Heinrich Tobias, Taucer Marco, Kfir Ofer, Corkum P B, Staudte André, Ropers Claus, Sivis Murat
4th Physical Institute-Solids and Nanostructures, University of Göttingen, Göttingen, Germany.
Joint Attosecond Science Laboratory, National Research Council of Canada and University of Ottawa, OttawaON, Canada.
Nat Commun. 2021 Jun 17;12(1):3723. doi: 10.1038/s41467-021-23999-9.
Strong-field methods in solids enable new strategies for ultrafast nonlinear spectroscopy and provide all-optical insights into the electronic properties of condensed matter in reciprocal and real space. Additionally, solid-state media offers unprecedented possibilities to control high-harmonic generation using modified targets or tailored excitation fields. Here we merge these important points and demonstrate circularly-polarized high-harmonic generation with polarization-matched excitation fields for spectroscopy of chiral electronic properties at surfaces. The sensitivity of our approach is demonstrated for structural helicity and termination-mediated ferromagnetic order at the surface of silicon-dioxide and magnesium oxide, respectively. Circularly polarized radiation emanating from a solid sample now allows to add basic symmetry properties as chirality to the arsenal of strong-field spectroscopy in solids. Together with its inherent temporal (femtosecond) resolution and non-resonant broadband spectrum, the polarization control of high harmonics from condensed matter can illuminate ultrafast and strong field dynamics of surfaces, buried layers or thin films.
固体中的强场方法为超快非线性光谱学提供了新策略，并能在倒易空间和实空间中对凝聚态物质的电子特性进行全光洞察。此外，固态介质为利用改性靶材或定制激发场来控制高次谐波产生提供了前所未有的可能性。在此，我们将这些要点结合起来，展示了利用偏振匹配激发场实现圆偏振高次谐波产生，用于表面手性电子特性的光谱分析。我们的方法分别针对二氧化硅和氧化镁表面的结构螺旋度和终止介导的铁磁序展示了其灵敏度。现在，从固体样品发出的圆偏振辐射能够将手性等基本对称特性添加到固体强场光谱学的手段中。连同其固有的时间（飞秒）分辨率和非共振宽带光谱，凝聚态物质高次谐波的偏振控制能够阐明表面、埋层或薄膜的超快和强场动力学。
