论文标题
从双层纳米建筑
Electron-Backscattering-Assisted High Harmonic Generation from Bilayer Nanostructures
论文作者
论文摘要
在时间依赖性密度功能理论的框架中，我们从具有层间间距D =70Å的双层晶体的光子晶体中获得了高达10个光子能量的高阶谐波。在放牧发生率时，在谐波谱中观察到明显的双倍结构。第二高原的光子能量远远超出了原子样谐波，可以通过包括电离电子的反向散射来很好地解释。从头算模拟表明，第二高原的截止值随着d的增加而不断扩展。我们的经典计算预测，最大电子动能在较大范围内线性取决于d。此外，第二个高原中的谐波产量通过驱动激光波长的增加而显着提高。由于电子波数据包的限制扩散，因此获得了有益的波长尺度。因此，这项研究建立了一种基于分层纳米结构的高能光源的新颖而有效的方式。
In the framework of time-dependent density functional theory, we obtain high-order harmonics of photon energies up to 10 Up from bilayer crystals with an interlayer spacing d = 70 Å. At grazing incidence, a clear double-plateau structure is observed in the harmonic spectrum. The photon energy of the second plateau far beyond atomic-like harmonics can be well explained by the inclusion of backscattering of ionized electrons. Ab initio simulations reveal that the cutoff of the second plateau is continuously extended with an increasing d. Our classical calculations predict that the maximum electronic kinetic energy is linearly dependent on d over a wide range. Moreover, the harmonic yield in the second plateau is significantly enhanced by increases in the wavelength of the driving laser. Owing to the confined spreading of the electronic wave packet, a beneficial wavelength scaling of λ2.85 is obtained. This study therefore establishes a novel and efficient way of producing high-energy light source based on layered nanostructures.
