基于铯原子气室反抽运光增强相干蓝光  

Coherent blue light enhancement via repumping laser in cesium vapor

作　　者：黄文艺 杨保东[1,2,3] 樊健 王军民 周海涛 Huang Wen-Yi;Yang Bao-Dong;Fan Jian;Wang Jun-Min;Zhou Hai-Tao(College of Physics and Electronic Engineering,Shanxi University,Taiyuan 030006,China;State Key Laboratory of Quantum Optics and Quantum Optics Devices and Institute of Opto-Electronics,Shanxi University,Taiyuan 030006,China;Collaborative Innovation Center of Extreme Optics,Shanxi University,Taiyuan 030006,China)

机构地区：[1]山西大学物理电子工程学院,太原030006 [2]山西大学光电研究所,量子光学与光量子器件国家重点实验室,太原030006 [3]山西大学极端光学协同创新中心,太原030006

出　　处：《物理学报》2022年第18期330-336,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61975102,11974226);山西省自然科学基金(批准号:20210302123437);国家重点研发计划(批准号:2017YFA0304502);山西省高等学校科技创新项目(批准号:2019L0101)资助的课题。

摘　　要：基于铯原子菱形能级6S_(1/2)(F=4)→6P_(5/2)(F’=5)→6D(F’’=6)→7P_(3/2)(F’=5)→6S_(1/2)(F=4)系统,在波长为852 nm(6S_(1/2)→6P_(3/2))和917 nm(6P_(5/2)→6D)两红外抽运激光共同激励下,通过四波混频过程频率上转换产生了波长为455 nm(7P_(3/2)→6S_(1/2))的相干、准直蓝光.实验上详细研究了抽运光偏振组合、功率、铯原子气室温度对蓝光强度的影响.在此基础上,通过增加了一束波长为894 nm(6S_(1/2)(F=3)→6P_(5/2)(F’=3,4))的反抽运激光,将更多的原子抽运回基态6S_(1/2)(F=4)超精细能级,显著增加了相干蓝光功率的输出,在水下自由空间光通信领域等有一定的应用价值.We demonstrate the generation of coherent and collimated blue light(CBL)based on cesium(Cs)6S_(1/2)(F=4)→6P_(5/2)(F’=5)→6D(F’’=6)→7P_(3/2)(F’=5)→6S_(1/2)(F=4)diamond-type atomic system in a heated vapor cell.Two infrared pumping lasers with wavelengths at 852 nm(6S_(1/2)→6P_(3/2))and 917 nm(6P_(5/2)→6D),provide step-wise excitation to the 6Dexcited state,and induce strong two-photon coherence between the 6S_(1/2)state and 6Dstate.The atoms undergo a double cascade accompanied with the amplified spontaneous emission at 15.1μm via the 7P_(3/2)intermediate excited state,and produce a beam of 455 nm(7P_(3/2)→6S_(1/2))CBL with highly spatiotemporal coherence through a parametric four-wave mixing process.We investigate the influence of experimental parameters such as polarization combination of the two pumping lasers,and their power,and the temperature of Cs vapor cell on the CBL.Especially,we add a beam of 894 nm laser operating at the 6S_(1/2)(F=3)→6P_(5/2)transition as repumping laser,which can pump atoms back to the 6S_(1/2)(F=4)state from the 6S_(1/2)(F=3)state,thus significantly improving the power of CBL.This technique of the CBL enhancement via optical pumping is also useful for the other alkali metal atoms.

关 键 词：四波混频 非线性光学 频率转换 反抽运光 

分 类 号：O562.3[理学—原子与分子物理]