Modeling and Single-Shot Visualization of High-Intensity Femtosecond Laser-Matter Interactions in Solids

Plasma formation under intense laser irradiation significantly alters the dielectric properties of solid materials, with the electron collision time and plasma density being key factors governing optical responses such as reflection, absorption, and phase modulation [1]. We employ single-shot frequency-domain holography (FDH) [2-4] to measure amplitude and phase changes of probe beam in thin glass samples exposed to strong pump fields, allowing for spatio-temporally-resolved visualization of the electron collision time and plasma density. We also present a self-consistent simulation framework that couples the time-domain beam propagation method (TDBPM) [5] with two-temperature model (TTM), enabling the calculation of the dynamic electron collision time and plasma density during laser-plasma interactions. Both experimental and simulation results reveal clear spatio-temporal evolution of the electron collision time and plasma density correlated with laser intensity. This work provides new insight into ultrafast laser-induced plasma dynamics and offers a quantitative method to characterize transient optical properties in strong-field interactions.

[1] G. C. Nagar et al., Communications Physics 4, 96 (2021); [2] S. P. Le Blanc et al., Opt. Lett. 56, 764-766 (2000); [3] D. Dempsey et al., Opt. Lett. 45, 1252-1255 (2020); [4] D. Dempsey et al., Opt. Commun. 545, 129669 (2023); [5] J. Shibayama et al., Journal of Lightwave Technology 23, 2285 (2005).