Arnold Migus

Arnold Migus
École Polytechnique

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260
Publications
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Publications

Publications (260)
Article
During the last meeting of the seminar “The European Adventure of the CNRS”, Pierre Papon and Arnold Migus, both former General Directors of the National Center for Scientific Research, provide a picture of European research from the end of the Second World War to the very beginning of the 2010’s. By mentioning its successes and setbacks, they poin...
Chapter
Ultra intense laser chains exhibit large amounts of spatial and temporal aberrations which degrade the quality of the beam delivered by the source. These aberrations arise from the thermal lensing due to the efficient pumping of the gain media. Also, the aberrations of the optical components as well as the group delay dispersion effects due to ultr...
Article
The total energy reflected from a silicon single crystal irradiated by a 100 femtosecond laser pulse is measured. We observe a plasma resonance at wavelengths of 620 nm and 310 nm indicating electron-hole densities higher than 1022 cm. The result are interpreted using a highly non linear theory. Very short relaxation times are observed and attribut...
Conference Paper
A Multi-Petawatt High-Energy laser coupled to the LIL (MPWHE-LIL) is under construction in the Aquitaine Region in France. This facility will be open to academic community. Nd:glass laser chain and Chirped Pulse Amplification (CPA) technique makes possible to deliver high energy. Optical Parametric Chirped Pulse Amplification (OPCPA) for pre-amplif...
Article
With the goal to set up a high average power Diode Pumped Solid State Laser (100 Joules/10 Hz/10 ns), the Laboratory for Use of Intense Laser (LULI) is now studying various solutions concerning the amplifier medium, the cooling, the pumping and the extraction architectures. In this paper, we present the last states of these developments and the sol...
Article
We present the Petawatt Laser facility project at LULI, from the front end diode-pumped regenerative amplifier, delivering 60 mJ at 1 Hz, to the main power amplifiers and compact compressor based on high-damage-threshold dielectric gratings. This facility will offer a unique combination of a Petawatt laser synchronized with a 1 kJ long-pulse laser,...
Article
This paper reviews the highlights of the high intensity laser-plasma experiments achieved with the six-beam and the 100 TW LULI laser facilities, as well as the progress of the LULI 2000 project. This covers fields of laser fusion, equations of state, hgih energy particle emission, atomic physics, X-ray production and laser developments.
Article
Full-text available
We have built a diode-pumped Nd:glass regenerative amplifier that is able to produce energies up to 20 mJ within a 470-fs pulse duration at a 1-Hz repetition rate. We obtained this amplifier by using specific intracavity components such as a phase mirror and a birefringent filter to generate a large spatial mode and a large spectral width.
Conference Paper
The LUCIA (French acronym for "Laser Ultra-Court Intenses, et Applications") laser system consists in an oscillator delivering around 1 Joule in about 10 ns, followed by a multipass two-heads amplifier stage. In our design, oscillator and amplifier stages are longitudinally pumped at 10 Hz with respectively 15 and 10 kW/cm<sup>2</sup> intensity wit...
Article
A l'aide d'une boucle d'optique adaptative basée sur une valve électro-optique adressée optiquement, nous pouvons maîtriser la répartition de l'intensité lumineuse au foyer d'une lentille. Nous l'avons appliquée pour augmenter la qualité de focalisation de notre chaîne 100-TW mais aussi afin d'obtenir une focalisation selon une ligne de long de l'a...
Article
Full-text available
We have developed a high-resolution programmable adaptive-optic device based on an optically addressed liquid-crystal electro-optic valve controlled by an achromatic three-wave lateral shearing interferometer. We apply this phase-only filter and loop to shape the far-field pattern of laser beams. As a first application, we theoretically compute and...
Conference Paper
Summary form only given. We have studied and demonstrated an all-optical amplitude and phase modulation scheme able to operate at frequencies above 100 GHz. This method relies on the adapted phase method which has previously allowed one to efficiently generate narrow bandwidth second harmonic and more recently fundamental or second harmonic program...
