Tuning the high-order harmonic lines of a Nd:Glass laser for soft x-ray laser seeding

Taking advantage of the non-adiabatic blue-shift of high-order harmonics generated by a fixed frequency Nd:Glass laser system, we are able to report more than 50 % coverage of the XUV spectral range between 18 nm and 35 nm. The generated harmonic lines are capable of seeding Ni-like Y, Zr and Mo soft x-ray lasers and others.

An Improved Double-Pulse Non-Normal Incidence Pumping Geometry for Transient Collisionally Excited Soft X-Ray Lasers

An optimized pumping geometry for transient collisionally excited soft X-ray lasers is presented, similar to the geometry proposed by [1]. In contrast to usual approaches, where a nanosecond pre-pulse is assumed to provide the optimal plasma preparation and a picosecond pulse performs the final heating- and excitation process, two pulses of equal duration in the range around 10 picoseconds are applied. Both pulses are produced in the front end of the CPA pump laser. They are focused onto the target with the same spherical mirror under non-normal incidence geometry, optimized for efficient traveling wave excitation for the main-pulse. A first experiment was performed on Ni-like palladium (14…

Double-pulse single-beam grazing-incidence pumping

The paper reports on the optimization of a table-top nickel-like molybdenum transient collisionally excited soft x-ray laser (SXRL) at 18.9 nm, performed by double-pulse single beam grazing incidence pumping (DGRIP) [1]. This scheme allows for the first time the full control of the pump laser parameters including the pre-pulse duration, optimally generating the SXRL amplifier under grazing incidence. The single beam geometry of collinear double-pulse propagation guarantees the ideal overlap of the pre- and main pulse from shot to shot, resulting in a more efficient, highly stable SXRL output. SXRL energies up to 2.2 µJ are obtained with a total pump energy less than 1 J for several hours at…

Short-wavelength soft-x-ray laser pumped in double-pulse single-beam non-normal incidence

We demonstrated a $7.36$ nm Ni-like samarium soft-x-ray laser, pumped by $36$ J of a neodymium:glass chirped-pulse amplification laser. Double-pulse single-beam non-normal-incidence pumping was applied for efficient soft-x-ray laser generation. In this case, the applied technique included a single-optic focusing geometry for large beam diameters, a single-pass grating compressor, traveling-wave tuning capability, and an optimized high-energy laser double pulse. This scheme has the potential for even shorter-wavelength soft-x-ray laser pumping.

LASERIX: an open facility for developments of Soft X-ray and EUV lasers and applications

In this paper we report the perspectives of the development of the XUV laser sources and applications using High-power laser facilities. We focus our paper on the present status of the French LASERIX facility and more especially about its role in the development of the XUV laser sources considering the French "Institut de la Lumiere Extreme " (ILE) and the potential European project Extreme Light Infrastructure (ELI). Finally, we present the scientific perspectives of X-ray laser sources developments using these laser facilities.

Versatile High-Energy and Short-Pulse Operation of PHELIX

PHELIX (Petawatt High Energy Laser for Heavy Ion Experiments) is a hybrid Ti:Sapphire / Nd:Glass laser system using large aperture amplifiers from the former Nova and Phebus laser systems at Livermore and Limeil, respectively, designed to offer pulse energies in access of 2 kJ and output power in the petawatt range. It is aiming mainly on combined experiments in plasma physics [2] and atomic physics [3] together with the GSI accelerator facility, and in preparation for the new FAIR facility for antiproton and ion research. Both nanosecond and sub-picosecond pulses can be supplied. Presently pulse energies up to 500 J are used, at pulse durations between 2 and 25 ns. Compressed pulses down t…

Stable and long-time operation of a soft x-ray laser for user applications experiments

LASERIX is a high-power laser facility leading to High-repetition-rate XUV laser pumped by Titanium:Sapphire laser. The aim of this laser facility is to offer Soft XRLs in the 30-7 nm range and auxiliary IR beam that could also be used to produce synchronized XUV sources. This experimental configuration highly enhances the scientific opportunities of the facility, giving thus the opportunity to realize both X-ray laser experiments and more generally pump/probe experiments, mixing IR and XUV sources. In this contribution, the main results concerning both the development of XUV sources(X-Ray lasers and HHG sources) and their use for applications are presented.

Tuning of High-Order Harmonics for Soft X-Ray Laser Seeding

Within this work we present results of an experimental campaign studying the influence of the adiabatic and non-adiabatic blue shift on high-order harmonic (HH) radiation spectra. The results demonstrate that we are able to spectrally tune the HH radiation to cover more than 50% of the spectrum between 17 nm and 35 nm, paving the way to performing injection-seeded soft X-ray laser (SXRL) experiments with Mo, Zr and Y.

