Investigation of Time-Delayed Probing of Ultrafast Laser Generated Plasma Gratings Using Combined 1D1V Kinetic Modeling and Light Scattering Simulations

This work investigates the excitation, evolution, and optical interrogation of transient electron plasma gratings created by crossed ultrashort laser pulses in low temperature plasmas. Our analysis utilizes a weakly coupled modeling framework that combines a 1D1V direct kinetic simulation of grating excitation on a frozen ion background with time-dependent light-scattering calculations in the slowly varying envelope approximation. Simulations are performed to explore how key dimensionless parameters affect the signal pulse amplitude and spectrum and to examine the conditions under which coherent scattering from the induced plasma grating can be exploited as a diagnostic of local plasma properties. Calculations are performed over a range of parameters. The results indicate that three key criteria must be satisfied to produce long-lived electron plasma gratings: operation in the collective regime, pump pulse durations shorter than the electron plasma period, and weak collisional damping. Provided these conditions are met, we find the initial perturbation evolves into a self-propagating electron plasma wave that persists for many plasma oscillation periods after the pump pulses exit the interaction region. Outside this regime, the density modulation decays rapidly, limiting its diagnostic utility. Scattering simulations demonstrate that the temporal and spectral characteristics of the probe-pulse-induced signal encode the plasma grating dynamics, with probe pulse duration governing the balance between instantaneous grating measurements and time-integrated sensitivity to plasma oscillations and damping. Under representative low-temperature plasma conditions, single-shot photon yields on the order of tens to hundreds are predicted despite the low reflectivity of underdense plasma gratings. Practical considerations indicate that time- delayed probing of the grating decay, rather than probing during pump pulse overlap, provides the most robust pathway for isolating plasma-specific signals from competing interferences.