Conference Paper
Summary form only given. The control of amplitude and phase is now routinely achieved for high power repetitive lasers. By using an acousto-optic programmable dispersive filter (Dazzler®), one can simultaneously modulate pulse, amplitude and phase. Our 100 TW multi-glass amplifier laser starts with a Ti:sapphire oscillator, a stretcher and a regene...
Conference Paper
Summary form only given. We show that diode pumped Yb:YAG lasers are particularly good candidates for femtosecond pulse applications, because centimeter-scale size aperture YAG crystals are easily available, their heat generation is reduced relative to Nd:YAG and high power laser diodes are available at the required pump wavelength. We designed the...
Article
We show wave front correction of a 300 fs/60J laser pulse serie. This correction is based on an optically addressed liquid crystal optical valve (OASLM) which induces high resolution phase modulations. When performed before complete thermal relaxation of the laser Nd:glass amplifiers, this correction allows to increase the system repetition rate by...
Article
We experimentally demonstrate pure optical pulse picosecond shaping of narrow-bandwidth nanosecond pulses. The method used is based on the manipulation in the spectral domain of strongly chirped femtosecond pulses and on the use of either frequency addition or frequency difference.
Article
Since its creation, LULI has given an important contribution to laser plasma physics and Inertial Confinement Fusion studies. We will review some major results obtained these last two years with a 600 ps laser chain and with the recent 100-TW, 300fs ultra-intense laser chain. These result cover a wide spectrum of laser plasma physics research such...
Conference Paper
Summary form only given. For the last 15 years, diffraction gratings have been the key critical components of the chirped pulse amplification (CPA) technique. They can introduce a large dispersion on an optical short pulse without propagating through a dispersive medium. However, their limited damage threshold has led to limited compressed energy....
Conference Paper
Summary form only given. The characterization of ultrashort optical pulses is a useful tool for the optimization of chirped pulse amplification systems. The quality of the output pulse depends on many parameters, including the compensation of dispersion, nonlinear effects, and gain narrowing. Large systems now deliver pulses with peak powers in the...
Conference Paper
Summary form only given. Because of spatial phase aberrations, ultra-intense laser systems with peak power in the 10 TW-1 PW range are difficult to focus close to the diffraction limit. Reaching this goal is an important task when trying to get the highest possible intensities (typically>10<sup>21</sup> W/cm<sup>2</sup>). We previously demonstrated...
Conference Paper
Summary form only given. We have shown for the first time a phase and amplitude modulation and measurement at 1.05 μm on a 100 TW laser chain. Pulse cleaning and increase of the output spectral bandwidth has also been demonstrated. This kind of implementation should be successful in higher energy laser chains such as a PW source
Article
We report the photometric observation of a polychromatic laser guide star (PLGS) using the AVLIS laser at the Lawrence Livermore National Laboratory (LLNL). The process aims at providing a measurement of the tilt of the incoming wave front at a telescope induced by atmospheric turbulence. It relies on the two-photon coherent excitation of the 4D5/2...
Article
In the last few years, many solutions have been implemented to correct the wavefront of intense laser beams. Most of them use an adaptive mirror to achieve this correction. At LULI, we have developed in collaboration with Thomson-CSF a liquid-crystal optically addressed electro-optical valve (OAEOV) approach to induce phase shifts onto the beam. Co...
Conference Paper
Full-text available
We describe the current status of the ELP-OA project in which we try to demonstrate in practice that it is possible to measure the tilt of a wave front using only a polychromatic laser guide star and no natural guide star. The first phase of ELP-OA, consisting of feasibility experiments, has recently been completed successfully. This paper provides...
Article
Adaptive optics at astronomical telescopes aims at correcting in real time the phase corrugations of incoming wavefronts caused by the turbulent atmosphere, as early proposed by Babcock. Measuring the phase errors requires a bright source located within the isoplanatic patch of the program source. The probability that such a reference source exists...
