Intense THz fields can be used to excite specific low-frequency modes in condensed matter or drive confined currents in nano-structured arrays, paving the way for a new class of optoelectronic devices. The long wavelength enables spatially confined field enhancement due to interaction with metallic structures and interference effects at dielectric interfaces. We use THz photoelectron streaking for the polarization-sensitive reconstruction of all electric field components at dielectric and metallic interfaces. This is realized in a THz/x-ray pump–probe experiment where x-ray emitted photoelectrons probe the effective THz field in close surface proximity. We observe distinct differences in the THz response of a nano-structured Pt thin film and a Pt(111) bulk crystal, in particular for the parallel field component. Simulations of the nanoscale spatial field modulation at metallic islands on the thin film provide design parameters for different sensitivity regimes with respect to local fields.

中文翻译：

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电介质界面处瞬态局部THz场的极化敏感重建

强大的太赫兹场可用于在凝聚态物质中激发特定的低频模式，或驱动纳米结构阵列中的受限电流，从而为新型光电器件铺平了道路。由于与金属结构的相互作用以及介电界面处的干扰效应，长波长可以实现空间受限的场增强。我们使用太赫兹光电子条纹对介电和金属界面上的所有电场分量进行极化敏感的重建。这是在THz / x射线泵浦探针实验中实现的，在该实验中，x射线发射的光电子在接近表面的位置探测有效THz场。我们观察到纳米结构的Pt薄膜和Pt（111）块状晶体在THz响应中的明显差异，特别是对于平行场分量。