Single-Shot, Spatio-Temporal Metrology of Relativistic Plasma Optics

Ultrahigh peak power femtosecond laser pulses create extreme states and are currently being probed with great interest. Plasma optics have been proposed for shaping and amplifying high-power pulses, but they are subject to huge modulations and fluctuations due to the very nature of excitation at high intensities. Multidimensional characterization (spatial, temporal, and spectral) and control of relativistic plasma dynamics and their impact on the spatio-temporal structure of intense femtosecond pulses are therefore essential yet extremely difficult to achieve, particularly at the low repetition rates typical at 100s terawatt to petawatt. Here, we present a single-shot, two-dimensional (2D) spatio-temporal and spatio-spectral measurement of such pulses based on spectral interferometry. We reconstruct the 3D temporal structure of the laser pulse simultaneously resolving the complex plasma dynamics. We demonstrate our method by measuring the sub-picosecond evolution of a relativistically hot plasma deep within a solid. Our measurements reveal that different spatial regions of the plasma surface move differently yet exhibit a collective behavior globally. This all-optical measurement technique can capture 2D spatio-temporal effects within pulses spanning the terawatt to petawatt range, all in a single shot, enabling further progress in high-intensity laser pulse technology.