Space-time characterization of laser plasma interactions in the warm dense matter regime

Abstract

Laser plasma interaction experiments have been performed using an fs Titanium Sapphire laser. Plasmas have been generated from planar PMMA targets using single laser pulses with 3.3 mJ pulse energy, 50 fs pulse duration at 800 nm wavelength. The electron density distributions of the plasmas in different delay times have been characterized by means of Nomarski Interferometry. Experimental data were compared with hydrodynamic simulation. First results to characterize the plasma density and temperature as a function of space and time are obtained. This work aims to generate plasmas in the warm dense matter (WDM) regime at near solid-density in an ultra-fast laser target interaction process. Plasmas under these conditions can serve as targets to develop X-ray Thomson scattering as a plasma diagnostic tool, e.g., using the Vacuum ultraviolet (VUV) free-electron laser (FLASH) at Dentsches ElektronenSynchrotron (DESY) Hamburg.

XUV spectroscopic characterization of warm dense aluminum plasmas generated by the free-electron-laser FLASH

“…Experimentally, the difficulty in producing WDM with a sufficient volume and lifetime for experimental studies is a challenge (Cao et al, 2007). Further, sophisticated methods such as X-ray scattering have undergone both theoretical and experimental developments (Lee et al, 2002;Riley et al, 2007;Fortmann et al, 2009;Glenzer & Redmer, 2009) in the last decade to probe such dense plasmas.…”

Optical, x-ray and microwave diagnostics

“…It can be useful to get information on the influence of target geometry on the laser-matter interaction and the possible plasma space-time evolution. The interaction conditions can be investigated via imaging and spectroscopy at the fundamental and the second harmonic of the laser frequency, both in the forward and backward direction [2].In such a way the conditions suitable for electron acceleration close to the propagation axis, can be checked as well as their reproducibility.Laser interferometry, based on the analysis of the fringe structures originated by a probe beam crossing the plasma cloud, is a versatile tool for estimating the plume density at earlier times [3]. It permits a very accurate determination of the electron density and is particularly used in the first instants of plume expansion, when the strong continuum, associated with bremsstrahlung and recombination emissions, does not allow a clear detection of the shape of the emission line.…”

An extreme ultraviolet Michelson interferometer for experiments at free-electron lasers

“…This scheme can be used for the time-resolved observation of plasma plumes expanding from laser-irradiated solids. 32,34 Since the critical density n c = ω 2 0 m/e 2 for XUV radiation is greater than 10 24 cm −3 , our method allows studying solid-density matter, while for optical light propagation is limited to free-electron densities of n c < 10 21 cm −3 . Here, ω is the laser angular frequency, 0 is the vacuum permittivity, and e is the electron charge.…”