论文标题
通过破坏性干扰形成固态高阶谐波产生高原
Formation of the solid-state high-order harmonic generation plateau through destructive interference
论文作者
论文摘要
在经常研究的固态高谐波生成的两种波段模型中，原则上的频带谐波可以从最小值到最大带隙范围。但是，众所周知，除非激光强度如此之高，以至于电子探索整个Brillouin区域，否则存在激光强度依赖性临界值。我们表明，这种激光依赖性截止是由从布里渊区的不同初始状态开始的电子发射的破坏性干扰而形成的。这项工作中的计算是针对Su-Schrieffer-Heeger链条的，但我们的发现也适用于其他两波段系统。只有当布里渊区的采样足够细，或者等效地，有限链在位置空间中足够长，破坏性干扰才完成并形成截止。对于更粗的采样和较短的链条，发出了最小和最大带隙之间的所有谐波。时频分析表明了某些轨迹如何负责截止的形成。
In frequently studied two-band models for solid-state high-harmonic generation, interband harmonics in principle can range from the minimum to the maximum bandgap. However, it is known that a laser-intensity dependent cutoff exists that may be well below the maximum bandgap unless the laser intensity is so high that the electrons explore the entire Brillouin zone. We show that this laser-intensity dependent cutoff is formed by destructive interference of the emission of electrons starting at different initial states in the Brillouin zone. The calculations in this work are for Su-Schrieffer-Heeger chains but our findings apply to other two-band systems as well. Only when the sampling of the Brillouin zone is fine enough or, equivalently, a finite chain is long enough in position space, the destructive interference is complete and forms the cutoff. For coarser sampling and shorter chains all harmonics between minimum and maximum bandgap are emitted. A time-frequency analysis shows how certain trajectories are responsible for the formation of the cutoff.
