论文标题
增强散装浮雕系统中高谐波产生
Enhancement of High Harmonic Generation in Bulk Floquet Systems
论文作者
论文摘要
我们为定期驱动的系统制定了散装光电流的理论，该理论是外部驱动和激光场频率的混合，因此与未验证的系统相比，谐波谱的扩展。我们以Floquet-Bloch频带及其非绝热的浆果连接和曲率来表达电流。使用此表达式，我们将驱动模型的时空对称性与当前谐波的选择规则相关联。我们通过研究定期驱动的Su-Schrieffer-Heeger模型中的高谐波产生来说明该理论的应用。在高频和低场幅度极限中，我们发现当前谐波的分析表达式。我们还以数值超出高频限制的数值计算电流，并验证当驱动器破坏时间对称时，在非式模型中禁止的谐波可用。此外，即使对于低场幅度，我们发现系统驱动时，我们发现较高谐波的显着增强。我们的工作为固体的非线性光学特性提供了一种统一的浮子方法，这对于通过多个周期性驱动器的电子系统的高谐波光谱进行了实际计算很有用。
We formulate a theory of bulk optical current for a periodically driven system, which accounts for the mixing of external drive and laser field frequencies and, therefore, the broadening of the harmonic spectrum compared to the undriven system. We express the current in terms of Floquet-Bloch bands and their non-adiabatic Berry connection and curvature. Using this expression, we relate spatio-temporal symmetries of the driven model to selection rules for current harmonics. We illustrate the application of this theory by studying high harmonic generation in the periodically driven Su-Schrieffer-Heeger model. In the high frequency and low field amplitude limit, we find analytical expressions for current harmonics. We also calculate the current numerically beyond the high frequency limit and verify that when the drive breaks a temporal symmetry, harmonics forbidden in the undriven model become available. Moreover, we find significant enhancement in higher harmonics when the system is driven, even for low field amplitudes. Our work offers a unified Floquet approach to nonlinear optical properties of solids, which is useful for realistic calculations of high harmonic spectra of electronic systems subject to multiple periodic drives.
