Research News

A laser-plasma tool to reduce the drag experienced by a supersonic object

Edited: November 9th, 2018

When a body moves in the atmosphere with a supersonic velocity, a shock wave is generated. This leads to a considerable increase in the drag experienced by the supersonic object towing the shock wave. This shock wave increases fuel consumption and produces a sonic boom that renders regular supersonic flight above populated area unacceptable. Through a collaboration with the French aerospace Lab ONERA and with Phasic company, researchers from LOA recently demonstrated that an embarked terawatt femtosecond laser can significantly decrease this drag. A 50% transient reduction of drag has been measured on a test model placed in a supersonic wind tunnel at Mach 3. This effect was initiated by the thin hot air column created in front of the supersonic object by filamentation of the laser pulse. This technique also offers possible means of weightless steering.

 

Reference: « Improving supersonic flights with femtosecond laser filamentation », P.-Q. Elias, N. Severac, J.-M. Luyssen, Y.-B. André, I. Doudet, B. Wattellier, J.-P. Tobeli, S. Albert, B. Mahieu, R. Bur, A. Mysyrowicz and A. Houard, Science Advances 4, eaau5239 (november 2018)

Research news Ecole Polytechnique

 


G. Mourou, LOA Director 2005-2008 awarded Nobel prize of Physics 2018

Edited: 2018 october

Gérard Mourou is the co-inventor, joint work with Donna Strickland, of the Chirped Pulse Amplification (CPA) technique (thirty years ago). This technique rendered possible the amplification of short laser pulses (a few dozen femtoseconds; 1fs = 10^(-15) s) up to extremely high peak powers, equal to a petawatt (1PW = 10^(15)W) or even more. The principle: temporarily spread an ultra-short pulse by means of an optical network in order to reduce its actual intensity before magnifying it. The pulse is then recompressed to reach intensities a conventional amplification would not make it possible to reach.
The CPA technique revolutionized the field of laser science and found new applications in different branches of Physics like in laser-produced plasma research.
After the start of his carreer at LOA in the late seventies, Gérard Mourou spent a large part of his career in the United States, in particular at the University of Rochester and Michigan. Back in France and in LOA in 2005, he was in charge of the lab until 2008. During this time, he initiated at LOA the research program on high repetition rate and intense laser systems with pulse durations of few optical cycles. With the LOA team, he also launched the PW Apollon laser program, now located in the Saclay plateau as well as the Large European infrastructure ELI (Extreme Light Infrastructure ), the world’s largest ultrafast lasers, that will be hosted  in Hungary, Romania, and Czech Republic.


Stable femtosecond X-rays

Edited: 2017/11/28

Technology based on high peak power lasers has the potential to provide compact and intense radiation sources for a wide range of innovative applications. In particular, electrons accelerated in the wakefield of an intense laser pulse will oscillate around the propagation axis and emit X-rays. This betatron source, which essentially reproduces the principle of synchrotron on a millimeter scale, provides bright radiation with femtosecond duration and high spatial coherence. But despite its unique features, the usability of the source has been constrained by its poor control and stability. In this letter, we demonstrate reliable production of X-ray beams with tunable polarization. Using ionization-induced injection in a gas mixture, the orbits of the relativistic electrons emitting the radiation are reproducible and controlled. We observe that both signal and beam profile fluctuations are significantly reduced, and the beam pointing varies less than a tenth of the beam divergence. The polarization ratio reaches up to 80 percent and the polarization axis can be easily rotated. We anticipate a broad impact of the source as its unprecedented performance opens the way to new applications.

These results have been published in LIGHT, november 2017

Caption: Betatron radiation beam profiles in the classical (transverse injection) and recently studied (ionization injection) regimes.

