Effect of high order spectral phase shaping of ultra-intense laser pulses on X-ray generation

Although the generation of ultra-intense laser pulses (>10²⁰ W.cm^-2) has become routine for many high intensity laser facilities around the world, optimizing the generation of laser-driven charged particles and x-rays from their interaction with solid matter is still a challenging process. Pulse energy, duration and chirp are usually the main laser parameters that are varied when carrying out studies of this type. Here, we investigate the systematic modification of high order spectral phase to produce varying pulse shapes of ultra-intense laser pulses and study their effects on the acceleration of charged particles and x-rays.

X-ray characterization was carried out using the ultra-compact x-ray spectrometer (UCXS), a high-repetition-rate-capable broadband X-ray diagnostic that utilizes Ross pair and step wedge filtration in combination with a scintillator and sCMOS camera to measure X-rays >3 keV [1]. Results will be shown from a high-repetition-rate (0.1 Hz) experimental campaign on the ALEPH laser at Colorado State University, where the group delay dispersion (GDD) and third order dispersion (TOD) were varied to change the delivered pulse shape. We will show the effect on X-ray generation (distribution temperature and flux), and discuss next steps for secondary source optimization.