Spatio-temporal characterization of a petawatt laser using deterministic speckle patterns

We present a deterministic method for the spatio-spectral characterization of intense ultrashort laser pulses via farfield speckle analysis.By mapping vacuum propagation to a linear forward model, we replace slow, error-prone iterative algorithms with a direct least-squares minimization.This enables high-speed retrieval of spectrally resolved wavefronts with rigorous uncertainty quantification.Demonstrated at the ATLAS-3000 petawatt facility, our in situ architecture utilizes only a pinhole mask for both attenuation and speckle generation.By eliminating complex downstream optics and minimizing systematic errors, this approach provides a robust, real-time diagnostic essential for the optimization of high-intensity lasers.