 


High rep rate laser-plasma accelerators

Edited: 2017/04/11

– April 10th, 2017 – laser-plasma accelerators demonstrated with high repetition rate and compact laser systems (Nature Photonics)

Laser–plasma acceleration is an emerging technique for accelerating electrons to high energies over very short distances. The accelerated electron bunches have femtosecond duration, making them particularly relevant for applications such as ultrafast imaging or femtosecond X-ray generation. Current laser–plasma accelerators deliver 100 MeV to GeV electrons using Joule-class laser systems that are relatively large in scale and have low repetition rates, with a few shots per second at best. Nevertheless, extending laser–plasma acceleration to higher repetition rates would be extremely useful for applications requiring lower electron energy. Here, we use single-cycle laser pulses to drive high-quality MeV relativistic electron beams, thereby enabling kHz operation and dramatic downsizing of the laser system. Numerical simulations indicate that the electron bunches are only ∼1 fs long. We anticipate that the advent of these kHz femtosecond relativistic electron sources will pave the way to applications with wide impact, such as ultrafast electron diffraction in materials with an unprecedented sub-10 fs resolution.

« Relativistic electron beams driven by kHz single-cycle light pulses »
D. Guénot, D. Gustas, A. Vernier, B. Beaurepaire, F. Böhle, M. Bocoum, M. Lozano, A. Jullien, R. Lopez-Martens, A. Lifschitz and J. Faure*

Nature Photonics (2017)

doi:10.1038/nphoton.2017.46, Published online 10 April 2017

https://www.polytechnique.edu/fr/content/lacceleration-laser-plasma-pour-explorer-la-matiere

Attached document ]

 


FET-OPEN awarded to LOA

Edited: 2016/11/04

– November 4th, 2016 –  An European FET-OPEN program of 3,9 M€, Laser Lightning Rod (LLR), has been awarded to a consortium leaded by Aurelien HOUARD at LOA.

Controlling lightning is a long time dream of mankind. The goal of the present project is to investigate and develop a new type of lightning protection based on the use of upward lightning discharges initiated through a high repetition rate multi terawatt laser. The feasibility of the novel technique and the project’s prospect of success are based on recent research providing new insights into the mechanism responsible for the guiding of electrical discharges by laser filaments, on cutting-edge high power laser technology and on the availability of the uniquely suitable Säntis lightning measurement station in Northeastern Switzerland (2500 m).

The LLR consortium is ideally positioned to succeed and to raise the competitiveness of Europe in lightning control as it relies on the integration of trans-disciplinary fields in laser development, nonlinear optics, plasma physics, remote sensing, and lightning: The project team is made up of leaders in the domains of high power nonlinear propagation of laser pulses in the atmosphere, laser control of electric discharges, lightning physics, high power laser development, and high-repetition-rate lasers. In addition, the largest European company in aeronautics brings its expertise in lightning direct effects and protection means on aircraft and infrastructures.

This is the second FET-OPEN contract awarded to LOA.

4% over the 522 eligible projects have been awarded.

The consortium: LOA (coordinator), EPFL, Université de Genève, Trumpf, Airbus GI, HESSO

More information: http://llr-fet.eu

 


ERC starting awarded at LOA

Edited: 2016/09/07

– September 1st, 2016 – An ERC starting grant has been awarded to a researcher at LOA, Sebastien Corde, on the development of a novel plasma particle acceleration technology .

