Wavefront improvement in an injection-seeded soft x-ray laser based on a solid-target plasma amplifier

Includes bibliographical references (page 4013).The wavefront of an injection-seeded soft x-ray laser beam generated by amplification of high-harmonic pulses in a λ=18.9 nm molybdenum plasma amplifier was measured by a Hartmann wavefront sensor with an accuracy of λ/32 root mean square (rms). A significant improvement in wavefront aberrations of 0.51±0.03λ rms to 0.23±0.01λ rms was observed as a function of plasma column length. The variation of wavefront characteristic as a function time delay between the injection of the seed and peak of soft x-ray amplifier pump was studied. The measurements were used to reconstruct the soft x-ray source and confirm its high peak brightness

Single shot XUV nanoimaging using an intense femtosecond soft X-ray laser

We report the direct wavefront characterization of an intense ultrafast high-harmonic-seeded soft X-ray laser (λ=32.8 nm) depending on the arrival time of the seed pulses by high-resolution ptychographic imaging and subsequently perform single-shot nanoscale imaging

Single shot XUV nanoimaging using an intense femtosecond soft X-ray laser

We report the direct wavefront characterization of an intense ultrafast high-harmonic-seeded soft X-ray laser (λ=32.8 nm) depending on the arrival time of the seed pulses by high-resolution ptychographic imaging and subsequently perform single-shot nanoscale imaging

Hard X Rays from Laser-Wakefield Accelerators in Density Tailored Plasmas

International audienceBetatron x-ray sources from laser-plasma accelerators reproduce the principle of a synchrotron at the millimeter scale. They combine compactness, femtosecond pulse duration, broadband spectrum, and micron source size. However, when produced with terawatt class femtosecond lasers, their energy and flux are not sufficient to compete with synchrotron sources, thus limiting their dissemination and its possible applications. Here we present a simple method to enhance the energy and the flux of betatron sources without increasing the laser energy. The orbits of the relativistic electrons emitting the radiation were controlled using density tailored plasmas so that the energetic efficiency of the betatron source is increased by more than one order of magnitude

Table-top extreme ultraviolet second harmonic generation

International audienceThe lack of available table-top extreme ultraviolet (XUV) sources with high enough fluxes and coherence properties has limited the availability of nonlinear XUV and x-ray spectroscopies to free-electron lasers (FELs). Here, we demonstrate second harmonic generation (SHG) on a table-top XUV source by observing SHG near the Ti M 2,3 edge with a high-harmonic seeded soft x-ray laser. Furthermore, this experiment represents the first SHG experiment in the XUV. First-principles electronic structure calculations suggest the surface specificity and separate the observed signal into its resonant and nonresonant contributions. The realization of XUV-SHG on a table-top source opens up more accessible opportunities for the study of element-specific dynamics in multicomponent systems where surface, interfacial, and bulk-phase asymmetries play a driving role

Towards a Free Electron Laser Using Laser Plasma Acceleration

International audienceSince the laser invention, the advent of X-ray Free Electron Lasers (FEL) half a century later, opens new areas for matter investigation. In parallel, the spectacular development of laser plasma acceleration (LPA) with several GeV beam acceleration in an extremely short distance appears very promising. As a first step, the qualification of the LPA with a FEL application sets a first challenge. Still, energy spread and beam divergence do not meet the state-of-the-art performance of the conventional accelerators and have to be manipulated to fulfill the FEL requirement. We report here on the undulator spontaneous emission measured after a transport manipulation electron beam line, using variable permanent magnet quadrupoles of variable strength for emittance handing and a demixing chicane equipped with a slit for the energy spread. Strategies of control electron beam position and dispersion have been elaborated. The measured undulator radiation provides an insight on the electron beam properties