O. Guilbaud

Temporal characterization of a picosecond extreme ultraviolet laser pumped in grazing incidence

We report an experimental study of the temporal duration of a transient pumping extreme ultraviolet (XUV) laser emitted at 18.9 nm, using an ultrafast x-ray streak camera. We have investigated the shot-to-shot reproducibility of the pulse duration, as well as its behaviour as a function of several pumping parameters. Our results show that the pulse duration increases slowly with the pump pulse duration, in agreement with previous observations performed in a different geometry. The angle of the pump laser relative to the target surface also affects the XUV laser duration in a measurable way.

Evidence of partial temporal coherence effects in the linear autocorrelation of extreme ultraviolet laser pulses

We study how the degree of temporal coherence of plasma-based extreme ultraviolet lasers operated in the amplification of the spontaneous emission mode is encoded in the shape of the linear autocorrelation function, which is obtained from the variation of the fringe visibility while varying the delay in a variable path-difference interferometer. We discuss the implications of this effect when the technique is used to infer the spectral properties of the source. Our numerical simulations, based on a partial coherence model developed by other authors for x-ray free electron lasers, are in good agreement with previously reported sets of measurements, illustrating similar statistical properties for both sources.

Recent progress on the LASERIX facility

The LASERIX facility provides coherent and short soft x-ray beams for scientific applications. The beams are generated through high intensity laser interaction with matter using two different schemes, plasma based soft x-ray lasers, and high order laser harmonic generation. We describe in this communication the present status of the facility. The LASERIX beamtime has been recently opened to external users. We present two typical experiments performed in that context with the facility. The first one is dedicated to the fundamental study of the plasma based soft x-ray laser, whereas the second uses the existing beam to study irradiation induced dammage in DNA samples. We present also the development performed on the soft x-ray laser source to improve its stability and high repetition rate operation.

Near-field imaging of Ni-like silver transient collisional x-ray laser

We review our recent progress in the development of transient x-ray lasers and of their application to plasma diagnostic. The first observation of C-ray laser emission at the new PHELIX-GSI facility is reported. This TCE X-ray laser will be a promising tool for heavy-ion spectroscopy. We then present the main results obtained at the LULU-CPA facility with a compact high-resolution X-UV imaging device. This device was used to investigate the spatial source structure of the Ni-like silver transient X-ray laser under different pumping conditions. The key-role of the width of the background laser pulse on the shape of the emitting aperture is demonstrated. Finally the imaging device was used as an interference microscope for interferometry probing of a laser-produced plasma. We describe this experiment performed at APRC-JAERI.

Saturated and Short Pulse Duration X‐Ray Lasers

The basis of a model of the relationship between gain and output laser intensity is reviewed and the measurement of the duration of X‐ray lasing with a streak camera with 700 fs temporal resolution is described. Combined with a temporal smearing due to the spectrometer employed, we have measured X‐ray laser pulse durations for Ni‐like silver at 13.9 nm and Ne‐like nickel at 23.1 nm with a total time resolution of 1.1 ps. An extension of the model is shown to consistently relate the measured X‐ray laser pulse duration to estimates of the gain duration obtained by temporally resolving resonance line emission from states near in energy to the upper lasing level.

Longitudinal compression and transverse matching of electron bunch for external injection LPWA at ESCULAP

We present theoretical and numerical studies of longitudinal compression and transverse matching of electron bunch before injecting into the Laser-plasma Wake Field Accelerator (LWFA) foreseen at the ESCULAP project in ORSAY. Longitudinal compression is performed with a dogleg chicane, the chicane is designed based on theory of beam optics, beam dynamics in dogleg is studied with ImpactT and cross checked with CSRtrack, both 3D space charge (SC) and coherent synchrotron radiation (CSR) effects are included. Simulation results show that the energy chirp at the dogleg entrance should be smaller than the nominal optic design value, in order to compensate the negative energy chirp increase caused by longitudinal SC, while CSR can be ignored in our case. With an optimized configuration, the electron bunch (

Atomic and Plasma Physics Software and Databases for the Simulation of Short Wavelength Sources

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LASERIX: An open facility for developments of soft X-ray and EUV lasers and applications

10MeV, 10pC) is compressed from 0.9ps RMS to 70fs RMS (53fs FWHM), with a peak current of 152A. Transverse matching is realized with a doublet and a triplet, they are matched with Madx and the electron bunch is tracked with ImpactT, simulation results show little difference with the nominal design values, that is due to the SC effect. Finally, by simply adjusting the quadrupole strength, a preliminary optimized configuration has been achieved, that matches the Courant-Snyder (C-S) parameters to

Caractérisation spatio-temporelle d'un laser XUV injecté

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Temporal Coherence and Spectral Linewidth of a Seeded Soft X-Ray Laser Pulse

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