As we push the frontier of particle physics to higher particle energies, conventional accelerator techniques are attaining their limits and new concepts are emerging. The use of an ionized gas —or plasma— circumvents the most significant barrier of conventional techniques by increasing the energy gained per unit length by several orders of magnitude. One class of plasma accelerators, relevant for high energy physics applications, consists in using a particle beam, « the driver », to excite a plasma wave, that is then used to accelerate the main particle beam. Research in this field requires large facilities, due to stringent conditions on the driver. In the M-PAC project (Miniature beam-driven Plasma ACcelerators), I propose to power plasma accelerators with laser-accelerated electron beams based on 100-TW-class laser systems, so as to miniaturize the so-called “beam-driven plasma accelerators”. The project crosses the boundary of the fields of research of laser acceleration and of beam- driven plasma acceleration. With these innovative miniature versions, the goal of the M-PAC project is then to tackle, through experiments and simulations, the next Grand Challenges facing the field of beam-driven plasma acceleration, bringing plasma accelerator technology to viability for high energy physics collider applications. They include the generation and preservation of the excellent beam quality required for high- energy colliders and next-generation light sources, the demonstration of high drive-to-main-beam energy efficiency and the acceleration of the antimatter counterpart of the electron, the positron. Finally, the miniature beam-driven plasma accelerators open new opportunities to push university-scale plasma-based light sources to the next level, both in terms of brightness and spectral range.

This is the ERC number 6 awarded to LOA researchers since the launch of the program in 2009.

 


Plasma accelerators driven by particle beams

Edited: 2016/06/24

– June 23rd,  2016 – An international team involving a scientist from LOA has published two studies in the journal Nature Communications, improving the capabilities and the understanding of plasma accelerators driven by particle beams.

In the first study [Nat. Commun. 7, 11785 (2016)], the researchers were able to create a new type of plasma accelerator, taking the form of a hollow plasma channel – a tube of plasma with neutral gas on the inside. With this particular geometry, particles flying in the tube won’t experience transverse forces that can be detrimental to the quality of the beam. This is critical for the positron, the antimatter sibling of the electron, whose acceleration in plasma is extremely challenging. By sending a beam of positrons into the tube, the authors were able to excite a wakefield that can be used for the acceleration of positrons, and that is free of unwanted transverse forces.

In the second study [Nat. Commun. 7, 11898 (2016)] lead by Sebastien Corde from LOA, the scientists have investigated the dynamics and interaction of an electron beam with self-produced plasma. In this case, the plasma is directly generated by the ionization of a gas by the electron beam itself. When the beam travels through a high-ionization-potential gas (such as argon), as in the reported experiment, the conditions are expected to be strongly unfavorable for plasma acceleration and very small gain of energy (sub-GeV) was anticipated. Instead, surprisingly large energy gains, up to 27 GeV, were experimentally observed, in disagreement with expectations.
The results have revealed two key phenomenons that are taking place and make this very high-field acceleration possible. First, the beam undergoes self-focusing: its beam size is rapidly reduced and then maintained at its minimum value so that the beam becomes very dense and can drive high-field plasma wakes (see figure). Second, such a beam does not undergo continuous head erosion, because the particles at the head of the bunch have very low divergence and they provide an onset of ionization sufficient to provide guidance for the rest of the beam.
These unexpected and surprising results provide a more complete understanding of the interaction between beams and plasmas, which will certainly guide future optimizations of beam-driven plasma accelerators.

Articles:
S. Gessner et al., Nat. Commun. 7, 11785 (2016) – http://dx.doi.org/10.1038/ncomms11785
S. Corde et al., Nat. Commun. 7, 11898 (2016) – http://dx.doi.org/10.1038/ncomms11898


2016 E. Fabre prize awaeded to J. Faure

Edited: 2016/04/28

The prize “Edouard Fabre 2016” for contributions to the physics of laser-driven inertial confinement fusion and laser-produced plasmas has been assigned to Jerome Faure, LOA. The Prize is especially addressed to researchers in full activity, within about 15 years after obtaining their Ph.D.

