Dynamic Rabi sidebands in laser-generated microplasmas: Tunability and control
Dynamic Rabi sidebands in laser-generated microplasmas: Tunability and control
复制标题
激光产生的微等离子体中的动态拉比边带：可调性和控制
DOI：
10.1103/physreva.83.053423
复制
发表时间：
2011
期刊：
影响因子：
--
通讯作者：
R. Levis
中科院分区：
文献类型：
--
作者：
R. Compton;A. Filin;D. Romanov;R. Levis
在泵浦探测实验中，利用大气中的微等离子体通道产生了光频范围内的宽带相干辐射。通过聚焦的强飞秒泵浦脉冲在气体中产生微等离子体介质。然后，皮秒探测脉冲与微等离子体通道相互作用，产生与发光线相关的宽的相干边带，并且相对于激光载波频率发生红移和蓝移。这些边带起源于由探测脉冲耦合的激发态对之间的诱导拉比振荡。因此，边带辐射强度跟踪微等离子体演化。边带产生广泛的和可调的拉比位移对应于探测脉冲中的电场幅度的变化值。{approximate}10{sup 10} W cm{sup -2}的探测光束产生的载波频率的最大边带偏移>90 meV，从而产生200 meV的有效带宽。边带可以通过探测脉冲的强度和时间轮廓来调谐和控制。在微等离子体中观察到的相干性的事实表明，拉比循环是可能的，在高温下具有适度高的激光强度，只要转换接近驱动频率（{Delta}{approx}2%{omega}{sub c}）是可用的。等离子体激发更多»与拉比位移测量相结合，还可以同时提取多组高激发态之间的跃迁偶极矩的定量比率，并在光学范围内进行跃迁。«少
Broadband, coherent radiation in the optical-frequency range is generated using microplasma channels in atmospheric gases in a pump-probe experiment. A microplasma medium is created in a gas by a focused intense femtosecond pump pulse. A picosecond probe pulse then interacts with this microplasma channel, producing broad, coherent sidebands that are associated with luminescence lines and are redshifted and blueshifted with respect to the laser carrier frequency. These sidebands originate from the induced Rabi oscillations between pairs of excited states that are coupled by the probe pulse. Thus the sideband radiation intensity tracks the microplasma evolution. The sidebands arise from broad and tunable Rabi shifts corresponding to varying values of the electric-field magnitude in the probe pulse. The {approx}10{sup 10} W cm{sup -2} probe beam creates a maximum sideband shift of >90 meV from the carrier frequency, resulting in an effective bandwidth of 200 meV. The sidebands can be tuned and controlled by the intensity and temporal profile of the probe pulse. The fact that the coherence is observed in a microplasma demonstrates that Rabi cycling is possible at high temperature with moderately high laser intensities as long as transitions close to the driving frequency ({Delta}{approx}2%{omega}{sub c}) are available. Plasma excitation more » combined with Rabi-shifting measurements also serves as a means to simultaneously extract quantitative ratios for the transition-dipole moments between multiple sets of highly excited states with transitions in the optical regime. « less