Laser driven parametric amplification in the xuv and soft-x-ray spectral range

We present the first experimental realization of a new x-ray laser scheme based on strong-field parametric amplification of high-order harmonic radiation. With a simple semi-classical model, we can identify the most important experimental parameters, the spectral range and the small signal gain in gases. Using a single amplifier stage a small signal gain of 8000 has been obtained in Argon for the spectral range of 40-50 eV, using 350 fs, 7 mJ pulses at 1.05 µm. In Helium, we observed a small signal gain of 280 around 300 eV using 6 fs, 1.5 mJ pulses at 800 nm.

Laser-driven amplification of soft X-rays by parametric stimulated emission in neutral gases

The high-order harmonics of short laser pulses created in a nonlinear medium are a useful source of extreme-ultraviolet and soft-X-ray radiation. A newly discovered phenomenon that amplifies this emission even further could improve the efficiency of short-wavelength light sources.

Laser driven X-ray parametric amplification in neutral gases—a new brilliant light source in the XUV

Abstract In this paper we present the experimental setup and results showing a new type of strong-field parametric amplification of high-order harmonic radiation. With a simple semi-classical model, we can identify the most important experimental parameters, the spectral range and the small signal gain in gases. Using a single stage amplifier, a small signal gain of 8000 has been obtained in argon for the spectral range of 40–50 eV, using 350 fs, 7 mJ pulses at 1.05 μm. An outlook for an experiment employing a double stage gas system will be given.

Demonstration of an efficient pumping scheme for a 7.36-nm Ni-like samarium soft x-ray laser

The demonstration of a 7.36 nm Ni-like Sm soft x-ray laser pumped by 36 J of a Nd:glass chirped pulse amplification laser is presented. Double-pulse single-beam non-normal incidence pumping was applied for the efficient soft x-ray laser generation. Here the applied technique included a new single optic focusing geometry for large beam diameters, a single-pass grating compressor traveling-wave tuning capability and an optimized high energy laser double-pulse. This scheme has the potential for even shorter wavelength soft x-ray laser pumping.

Characterization of a 10Hz double-pulse non-normal incidence pumped transient collisional Ni-like molybdenum soft x-ray laser for applications

Stable and reliable operation of a nickel-like molybdenum transient collisional soft x-ray laser at 18.9 nm demonstrated and studied with a 10Hz Ti:sapphire laser system proves the suitability of the double-pulse non-normal incidence pumping geometry for table-top high repetition soft x-ray lasers and broadens the attractiveness of x-ray lasers as sources of coherent radiation for various applications. X-ray laser emission with pulse energies well above 1 μJ is obtained for several hours at 10Hz repetition-rate without re-alignment under optimized double pumping pulse parameters including energy ratio, time delay, pulse duration and line focus width.

Reply to 'The super-quadratic growth of high-harmonic signal as a function of pressure'

Ambient-temperature high-pressure-induced ferroelectric phase transition in CaMnTi2O6

Physical review / B 96(9), 094101 (2017). doi:10.1103/PhysRevB.96.094101

Strong field amplification of XUV: phase matching aspects

The dependence of the yield of high-order harmonic generation (HHG) on several important experimental parameters has been successfully modeled in the last 20 years by taking into account the single atom response and propagation effects. We extended this description by adding a stimulated emission process and named it x-ray parametric amplification (XPA). Beyond the super-quadratic increase of the XUV signal, which can be explained only in a limited pressure range by HHG theory, other observed characteristics like exponential growth, gain narrowing, strong blue-shift, beam divergence, etc. and their dependence on laser intensity and gas pressure can be explained accurately only by the new XP…

A Non-Normal Incidence Pumped Ni-Like Zr XRL for Spectroscopy of Li-Like Heavy Ions at GSI/FAIR

One of the unique features of the PHELIX laser installation is the combination of the ultra-high intensity laser with the heavy-ion accelerator facility at GSI and its planned extension FAIR. Due to this combination, PHELIX will allow novel investigations in the fields of plasma physics, atomic physics, nuclear physics, and accelerator studies. An important issue within the scientific program is the generation of high quality x-ray laser beams for x-ray laser spectroscopy of highly-charged ions. The long range perspective is the study of nuclear properties of radioactive isotopes within the FAIR [1] project. A novel single mirror focusing scheme for the TCE XRL has been successfully impleme…

Perspectives of XUV sources development on LASERIX facility, ILE, and ELI

In this paper we present the perspectives of the development of the XUV laser sources using High-power laser facilities. We focus our paper on the present statuts of the LASERIX facility and especially its role in the development of the XUV laser sources considering the French "Institut de la Lumiere Extreme" (ILE) and the potential European project Extreme Light Infrastructure (ELI).