In 2003, J. Faure obtained a CNRS position at Laboratoire d’Optique Appliquée where he performed remarkable experimental work in developing laser-plasma accelerators, demonstrating the possibility of using laser-plasma interaction to accelerate electrons in extremely short distances and producing high quality electron beam. In 2012, he got an ERC Starting grant to produce with a kHz laser system, femtosecond electron bunches and to apply them for the study of ultra fast phenomena using electron diffraction with femtosecond time resolution. In parallel Jerome Faure teaches quantum physics and statistical physics as Associated Professor at Ecole Polytechnique. He is now a CNRS research director and the head of the APPLI research group at LOA (Application of ultrafast sources to solid state physics).

more information here

 


First ENSTA-ParisTech MOOC

Edited: 2016/02/09

– February 9th, 2016 – The first MOOC of ENSTA-ParisTech was posted on February 4, 2016 in FUN, the French e-learning platform. Davide Boschetto, researcher at LOA laboratory, offers a first course on the Introduction to Quantum Physics. 5 days following its launch, more than 600 e-students have already registered. The course will start April 25th, 2016. FUN includes more than 50 partners in France and around the world, among with ENSTA-ParisTech.

more information:

MOOC Physique Quantique

Teaser (dailymotion)

 


Vacuum laser acceleration of relativistic electron

Edited: 2016/01/14

– December 21st, 2015 – Two teams from CEA LIDYL and Laboratory for Applied Optics (LOA) at ENSTA-ParisTech – Ecole Polytechnique – CNRS were able to demonstrate for the first time the vacuum acceleration of electrons to relativistic energies by an intense laser beam. These results are published in Nature Physics (december 2015). This observation shows that it is possible to take benefit of the very strong amplitudes of the electric field of femtosecond laser pulses that are used today to accelerate high-energy particles over short distances.

By concentrating the light over periods of femtoseconds (10-15 s) durations, the laser pulses can reach very high instantaneous light powers (~ 1 PW or 1015 W) and hence extremely high amplitudes of the associated electric field (~ 10 TéraV/m or 1013 V/m).

Like the large sea waves off the coast that can not move ships, this oscillating field can not accelerate at very high energy charged particles. But like the surfer who is at first providing speed on its own to catch the wave and then continuously enjoy its slope, the injection of relativistic electrons  in the laser beam  (with a speed very close to that of light) can theoretically enable its acceleration, taking the full advantage of extremely high electric fields associated with the ultrashort laser pulse.

Many teams around the world have tried to demonstrate this phenomenon, without being able to provide convincing proof up to now. LOA and LYDIL researchers show that the interaction of the laser pulse with a solid target (plasma mirror) provides the ideal electron injection conditions. Electrons have been accelerated to about 10 MeV energies over a distance of 80 micrometers. This experiment paves the way to realize ultra-compact electron accelerators of very high energies.

Caption: Electron beam profile from the plasma mirror. The colors reflect the number of electrons emitted in a given direction. Deflected due to the acceleration of 1.5 MeV to 10 MeV over a distance of 80 microns by the laser pulse, the high energy electron beam is visible at the center of the figure (red spot), while very few electrons are emitted in the direction of the reflected light beam (white spot). © F. Quéré (CEA) – J. Faure (CNRS).

ArticleM. Thevenet, A. Leblanc, S. Kahaly, H. Vincenti, A. Vernier, F. Quéré and J. Faure, Nature Physics (2015)

CNRS press release

CEA press release

 


Fluctuations of atomic positions captured

Edited: 2016/01/14

– December 22, 2015 – Two teams from LOA and the Triestre Research Center in Italy have been able to catch the fluctuation of atomic positions. The results are published in the journal Nature Communications.

The time evolution of atomic positions in materials is usually addressed by means of non-equilibrium optical spectroscopy. An ultrashort light pulse (the pump) impulsively perturbs the lattice and a second one (the probe), properly delayed in time, measures a response that is proportional to the spatially averaged instantaneous atomic positions. In those experiments, the time-dependent atomic displacements are often revealed by an oscillating response, commonly dubbed coherent phonon response, at frequencies characteristic of the vibrational modes of the material. In this framework, it has been shown that a non-linear light–matter interaction can prepare non-classical vibrational states such as squeezed states, where the fluctuations of the lattice position (or momentum) can fall below the thermal limit. A joint experimental and theoretical approach have been done to access the fluctuations of the atomic positions in time domain studies.

