Formation and amplification of subfemtosecond x-ray pulses in a plasma medium of hydrogenlike ions with a modulated resonant transition
Formation and amplification of subfemtosecond x-ray pulses in a plasma medium of hydrogenlike ions with a modulated resonant transition
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具有调制共振跃迁的类氢离子等离子体介质中亚飞秒 X 射线脉冲的形成和放大
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发表时间：
2017
期刊：
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通讯作者：
O. Kocharovskaya
中科院分区：
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作者：
T. Akhmedzhanov;V. Antonov;A. Morozov;A. Goltsov;M. Scully;S. Suckewer;O. Kocharovskaya
相干强阿秒x射线脉冲可以导致生物大分子和其他材料纳米结构的快速动态成像，具有创纪录的高时间和空间分辨率的独特组合。基于等离子体的x射线激光源能够产生高能x射线脉冲，但具有相对较长的皮秒持续时间。基于激光场高谐波产生（HHG）的光源可以产生更短的脉冲，但能量更低。我们提出了两种通往强亚飞秒x射线源的不同途径，即i)通过在共振吸收介质中将x射线等离子体激光器的皮秒辐射有效转化为亚飞秒脉冲序列，ii)通过在x射线等离子体激光器的活性介质中放大HHG辐射。我们展示了本质上相同的技术可以用于实现这两条路径。这种技术是在足够强的红外或光场作用下产生的共振跃迁（相应地在吸收或放大介质中）参数的调制。我们提出在i)中红外激光场调制的Li III离子和ii)光学激光辐射调制的cvi离子的被动/主动介质中实验实现所建议的技术。
Coherent intense attosecond X-ray pulses could lead to a fast dynamical imaging of the biological macro-molecules and other material nanostructures with a unique combination of a record high temporal and spatial resolution. Plasma based X-rays laser sources are capable to produce high energy X-ray pulses but with relatively long picosecond duration. The sources based on high-harmonic generation (HHG) of a laser field allow to produce much shorter pulses but of lower energy. We suggest two different paths towards intense sub-femtosecond X-ray sources, namely i) via efficient transformation of the picosecond radiation of the X-ray plasma lasers into the trains of sub-femtosecond pulses in a resonantly absorbing medium, and ii) via amplification of HHG radiation in the active medium of the X-ray plasma lasers. We show that essentially the same technique can be used for realization of both paths. This technique is a modulation of the parameters of the resonant transition (accordingly in absorbing or amplifying medium) produced under the action of sufficiently strong infrared or optical field. We propose experimental realization of the suggested technique in the passive/active media of i) Li III ions modulated by the mid-IR laser field and ii) C VI ions modulated by the optical laser radiation.