Article
Full-text available
Adaptive optics at astronomical telescopes aims at correcting in real time the phase corrugations of incoming wavefronts caused by the turbulent atmosphere, as early proposed by Babcock. Measuring the phase errors requires a bright source located within the isoplanatic patch of the program source. The probability that such a reference source exists...
Conference Paper
Adaptive optics at astronomical telescopes aims at correcting in real time the phase corrugations of incoming wavefronts caused by the turbulent atmosphere, as early proposed by Babcock. Measuring the phase errors requires a bright source, which is located within the isoplanatic patch of the program source. The probability that such a reference sou...
Article
Full-text available
New techniques to produce spatiotemporal phase modulation without the use of electro-optic devices are pro-posed and discussed. By using the nonlinear second-order effect in crystal it is possible to change the ampli-tude modulation of a pump wave into the phase of a signal wave. To that end, we propose the use of a well-known cascading configurati...
Article
We report what is to our knowledge the first demonstration of a transient x-ray laser pumped by a 350-fs pulse in a traveling-wave irradiation geometry. For a 500-fs pump pulse the traveling-wave irradiation was found to have a strong effect on enhancing the Ni-like silver 4d-4p lasing emission at 13.9 nm. The signal enhancement was significantly l...
Article
We have implemented an adjustable traveling-wave method of excitation for the transverse pumping of laser media based on tilting one of the gratings of the compressor of a chirped pulse amplification [Opt. Commun. 56, 219 (1985)] (CPA) laser chain. We show that the only requirement to obtain the best locally compressed pulse is to slightly tilt and...
Article
Acousto-optic programmable dispersive filters (AOPDF) can compensate in real time for large amounts of group-delay dispersion. This feature can be used in chirped-pulse amplification femtosecond laser chains to compensate adaptively for dispersion. An analytical expression relating the group delay at the output of the AOPDF to the input acoustic si...
Article
We have implemented an adjustable traveling-wave method of excitation for the transverse pumping of laser media based on tilting one of the gratings of the compressor of a chirped pulse amplification [Opt. Commun. 56, 219 (1985)] (CPA) laser chain. We show that the only requirement to obtain the best locally compressed pulse is to slightly tilt and...
Article
Summary form only given. Precise temporal pulse shaping of optical pulses has become increasingly important in laser-matter interaction and applications. This is true at the femtosecond time scale for coherent control experiments as well as in the nanosecond time scale with inertial confinement fusion applications. In the latter case few nanosecond...
Article
Full-text available
This paper is a contribution to the study of optical smoothing for application to inertial confinement fusion. Some of the optical smoothing techniques involve intensity space--time modulations in the amplifiers. Because the amplification is planned to produce high power, we cannot neglect the nonlinear effects. We consider here that the space--tim...
Article
The presence of excited state absorption at the 1.06 μm lasing wavelength of Nd doped glasses is demonstrated. The excited state absorption cross-section for silicate (LG680) and phosphate (LG760) glasses was extracted from gains measurements associated to a theoretical model which is described in this paper. From both measurements and the Judd–Ofe...
Article
We study nonlinear effects in amplification of partially coherent pulses in a high power laser chain. We compare statistical models with experimental results for temporal and spatial effects. First we show the interplay between self-phase modulation which broadens spectrum bandwidth and gain narrowing which reduces output spectrum. Theoretical resu...
Article
High energy intense lasers are difficult to focus close the diffraction limit because of phase-front aberrations induced in the optics and amplifiers. This may be an issue in applications where the pulses need to be focused near the diffraction limit such as in ultra-intense femtosecond laser-matter interactions. We describe here a new technique th...
Article
We have implemented a Ti:sapphire/mixed Nd:glass laser syste at LULI producing sub-picosecond pulses in the 100 TW power range. Focusing to a 1.5-times diffraction-limited spot results in a peak intensity on target over 1019 W/cm2. Significant experiments in particle acceleration, X-ray laser and other basic plasma physics researchers have been car...
