基于双光子不对称色锁二阶随机关联的阿秒极化拍研究  

Two-photon asymmetric color-locking second-order stochastic correlation of attosecond polarization beats

作　　者：甘琛利 张彦鹏[2] 余孝军[2] 聂志强[2] 李岭[2] 宋建平[2] 葛浩[2] 姜彤[2] 张相臣[2] 卢克清[3] 

机构地区：[1]Department of Physics,University of Arkansas,Fayetteville,Arkansas 72701,USA [2]西安交通大学电子物理与器件教育部重点实验室 [3]中国科学院西安光学精密机械研究所瞬态光学技术国家重点实验室

出　　处：《物理学报》2007年第5期2670-2677,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:60308002;60678005);全国博士学位论文作者专项基金(批准号:200339);教育部科学技术研究重点项目(批准号:105156);霍英东教育基金会高等院校青年教师基金(批准号:101061);高等学校博士学科点专项科研基金(批准号:20050698017)资助的课题~

摘　　要：基于两双光子过程的相位共轭二阶极化干涉,从理论上研究了四能级系统在阿秒量级的不对称和频极化拍频(FASPB).在抽运光束为窄带情形下,场关联对FASPB信号影响很弱.在宽带情形下,FASPB信号表现出共振-非共振交叉关联,双光子信号展现出混合辐射-物质失谐的THz阻尼振荡,即当激光频率偏离双光子共振跃迁的条件时,信号将呈现阻尼振荡,而且其双光子自相关信号的包络还呈现最大值零延时不对称.还研究了由于两双光子自相关过程零延时的偏差导致的阿秒拍频信号的不对称性,和两个双光子信号的最大值分别向相反的方向偏离零延时点的现象.FASPB作为一种阿秒超快调制过程,从理论上说它可以扩展到任何两偶极禁戒跃迁激发态的能级和系统.Based on the phase-conjugation polarization interference between two two-photon processes, we theoretically investigated the attosecond scale asymmetry sum-frequency polarization beat in four-level system （FASPB）. The field correlation has weak influence on the FASPB signal when the laser has narrow bandwidth. Conversely, when the laser has broadband linewidth, the FASPB signal shows resonance-nonresonance cross correlation. The two-photon signal exhibits hybrid radiation-matter detuning temhertz damping oscillation, i. e., when the laser frequency is off resonance from the two-photon transition, the signal exhibits damping oscillation and the profile of the two-photon self-correlation signal also exhibits zero time-delay asymmetry of the maxima. We have also investigated the asymmetry of attosecond polarization beat caused by the shift of the two-photon self- correlation zero time-delay phenomenon, in which the maxima of the two two-photon signals are shifted from zero time-delay point to opposite directions. As an attosecond uhrafast modulation process, FASPB can be intrinsically extended to any level-summation systems of two dipolar forbidden excited states.

关 键 词：阿秒和频 极化拍 四能级 双光子 

分 类 号：O437.1[机械工程—光学工程]