Laser pulse compression by a density gradient plasma for exawatt to zettawatt lasers

Abstract

We propose a new method of compressing laser pulses to ultrahigh powers based on spatially varying dispersion of an inhomogeneous plasma. Here, compression is achieved when a long, negatively frequency-chirped laser pulse reflects off the density ramp of an over-dense plasma slab. As the density increases longitudinally, high-frequency photons at the leading part of the laser pulse penetrate more deeply into the plasma region than lower-frequency photons, resulting in pulse compression in a similar way to that by a chirped mirror. Proof-of-principle simulations performed using particle-in-cell simulation codes predict compression of a 2.35 ps laser pulse to 10.3 fs-a ratio of 225. As plasma is robust and resistant to damage at high intensities-unlike solid-state gratings commonly used in chirped-pulse amplification-the method could be used as a compressor to reach exawatt or zettawatt peak powers. Researchers propose a laser pulse compression method for exawatt to zettawatt lasers based on spatially varying dispersion of an inhomogeneous plasma. This may enable, for example, pulse compression of a laser pulse from 2.35 ps to 10.3 fs. The approach is robust at high intensities.