Single-shot complete spatiotemporal measurement of terawatt laser pulses

Abstract

We demonstrate, for the first time, a single-shot, complete spatiotemporal measurement of pulses from a terawatt-scale, multi-stage-amplified, low repetition-rate laser source. The ultrashort pulse electric field, E(x,y,z,t), is spatiotemporally complex due to distortions that accrue from multiple chirped-pulse amplifiers, which requires a complete characterization. Meanwhile, the instability of the laser source introduces field profiles that vary significantly from pulse to pulse, which, together with the low repetition-rate (15 shots/hour), requires the use of a single-shot measurement technique. To accomplish the measurements, we used a wavelength-multiplexed, digital-holographic technique called Spatially and Temporally Resolved Intensity and Phase Evaluation Device: Full Information from a Single Hologram, specially tailored to measure picosecond pulses at a wavelength of about 1 μm. Specifically, individual pulses from the compact multipulse terawatt laser were measured, with up to 0.3 J per shot of energy and ∼2 ps pulse durations, at 1052 nm. With these measurements, we characterized several major spatiotemporal distortions that affect the peak intensity at the laser focus, as well as the pulse-shape instability on a shot-to-shot basis. Our technique allows detailed diagnosis of laser pulses (especially high-order spatiotemporal distortions) and provides straightforward four-dimensional animations of pulse propagation to a focus.

Investigation of hard x-ray emissions from terawatt laser-irradiated foils at the Matter in Extreme Conditions instrument of the Linac Coherent Light Source

“…When possible, it 2022 JINST 17 T04004 is preferable to measure laser parameters at full energy. Recent work has also demonstrated that it is possible to fully reconstruct the electric field of ultrashort high-power pulses on a single-shot basis, providing a more accurate characterization of the on-target laser intensity and thus improved benchmarks for the radiation levels produced in high-power laser-target interactions [26].…”

Single-shot compressed optical field topography

“…Previously, multi-shot techniques scanning spatial positions 37 or temporal delays [38][39][40] can measure the optical field of femtosecond laser pulses with negligible pulse-to-pulse variations. Single-shot techniques "multi-spectrally" measure spatial profiles of an optical field in a few wavelength channels 5,6,41 . However, as far as we know, drawing a real 3D map in a single shot (not a series of 2D slices) for the optical field of a femtosecond laser pulse is still challenging.…”

“…Capturing 3D optical field information with a twodimensional (2D) sensor in single-shot is challenging. A quasi-3D solution is to sample a finite number of discrete 2D spectral or temporal "slices" of the 3D ultrafast scenes, such as imaging with chirped multispectral components [5][6][7] or at a few specific time delays 8,9 . However, the multi-slice stack of 2D images cannot resolve complicated 3D spatiotemporal structures of an ultrafast optical field with intense amplitude or phase modulations.…”

Spatiotemporal pulse characterization with far-field beamlet cross-correlation

“…In parallel to state-of-the-art temporal metrology development [18][19][20], significant progress has been made in measuring STC during the last decades. The development of spatio-temporal metrology is well summarized in reviews [6,21,22], while the cutting edge work is presented in recent papers [23][24][25]. Some of these state-of-the-art techniques provide the complete spatiotemporal characterization of near-visible femtosecond laser beams.…”