Creating alignment echoes using a phase-shaped femtosecond laser pulse
Creating alignment echoes using a phase-shaped femtosecond laser pulse
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DOI：
10.1088/1361-6455/ac701c
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发表时间：
2022-05
期刊：
影响因子：
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通讯作者：
Shuwu Xu;Guizhen Liu;Yunxia Huang
中科院分区：
文献类型：
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作者：
Shuwu Xu;Guizhen Liu;Yunxia Huang
近年来，由一对延时飞秒激光脉冲引起的分子定向回波被提出并引起了广泛的研究兴趣。然而，我们证明了用v型光谱相位调制的形飞秒激光脉冲可以替代地产生对准回波。通过定制的两个延时子脉冲的激发，形成了完整的、分数的和虚的对准回波。通过设计调制参数来诱导不同类型的回波，可以很容易地控制延迟时间和两个子脉冲之间的强度比。结果表明，产生最大全回波对准度的两个子脉冲的最佳强度比与子脉冲的能量密切相关。当脉冲能量较低时，当两个子脉冲强度相等时，获得最大的全回波对准度。最佳强度比随第一泵浦脉冲激发能量的增大而增大。
In recent years, molecular alignment echoes induced by a pair of time-delayed femtosecond laser pulses have been proposed and have aroused wide research interest. However, we demonstrate that an alignment echo can be alternatively produced by a shaped femtosecond laser pulse with a V-style spectral phase modulation. The full, fractional, and imaginary alignment echoes are formed by the excitation of the tailored two time-delayed sub-pulses. Both the delay time and the ratio of intensity between the two sub-pulses can be easily manipulated by designing the modulation parameters to induce various types of echoes. We further show that the optimal ratio of intensity between the two sub-pulses, which results in the maximal alignment degrees of the full echo, closely correlates with the energy of the sub-pulse. When the pulse energy is relatively low, the maximal alignment degree of the full echo is obtained when the two sub-pulses have equal intensity. The optimal ratio of intensity increases with the excitation energy of the first pump pulse.