不同原子在飞秒强激光场中的里德堡态激发和双电离  

Rydberg state excitations and double ionizations of different atoms in strong femtosecond laser field

作　　者：赵磊[1] 张琦[1] 董敬伟[1] 吕航[1] 徐海峰[1] 

机构地区：[1]吉林大学原子与分子物理研究所,长春130012

出　　处：《物理学报》2016年第22期23-29,共7页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2013CB922200);国家自然科学基金(批准号:11534004;U1532138;11274140)资助的课题~~

摘　　要：利用质量分辨的脉冲电场电离方法结合飞行时间质谱,系统地研究了He,Ar和Xe原子在800 nm飞秒强激光场中的里德堡态激发过程,并将其与非序列双电离过程进行了比较,探讨了激发与非序列双电离过程的区别,以及不同原子里德堡态激发过程的规律性变化.研究结果有助于深入了解强激光场中原子里德堡态激发的物理机理.We experimentally investigate the Rydberg state excitations（RSEs） of noble gas atoms,He,Ar and Xe,in an800-nm 50-fs strong laser field,by using the mass resolved pulsed electric field ionization method combined with the time-of-flight mass spectrometer.We measure the yields of the atomic RSE at different laser intensities and ellipticities,and compare the results with those of the nonsequential double ionization（NSDI） in strong laser fields.Our study shows that like that of NSDI,the yield of the atomic RSE increases as the atomic number increases,i.e.,RSE yield trend is HeArXe.On the other hand,for any of the atoms,the probability of NSDI is lower than that of total RSE at the same laser intensity,which can be understood as that the yield of high energy electrons（for NSDI） is less than that of low energy electrons that can be captured into the Rydberg states.Additionally,our results show that the RSE yield strongly depends on the laser ellipticity,which is completely suppressed by a circularly polarized laser field.The dependence of RSE on laser ellipticity turns weaker as the atomic number increases,and is weaker than that of NSDI for any of the atoms.It is indicated that the atomic RSE in strong laser field can be attibuted to the capture of the low energy electrons after tunneling ionization into Rydberg states by the Coulomb potential at the end of the laser pulse.

关 键 词：里德堡态激发 隧穿电离 强激光场 双电离 

分 类 号：O562.4[理学—原子与分子物理]