Article
Full-text available
We develop a statistical model that describes the motion of a hot spot created by smoothing techniques. We define clearly the transverse and longitudinal instantaneous velocities of a hot spot and quantify its lifetime. This relevant parameter is found to be longer than the laser coherence time defined as the inverse of the spec- trum bandwidth. We...
Article
Full-text available
This paper is concerned with the statistical distribution of the maximal hot spots of speckle patterns such as those generated by optical smoothing methods designed for inertial confinement fusion. It is proved that the maximal intensity at the first order is proportional to the logarithm of the ratio of the pulse volume over the mean hot spot volu...
Article
The gain modeling of Nd:phosphate laser glass amplifier devices is investigated both when pumping with laser and flash lamps. Models based upon rate equations are developed, which include either spectroscopic loss mechanisms that may exist in Nd-phosphate glass or realistic pumping geometry. Results showed that the energy transfer up-conversion con...
Conference Paper
Summary form only given. High efficiency of the Transient Collisional Excitation (TCE) pumping of X-ray lasers has been demonstrated recently. TCE relies on the rapid increase of the electron temperature in a preformed plasma irradiated with a short picosecond pulse. This plasma is created by a subnanosecond pulse and contains a predominant proport...
Conference Paper
Summary form only given. Ultra intense laser systems with peak power in the 10 TW-1 PW range are difficult to focus close to the diffraction limit because of spatial phase aberrations. Reaching this goal is an important task when trying to get the highest possible intensity (typically >10<sup>20</sup> w/cm<sup>2</sup>). In this paper, we describe a...
Article
Full-text available
LULI will play an important role as a major laser ICF and IFE support facility in Europe after recent or future changes (ASTERIX-Garching, CEA-Limeil) in large laser system programs. We will review the research activities which have been carried out at LULI during the last 2 years both in the nanosecond regime and in the subpicosecond ultrain...
Article
We demonstrate efficient frequency tripling of 1057-chirped pulses, using adapted chirping and thick KDP crystals. These millijoules broadband pulses at 352 nm have been compressed to 220-fs duration by use of a UV grating-pair compressor. The technique is scalable to kilojoule petatwatt lasers.
Article
The authors report on the intensity and polarisation dependences of electron energy spectra from multiphoton ionisation of xenon with 120 fs pulses at 615 nm. The spectra show a large number of narrow structures assigned to resonances induced by the AC Stark shift. The structures are suppressed with circular polarisation. The maximum shift is obser...
Article
Xenon was ionised by 100 fs UV pulses. The electron spectra showed a decreasing energy of the photoelectrons with increasing light intensity. No resonances were observed in the electron spectrum. The absence of resonances is understood in terms of the ratio of the pulse duration and the characteristic time (2 pi n3 in au) of the intermediate state....
Article
Full-text available
Electron energy spectra from multiphoton ionization of krypton with 617 nm, 70 fs pulses have been recorded over a large intensity range. Near the appearance intensity, the spectra display Stark-induced resonances with s and d states. Up to about 8*1013 W cm-2, the spectra broaden and the structures are progressively washed out. Above this intensit...
Article
Summary form only given. The generation of ultrashort pulses has been progressing in the recent years with outstanding advances in the shortening of pulses and the increase of their spectral regions of emission. The experiments were performed using a Ti:sapphire femtosecond laser and a CPA amplifier configuration based on a Ti:sapphire regenerative...
Article
We describe the principle of the polychromatic laser guide star (LGS) to recover the tilt information in imaging through the atmosphere. Observations using the AVLIS laser at the Lawrence Livermore National Lab are discussed in terms of returned flux in the ultraviolet. The major items of the program ELP-OA, starting now in France, are briefly revi...
Article
We demonstrate efficient generation of picosecond narrow-bandwidth pulses by frequency mixing of broadband opposite chirped pulses in a type I doubling crystal. This procedure allows us to produce picosecond pulses that are perfectly synchronized with femtosecond pulses. The experiment shows a decrease of the initial bandwidth by a factor of more t...