Article: Photon number statistics uncover the fluctuations in non-equilibrium lattice dynamics, Martina Esposito, Kelvin Titimbo, Klaus Zimmermann, Francesca Giusti, Francesco Randi, Davide Boschetto, Fulvio Parmigiani, Roberto Floreanini, Fabio Benatti & Daniele Fausti, Nature Communications 6, 10249 (2015)


Femtosecond x-ray laser

Edited: 2015/11/17

– November 16th, 2015 – For over a decade, the duration of flashes of XUV laser radiation generated from laser-plasma interaction was limited to a few picoseconds, reducing access to many pioneering and innovative applications in the ultrafast range. A team of the Laboratory of Applied Optics (LOA) led by Stéphane Sebban has just published in the journal Nature Photonics results demonstrating, for the first time, that intense femtosecond pulse duration can be obtained. The amplifying medium is a plasma of nickelloïd krypton emitting at 32.8 nm which was injected by a source of high-order harmonics obtained in argon. Laboratory-size applications previously limited to large infrastructures such as synchrotrons or free electron lasers become feasible. This work was carried out in cooperation with the LPGP (University Orsay), the ELI-Beamlines Project (Prague), the APRI Laboratory (Gwangju, South Korea) and LULI (Ecole Polytechnique, Palaiseau).

More information :

– Article : Table-top femtosecond soft X-ray laser by collisional ionization gating, A. Depresseux et al., Nature Photonics, Published online 16 November 2015

– Press release

 


Accélération d’antimatière

Edited: 2015/08/27

– Nature, S. Corde et al, august 27th, 2015 – For several years, plasma accelerators have shown their tremendous ability to accelerate particle beams. One objective is to downsize the experimental facilities and to allow the generation of very high energies while keeping the infrastructures within achievable size. To date, plasmas created by laser based on the interaction of an intense femtosecond laser with the matter or plasmas created by electron beams generated from RF accelerators, have accelerated energetic electrons with remarkable properties like ultrafast pulse duration, charge, energy or compactness in the case of lasers.

Sébastien Corde, researcher at LOA, has this time shown (Nature on August 27, 2015) with an international team working on the SLAC-FACET infrastructure at Stanford (USA), how these plasmas can be used to accelerate an other type of particles, the positrons. A positron beam with an initial energy of 20 GeV could gain 5 GeV by capturing about 30% of the energy of the plasma. These results are an important step toward the realisation of the next generation of particle colliders.

– Illustration: Weiming An (UCLA)

– More information:

communiqué de presse

S. Corde et al, Nature 524, 442–445 (27 August 2015)

News and views Nature

 


Circularly Polarized Plasma x-ray laser

Edited: 2015/08/28

– August 19th, 2015 – The team led by S. Sebban at LOA has shown that x-ray laser beams generated from laser-based plasmas can now provide circular polarization features. Added to its very short time pulse duration, this result opens the door to numerous imaging applications in nanomaterials and biology with compact instruments. X-ray magnetic circular dichroism (XMCD), the difference in absorption for left- and right-circularly polarized X-rays by a magnetized sample, constitutes nowadays an outstanding tool for the study of magnetism. Many biological molecules absorb right- and left-handed circularly polarized light differently depending on their structure, so polarized light sources can be used to probe the shapes of molecules. In particular, coherent “soft” x rays, which have wavelengths of up to a few tens of nanometers, are useful for imaging live cellular material.

These results are highlighted by the APS Physics Society and the journal Nature Photonics.

More information:

A. Depresseux et al, Phys. Rev. Lett. 115, 083901 (2015)

APS Physics highlight

Nature Photonics highlight

 


laser-plasma accelerators at LOA

Edited: 2015/07/23

Victor Malka, CNRS Research Director at LOA (Laboratoire d’Optique Appliquée – École polytechnique, ENSTA Paris-Tech, CNRS)  presents in this « Labshot » his work on the laser-plasma accelerators.
Laser-plasma accelerators have potential applications in radiotherapy, in medical imaging and in materials’ science.

