Sundström Andréas, Grech Mickael, Pusztai István, Riconda Caterina
Department of Physics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
LULI, CNRS, Sorbonne Université, CEA, École Polytechnique, Institut Polytechnique de Paris, F-91128 Palaiseau, France.
Phys Rev E. 2022 Oct;106(4-2):045208. doi: 10.1103/PhysRevE.106.045208.
We present a scheme for amplifying an extreme-ultraviolet (XUV) seed isolated attosecond pulse via stimulated Raman scattering of a pulse-train pump. At sufficient seed and pump intensity, the amplification is nonlinear, and the amplitude of the seed pulse can reach that of the pump, one order of magnitude higher than the initial seed amplitude. In the linear amplification regime, we find that the spectral signature of the pump pulse train is imprinted on the spectrum of the amplified seed pulse. Since the spectral signature is imprinted with its frequency downshifted by the plasma frequency, it is possible to deduce the electron density in the region of interaction. This region can be of micrometer length scale longitudinally. By varying the delay between the seed and the pump, this scheme provides a local electron-density measurement inside solid-density plasmas that cannot be probed with optical frequencies, with micrometer resolution.
我们提出了一种通过脉冲序列泵浦的受激拉曼散射来放大孤立阿秒极紫外（XUV）种子脉冲的方案。在足够的种子脉冲和泵浦强度下，放大是非线性的，种子脉冲的振幅可以达到泵浦脉冲的振幅，比初始种子脉冲振幅高一个数量级。在线性放大区域，我们发现泵浦脉冲序列的光谱特征会印刻在放大后的种子脉冲光谱上。由于光谱特征以其频率相对于等离子体频率向下偏移的形式被印刻，所以可以推断出相互作用区域的电子密度。该区域在纵向可能具有微米级的长度尺度。通过改变种子脉冲和泵浦脉冲之间的延迟，该方案能够在无法用光学频率探测的固体密度等离子体内部进行具有微米分辨率的局部电子密度测量。
