Extracting electron dynamics in solids via observation of low-order harmonics of tailored strong fields.

阿秒科学的最新进展预示着固体物理学的范式转变。以长脉冲和频域分析为基础的旧框架目前正被以时间为基础的图像和强超短脉冲为基础的新框架所取代。在这个项目中，我们的目标是寻找内部的光学周期重建阿秒带间和带内的动态使用时间和偏振定制的双色场，以及定制的样品几何形状的基础上的光子晶体和纳米结构，以促进相位匹配和对称性破缺的固体。我们使用的腔内增强近红外驱动场可从第一QUTIF期间。在这些定制的领域，最低的辐射谐波有效地产生。谐波仔细分析的计划，以及在以前的QUTIF期间，所谓的全光学attocock，允许重建的细节，如电离延迟阿秒时间尺度上的电子动力学。理论预测，全光时钟能够解开低阶谐波产生背后的不同机制，即磁化率贡献（束缚-束缚），Brunel辐射（束缚-自由），最后是再碰撞谐波（束缚-自由-束缚）。该项目的目的是首次在实验上演示全光时钟，并在实验和理论之间密切相互作用的亚周期尺度上研究半导体和微电子中的非线性电子动力学。这不仅可以更好地理解固体的非线性光学性质，而且可以获得有效的谐波源，例如在THz光谱范围内。

Recent advances in attosecond science herald a paradigm change in solid-state physics. The old framework, based on long pulses and a frequency domain analysis is being currently replaced by the new one, relying on a time-based picture and strong ultrashort pulses. In this project we aim to look inside the optical cycle to reconstruct the attosecond inter- and intraband dynamics in solids using temporally and polarizationally tailored two-color fields as well as tailored sample geometries based on photonic crystals and nanostructures to facilitate phase-matching and symmetry breaking. We use the intracavity enhanced near-infrared driving fields available from the first QUTIF period. In these tailored fields, lowest radiation harmonics are efficiently generated. The harmonics are carefully analyzed with a scheme developed in the previous QUTIF period as well, the so-called all-optical attoclock, allowing to reconstruct the details of electron dynamics such as ionization delay on attosecond time scales. Theory predicts that the all-optical attoclock is capable of disentangling the different mechanisms behind the generation of low-order harmonics, namely the susceptibility contribution (bound-bound), the Brunel radiation (bound-free), and finally the re-collision harmonics (bound-free-bound). Aim of this project is the first experimental demonstration of the all-optical attoclock and the investigation of the nonlinear electron dynamics in semiconductors and dielectrics on the sub-cycle scale in close interplay between experiment and theory. This leads not only to a better understanding of the nonlinear optical properties of solids, but also to efficient harmonic sources e.g. in the THz spectral range.