Watch the video here

 


LOA Nature Physics on plasma magnetization

Edited: 2015/04/22

– April 22, 2015 – Due to the unique conditions they are able to create, intense lasers are
routinely used to perform studies of fundamental plasma physics and to
reproduce scaled versions of astrophysical plasmas.

Researchers from the LOA in strict collaboration with researchers from
the IST in Lisbon have been able to observe a new mechanism of plasma
magnetization, occurring when heated plasma electrons cross the boundary
between ionized and neutral gas.

The experiment, realised in the Salle Jaune, enabled the researchers to
follow at high spatial and temporal resolution the birth and the growth
of strong magnetic fields in a dense, ionized, Helium gas jet. These
results open the possibility to model on the laboratory scale the
generation of giant magnetic fields observed in astrophysical plasmas.

These results have been published as advance online publication in
Nature Physics (http://dx.doi.org/10.1038/nphys3303)

 


Medical X-ray imaging at LOA

Edited: 2015/03/06

A European FET OPEN program on medical x-ray imaging has been awarded to LOA early in March 2015. The project, called VOXEL (Volumetric medical X-ray imaging at extremely low dose) is part of the European framework programme Horizon 2020 on Research and Innovation actions for Future and Emerging Technologies. Coordinated by IST (Portugal), the project gathers research teams from France (LOA, Imagine Optic, LIDyL), Netherland (CWI), Italy (CNR) and Spain (UPM).

Abstract of the project:

Computerized Tomography (CT) has been one of the greatest achievements in medical imaging, but at the cost of a high, potentially harmful, X-ray irradiation dose. The ultimate goal of VOXEL is to provide an alternative to tomography with a disruptive technology enabling 3D X-ray imaging at very low dose. VOXEL aims at prototyping new cameras working in the soft and hard X-rays (< 10 keV) that will combine the X-ray penetration and nanometre spatial resolution, easiness to use, afforded by avoiding the rotation of the source or the sample, and extremely low dose for maximum impact on medicine and biology.

VOXEL relies on the integration of trans-disciplinary fields in medical imaging, optics, X-ray physics, applied mathematics and value to society through foreseeable commercialization. VOXEL aims at prototyping in parallel a soft X-ray “water window” microscope and a hard X-ray 3D camera for medical applications (< 10 keV). While both cameras need groundbreaking development in the underlying physics, only hard X-ray camera has high technological risk (and high societal impact). VOXEL will benefit from the soft X-ray camera thanks to its Biological applications in nano-tomography but also as a test platform for our physical and mathematical models.

The VOXEL team members are leaders in X-ray metrology, wavefront sensing, atomic physic, mathematical computing and 3D medical imaging; with VOXEL we are uniquely positioned to succeed, and to raise the competitiveness of Europe. Doing so by basing the research lead in Portugal with a woman coordinator will be exemplary: beyond the scientific and technological success, thanks to our focus in science and its valorisation, VOXEL will be transformative for scientifically emerging countries.

 


Nature Com. publication: plasma lens

Edited: 2015/03/20

– March 6th, 2015 – Many applications of laser-plasma accelerators, notably compact free-electron lasers and multi-stage colliders, require the electron beam to be transported. Yet, to date, no existing device can properly focus the electron bunch produced by a laser-wakefield accelerator (conserving its emittance), mainly due to its few milli-radian divergence.
Researchers from LOA showed that this critical issue can be solved thanks to a new concept, the laser-plasma lens. This laser-plasma lens, which consists of a second gaz jet placed a few millimeters after the accelerator, was used to collimate the beam and reduce its divergence by nearly a factor of 3. The critical parameter, for efficient beam transport being the square of the divergence, the demonstrated divergence reduction leads to a gain of almost one order of magnitude, which should be sufficient to open the way to applications. Experiments have been done using the Salle Jaune Facilty at LOA.

