Shaped-pulse optimization of coherent emission of high-harmonic soft X-rays
Shaped-pulse optimization of coherent emission of high-harmonic soft X-rays
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DOI：
10.1038/35018029
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发表时间：
2000-07-13
期刊：
影响因子：
64.8
通讯作者：
Kapteyn, HC
中科院分区：
文献类型：
--
作者：
Bartels, R;Backus, S;Kapteyn, HC
当强激光脉冲聚焦到气体中时，原子电离时发生的光与原子相互作用会导致极其非线性的光学过程(1-3)，即产生驱动激光频率的高次谐波。据报道，谐波高达约 300 阶(4,5)，其中一些对应于超过 500 eV 的光子能量。由于该技术实施简单，并能产生相干、类似激光的软 X 射线束，因此目前正在开发用于科学技术应用；这些包括探索化学和材料系统（6）和成像（7）的动力学。在这里，我们报告说，通过仔细调整强光脉冲的形状（8），我们可以控制电离过程中光与原子的相互作用（9,10），从而将X射线产生的效率提高一个数量级。我们证明可以调整发射辐射的光谱特性，并控制不同阶非线性过程之间的相互作用。
When an intense laser pulse is focused into a gas, the light-atom interaction that occurs as atoms are ionized results in an extremely nonlinear optical process(1-3)-the generation of high harmonics of the driving laser frequency. Harmonics that extend up to orders of about 300 have been reported(4,5), some corresponding to photon energies in excess of 500 eV. Because this technique is simple to implement and generates coherent, laser-like, soft X-ray beams, it is currently being developed for applications in science and technology; these include probing the dynamics in chemical and materials systems(6) and imaging(7). Here we report that by carefully tailoring the shape(8) of intense light pulses, we can control(9,10) the interaction of light with an atom during ionization, improving the efficiency of X-ray generation by an order of magnitude. We demonstrate that it is possible to tune the spectral characteristics of the emitted radiation, and to steer the interaction between different orders of nonlinear processes.