Time-resolved probing and modeling of optical signatures of ultrashort-pulse laser spallation and phase explosion in iron-nickel targets

作者：Chaobo Chen, Maximilian Spellauge, David Redka, Ramon Auer, Carlos Doñate‐Buendía, Stephan Barcikowski, Bilal Gökce, H. Huber, Leonid V. Zhigilei · 发表于：Physical review. B./Physical review. B · 年份：2025 · DOI：10.1103/physrevb.111.174301 · 被引用次数：14 · 研究领域：Laser-induced spectroscopy and plasma、Laser Material Processing Techniques、Ocular and Laser Science Research

Time-resolved microscopy is an established technique for probing the dynamics of laser ablation, thus enabling the exploration of material behavior under extreme conditions produced by laser excitation. Decoding the time-resolved data on the rapid variation of optical properties of a material undergoing nonequilibrium phase decomposition and ejection, however, presents a significant challenge. In this paper, a closely integrated computational and experimental study of laser ablation of FeNi targets is used to establish direct links between the dynamics of laser ablation and the evolution of optical signal in pump-probe experimental measurements. The experiments and large-scale atomistic simulations are performed for a range of fluences covering the onset of material ejection at the threshold for photomechanical spallation and the transition to the phase explosion regime of laser ablation. The connections between the simulations and experiments are established through numerical modeling of the interaction of an electromagnetic wave representing the experimental probe laser pulse with transient states of the ablation plume predicted in the atomistic simulations. The combined modeling and experiments have revealed a complex interplay of processes defining the transient optical properties of the emerging ablation plume, including the oscillations of reflectance due to the interference of parts of the probe pulse reflected from the spalled layer and the newly formed surface of the...