Conference Paper
Ultra-intense laser systems with peak power in the 10 TW-1 PW range are difficult to focus close to the diffraction limit because of phase-front aberrations. In this paper, we describe a new technique we have implemented, which significantly improves the focal spot quality by correcting the wave front from a highly distorted laser beam. In this exp...
Article
Space aberration effects which arise in high energy or in high average power laser chains are important parameters to control in order to emit a beam quality close to the diffraction limit. For that purpose we present recent experiments using an original adaptive and programmable module allowing the spatial control of the beam amplitude and the cor...
Article
We demonstrate correction of laser wave-front distortions by use of an adaptive-optical technique based on a light valve. The setup consists of an achromatic and adjustable-sensitivity wave-front sensor and a wave-front corrector relying on an optically addressed liquid-crystal spatial light modulator. Experimental results with strongly aberrated b...
Article
We show the presence of the excited state absorption (ESA) at 1.06 μm in the Nd-doped glasses and we quantify the ESA cross section for silicate (LG680) and phosphate (LG760) glasses. During the pumping, the upconversion process and the ESA at the pump wavelength populate the 4G excited states
Article
We report an experimental verification of a previously published concept, which allows us to efficiently frequency-triple broadband pulses using a chirped-pulse amplification (CPA) configuration. The idea is based on the manipulation of pulses with appropriate chirps for maintaining phase matching over the whole bandwidth. It either starts from two...
Article
We demonstrate the efficient generation of synchronized monochromatic pulses in the 5- to 10-ps range, using a femtosecond chirped amplification system. The method relies on the control of the pulse frequency time sweep introduced in a CPA system using the property of symmetry in a type I sum-frequency crystal. We use the output of a chirped amplif...
Conference Paper
Full-text available
This paper is concerned with the statistical comparison of 2D smoothing by spectral dispersion and smoothing by optical fiber, both techniques being proposed for uniform irradiation in plasma physics. In the asymptotic framework of a large number of elements of the random phase plate or excited optical modes of the fiber, closed-form expressions fo...
Article
Full-text available
We have developed a statistical nonlinear model to explain an anomalous intensity saturation observed in the amplification of intense broadband incoherent pulses on neodynium-doped glass power chains. The physics behind this model is basically self-phase modulation creating new wavelengths scattered in the tail of the gain profile. The theory shows...
Article
Full-text available
We develop statistical tools for beam smoothing analysis. As applications we study the respective performances of two-dimensional smoothing by spectral dispersion and of smoothing by optical fiber. The calculations are valid in the asymptotic framework of a large number of elements of the random-phase plate and of excited optical modes of the fiber...
Article
An alexandrite laser is used to longitudinally end-pump mixed Nd:glass rods in a multipass arrangement in order to amplify chirped pulses in the 50-100-mJ range at a 1-Hz repetition rate. This system has a broad-band capability of up to 8-10 nm output bandwidth. We have developed a model, which in our specific case of amplification of chirped-pulse...
Conference Paper
Summary form only given. Here, we develop a time analog of optical adaptive methods in the context of the chirped pulse amplification (CPA) technique, with the goal of finely tuning the phase using pure electronic means in order to compress at best the amplified pulses. CPA systems are not perfect in that the pulses acquire high-order phase terms i...
Article
Full-text available
We excite quantum beats in a quantum well using 12 fs optical pulses. The resulting coherent charge oscillation, in the tens-of-tetrahertz range, radiates a corresponding infrared electromagnetic wave which is monitored through heterodyne detection using as a reference a nearly single-cycle infrared pulse. The direct observation of this wave-packet...
Article
Full-text available
We have developed a new scheme of Fourier-transform spectroscopy in the mid and the far infrared. The method relies on an interferometer in the visible or the near infrared, providing a sequence of two femtosecond pulses, which in turn generate a sequence of infrared pulses. The geometrical properties of the different diffracted infrared waves are...