Spatiotemporal characterization of a PW laser

Abstract

Measurement and control of the spatiotemporal characteristics of ultrahigh-power lasers have been explored. As the spatiotemporal electric field contains spatiotemporal couplings that can degrade the laser intensity achievable from a high-power laser, the rigorous spatiotemporal characterization of a laser electric field is critical in accomplishing the best laser performance. The spatiotemporal coupling of the optical parametric chirped pulse amplification amplifier, adopted as the frontend amplifier of the 4 PW laser, was investigated by measuring the induced angular dispersion from an optical parametric chirped pulse amplification amplifier, along with a theoretical analysis of the induced angular dispersion. In order to measure the full spatiotemporal electric field of a laser pulse, we have developed a novel characterization method by devising a spectrally resolved wavefront sensing device and applied it for the characterization of the spectrally resolved intensity and phase of a multi PW laser pulse. From the reconstruction, it was found that the spatiotemporal distortion could reduce the focused laser intensity by 15%, compared to the case of an ideal diffraction-limited and transform-limited laser pulse. The advantage of this characterization technique is that spatiotemporal coupling can be measured without pulse compression. Consequently, this technique can be utilized to locate the optical component inducing the spatiotemporal coupling in the 4 PW beamline and to eliminate the spatiotemporal coupling; this characterization technique can make crucial contributions in optimizing the performance of the 4 PW laser so as to reach the maximum achievable laser intensity, paving the pathways for strong-field physics research.