基于双四波混频过程在铯原子气室中产生相干蓝光  

Generation of Coherent Blue Light in Cesium Atom Gas Chamber Based on Dual Four-Wave Mixing Process

作　　者：刘珂鑫 吕昕勃 赵成浩 武寄洲[1,2,3] 马杰 Liu Kexin;LüXinbo;Zhao Chenghao;Wu Jizhou;Ma Jie(State Key Laboratory of Quantum Optics and Quantum Optics Devices,Institute of Laser Spectroscopy,Shanxi University,Taiyuan 030006,Shanxi,China;School of Physics and Electronic Engineering,Shanxi University,Taiyuan 030006,Shanxi,China;Extreme Optics Collaborative Innovation Center,Shanxi University,Taiyuan 030006,Shanxi,China)

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

出　　处：《中国激光》2025年第1期228-233,共6页Chinese Journal of Lasers

基　　金：国家自然科学基金(62020106014,62175140,92165106,12074234);长江学者与创新团队发展计划(IRT17R70);高等学校学科创新引智计划(D18001)。

摘　　要：蓝紫激光在激光制图、数据存储、水下通信、生物学和医学等领域中有着重要应用价值。利用中性碱金属原子,通过四波混频非线性过程,制备紫外、红外以及太赫兹波段等相干光源是一种可行的技术。在铯原子的两个钻石能级系统6S_(1/2)→6P_(3/2)→6D_(3/2)→7P_(3/2)→6S_(1/2)和6S_(1/2)→6P_(3/2)→6D_(3/2)→7P_(1/2)→6S_(1/2)中,当波长为852 nm和921 nm的两束高功率泵浦激光同时作用于6S_(1/2)→6P_(3/2)跃迁和6P_(3/2)→6D_(3/2)跃迁时,在加热的铯原子气室中会发生双四波混频过程。通过频率转换生成了波长为455 nm(7P_(3/2)→6S_(1/2))和459 nm(7P_(1/2)→6S_(1/2))的两束相干蓝光,在无重泵浦光情况下利用852 nm和921 nm泵浦光制备出455 nm和459 nm两束相干蓝光,同时研究了两束泵浦激光的失谐、功率以及铯原子气室温度与产生的两束蓝光强度的关系。Object This study is based on a two-diamond energy level system of cesium atoms described as 6S_(1/2)→6P_(3/2)→6D_(3/2)→7P_(3/2)→6S_(1/2)and 6S_(1/2)→6P_(3/2)→6D_(3/2)→7P_(1/2)→6S_(1/2).When two high-power pump laser beams with wavelengths of 852 nm and 921 nm simultaneously act on the 6S_(1/2)→6P_(3/2)and 6P_(3/2)→6D_(3/2)ultrafine transition lines,a double four-wave mixing process occurs in a heated cesium-atom vapor chamber,and two coherent blue light beams with wavelengths of 455 nm(7P_(3/2)→6S_(1/2))and 459 nm(7P_(1/2)→6S_(1/2))are generated through frequency conversion.The two beams are experimentally studied in the absence of gravity-pump light.The dependence of pump laser detuning,power,and cesium-atom gas chamber temperature on the intensity of the two generated blue light beams is also studied.Methods In this experiment,the 921 nm pump light was generated by a continuously tunable titanium-doped sapphire laser(with a maximum output power of 1 W),while the 852 nm pump light was provided by an external cavity diode laser.After amplification,the maximum output power was 1.2 W.Two sets of half wave plates(HWPs)and polarizing beam splitters(PBS)were used to process these two laser beams.Subsequently,the 921 nm and 852 nm pump lights were reflected by mirror M3 and coincided at the dichroic mirror(DM),propagating in the same direction.After passing through a quarter-wave plate(QWP),both laser beams changed from linearly to circularly polarized light with the same rotation direction,ensuring the highest efficiency in blue light generation.Telescopic systems composed of two lenses with a focal length of 100 mm were placed in front of and behind the cell,with the cell placed at the confocal center to increase the power density acting on the medium.Finally,the angles of the two pump lights were adjusted to satisfy the angle phase-matching condition,and the temperature control system of the Cs atomic vapor chamber was adjusted to satisfy the phase-matching condition.Results and Discussions

关 键 词：四波混频 频率转换 原子能级跃迁 非线性光学 

分 类 号：O437[机械工程—光学工程]