Replication Data for: Attosecond metrology of vacuum-ultraviolet high-order harmonics generated in semiconductors via laser-dressed photoionization of alkali metals

Semiconductor crystals driven by strong mid-infrared pulses offer advantages for studying many-body physics and ultrafast optoelectronics via high-harmonic generation. While the process has been used to study solids in the presence strong mid-infrared fields, its potential as an attosecond light source is largely underexplored. We demonstrate that high-harmonics emitted from zinc-oxide crystals produce attosecond pulses, measured through spectroscopy of alkali metals. Using a cross-correlation approach, we photoionize Cesium atoms with vacuum-ultraviolet high-harmonics in the presence of a mid-infrared laser field. We observe oscillations in the photoelectron yield, originating from the instantaneous polarization of atoms by the laser field. The phase of these oscillations encodes the attosecond synchronization of the high-harmonics and is used for attosecond pulse metrology. This source opens new spectral windows for attosecond spectroscopy, enabling studies of bound-state dynamics in natural systems with low ionization energies, while facilitating the generation of non-classical entangled light states in the visible-VUV.

强中红外脉冲驱动的半导体晶体，可借助高次谐波产生（high-harmonic generation）技术，为多体物理与超快光电子学的研究提供有力支撑。尽管该过程已被用于探究强中红外场环境下的固体材料，但其作为阿秒光源的潜力在很大程度上仍未得到充分发掘。我们证实，氧化锌晶体辐射出的高次谐波可产生阿秒脉冲，并通过碱金属光谱学完成了相关测量。我们采用互相关方法，在中红外激光场存在的条件下，利用真空紫外（vacuum-ultraviolet）高次谐波对铯原子实施光电离。我们观测到光电子产额存在振荡现象，该振荡源于激光场对原子的瞬时极化作用。这些振荡的相位携带着高次谐波的阿秒同步信息，可被用于阿秒脉冲计量研究。该光源为阿秒光谱学研究开辟了全新的光谱窗口，既能够探究电离能较低的天然系统中的束缚态动力学过程，也可实现在可见光-真空紫外波段生成非经典纠缠光态。