http://www.cnrs.fr/inp/spip.php?article3787

 


Intense elliptically-polarized harmonic source

 Edited: 2015/02/10

– February 4th, 2015 – Using the femtosecond kHz laser called Salle Orange at LOA, we have developed and studied an novel harmonic source which is intense and provides highly elliptical polarization. This source is quasi unique in the world, and has enabled us to realize with succes a magnetic dichroism experiment on a nickel sample at 18 nm (67 eV). The collaboration gathers few reaserch teams at LOA and colleagues from the laboratory LCPMR (University of Jussieu Paris VI). So far this type of experiment could only done at large installations like synchrotron and free electron laser. Now, with our compact laboratory-size harmonic source, we plan to achieve such experiments even with unbeatable temporal resolutions (a few fs). These results were published in early February 2015 in the Nature Communications (Nature Communications 6, 6167 (2015).

 


New ERC Proof of Concept grant at LOA

Edited: 2015/01/22

January 22th, 2015 – An ERC grant Proof of Concept (POC) has been awarded to LOA (V. Malka) on the development of innovative technologies for cancer detection at an early stage. The project includes the scientific developments of several LOA researchers like K. Ta Phuoc, C. Thaury and S. Corde. The most advanced electron beams produced by laser plasma accelerators will be used to radiate a bright, tunable X ray beam to significantly improve the spatial resolution of the imaging technique of low contrast biological objects.

ERC POC grants support high-risk/high-gain research at the frontiers of knowledge to generate unexpected or new opportunities for commercial and societal applications. It helps ERC grant-holders (Advanced grant in this case) to bridge the gap between research and the earliest stage of a marketable innovation.

This is the fifth ERC grant awaded to LOA researchers.

 


E. Fabre prize for LOA

Edited: 2014/09/15

Stéphane Sebban, CNRS researcher at LOA, won the E. Fabre international award for his pioneering work on X-ray laser developments using intense femtosecond lasers and plasmas. The prize was delivered at the 17th International Congress on Plasma Physics (ICPP 2014) held in Lisbon, Portugal, and is awarded to experienced international researchers having a research activity of less than 15 years after their PhD.

 


First energetic protons at SAPHIR

Edited: 2014/03/27

First energetic protons at SAPHIR –

SAPHIR project aims at determining the technical and economical viability of laser protons therapy, as an alternative to the classical particle acceleration technics for curing cancer. The final goal of this project is to realize a compact and affordable system to be installed directly in hospitals, thus spreading the use of this treatment.

5 laboratories and French institutions (LOA , CPO / Institut Curie , Institut Gustave Roussy , CEA DAM / LIRM IRAMIS and CEA Saclay ) and 4 industrial partners (Amplitude Technologies, Dosisoft , Imagine Optic and Propulse SAS) are involved in SAPHIR. This interdisciplinary project connects physics, biology , oncology, and is largely devoted to technology transfer from basic research to industry.

The experimental system is installed on the site of the LOA at Palaiseau. It has recently been commissioned and the first energetic protons were produced to validate the experimental setup. 5 MeV protons have been generated with a laser energy of about 3J on target and a pulse length of 40 fs. The upgrade of the laser power will allow to study the parameters for efficient production of protons of several hundred MeVs.

Image Caption : Thomson parabola data showing accelerated protons from a solid target
( 6 microns thick) and four traces of carbon ions ( C +, C4 + ) .

 


ERC Senior Grant awarded at LOA

Edited: 2013/07/23

Victor Malka, head of the research group SPL at LOA has been awarded the prestigious 2013 European ERC grant. The objective of the so called X-5 project is to demonstrate the feasibility of the 5th generation of high energy radiation sources, which are expected to be compact, to lower the costs, and to meet the growing demand of the scientific community. These novel sources will be produced using laser-based high-energy electron accelerators coupled to magnetic permanent magnet undulators or plasma wigglers. The project includes a strong collaboration with teams from the Synchrotron SOLEIL. This is the 4th ERC grant awarded to LOA teams.

