尔克59140

出　　处：《中国激光》2014年第7期42-47,共6页Chinese Journal of Lasers

基　　金：国家自然科学基金(41205021;41175036);中国科学院大气成分与光学重点实验室开放基金

摘　　要：差频光源用于大气分子稳定同位素丰度研究需要频率稳定的连续输出的空闲光。基于连续可调谐钛宝石激光器和单频连续Nd:YAG激光器建立差频系统,为了稳定差频系统产生的红外光源的波长,利用MgO:PPLN作为倍频晶体,采用有多普勒展宽的碘分子吸收稳频方法,结合数字比例-积分-微分(PID)反馈控制技术,将Nd:YAG激光器的频率漂移量稳定在1.2MHz/h内,稳定度为4.26×10-9。实验结果表明:增加对压电陶瓷(PZT)的调制电压时,Nd:YAG激光在1h内的频率漂移量迅速减小,超过1V后漂移量趋于稳定;改变对PZT调制频率没有获得较高的稳定度。将频率稳定后的Nd:YAG激光用于产生3.42μm附近的差频光源,通过对低压下CH4气体分子吸收谱线的测量,去卷积运算得到差频系统的线宽约为6.9MHz。实验结果既为该方法用于稳定激光频率提供了重要的参考,又为痕量气体探测提供了频率稳定的差频光源。Difference frequency laser used for the study of atmospheric molecule isotope abundance requires stable frequency and continuous idler radiation.A difference frequency generation（DFG）system is established based on a tunable continuous wave（CW）Ti：sapphire laser and a CW single-frequency Nd：YAG laser.In the DFG system,frequency stabilization method of iodine molecule Doppler-broadened absorption combined with digital proportion integration differentiation（PID）feedback control technology is adopted to stabilize the wavelength of infrared laser arised from the DFG system,while MgO：PPLN is used as the frequency doubling crystal.The Nd：YAG laser frequency shift is stabilized within 1.2 MHz/h and the stability is 4.26×10^-9.The experimental results show that the frequency shift within 1 h of Nd：YAG laser decreases rapidly with the increase of the voltage loaded on piezoelectric ceramic（PZT）,but smaller shift is not achieved beyond 1 V;better stability is not achieved by changing the frequency of modulation voltage.Nd：YAG laser with stabilized frequency is used to generate difference frequency laser near 3.42μm.By detecting low pressure absorption line of CH4,the 6.9 MHz line width of this difference frequency system is derived.The results provide not only an important reference for laser frequency stabilization by this technology,but also a stable difference frequency laser for trace gas detection.

关 键 词：非线性光学 激光稳频 数字比例-积分-微分技术 一次谐波 差频产生 

分 类 号：TN248.1[电子电信—物理电子学]