ERC Advanced Grants allow exceptional established research leaders of any nationality and any age to pursue ground-breaking, high-risk projects that open new directions in their respective research fields or other domains.
The ERC Advanced Grant funding targets researchers who have already established themselves as independent research leaders in their own right.

 


The upgraded Salle Jaune Laser shines again

Edited: 2013/06/18

After 1 year and a half break and an intense work of the technical support and researchers teams to carry out a huge upgrade program, the LOA laser Facility « Salle Jaune » and the related experimental sites have just done their first shots on target.

First experiments of laser-matter interaction have been performed successfully on the acceleration of energetic electrons (image: 3 electron spectra around 400 MeV from 3 consecutive laser shots) and the generation of ultrashort X-rays. It is remarkable that these first results were obtained only a few minutes after re-focusing the laser on target for the first time since the stop of the facility 18 months ago, indicating a very high quality of the laser beam properties and of the interaction parameters.

The laser now delivers a power of 120 TW on target splitted on multiple beams. Three fully equiped experimental sites are now available to perform complex plasma physics experiments thanks to the multiple beams spatially and temporally synchronized.

This project was funded by ENSTA, Ecole Polytechnique, CNRS and numerous contracts including a ERC European project and few ANR programs from the french Ministery of Research.

 


Rainbow pattern from laser-plasmas

Edited: 2013/03/13

Intense light pulses that can precisely sculpt solid materials also generate dazzling rainbow patterns that reveal information about the surface.

Not just a pretty face. This colorful pattern of light scattered from a solid surface being hit with laser pulses can convey details of the surface damage, such as the size of the laser-generated crater.

A spectacular sunburst of colored light produced as a laser beam bores into a solid surface could reveal information about the damage the light causes, according to a report in Physical Review Letters. The authors observed the rainbow pattern as they blasted a series of transparent materials such as glass and quartz with intense laser pulses. The team says that this effect, surprisingly overlooked until now, could offer a way of monitoring laser ablation, a technique used in fields as varied as dental surgery and art preservation.

Reference:

– American Physical Society – Physics

– Ciliary White Light: Optical Aspect of Ultrashort Laser Ablation on Transparent Dielectrics
Yi Liu, Yohann Brelet, Zhanbing He, Linwei Yu, Sergey Mitryukovskiy, Aurélien Houard, Benjamin Forestier, Arnaud Couairon, and André Mysyrowicz
Phys. Rev. Lett. 110, 097601 (2013)

 


Improved stability of laser-plasma electron beam

Edited: 2013/02/07

Laser-plasma accelerators can produce high quality electron beams, up to giga-electronvolts in energy, from a centimeter scale device. The properties of the electron beams and the accelerator stability are largely determined by the injection stage of electrons into the ac- celerator. The simplest mechanism of injection is self-injection, in which the wakefield is strong enough to trap cold plasma electrons into the laser wake. The main drawback of this method is its lack of shot-to-shot stability. Researchers from LOA have demonstrated the existence of two different self-injection mechanisms. Transverse self-injection is shown to lead to low stability and poor quality electron beams, because of a strong dependence on the intensity profile of the laser pulse. In contrast, longitudinal in- jection, which is unambiguously observed for the first time, is shown to lead to much more stable acceleration and higher quality electron beams. These results are published in Nature Communications, February 19th, 2013.

 


Attosecond lighthouse

Edited: 2012/12/18

Nature Photonics, December 2012 – The dynamics of electrons in atoms and molecules is extremely fast (order of magnitude: attosecond, or 10-18 s). One way to study these phenomena is to use pulses of ultra-short light on these timescales. With the demonstration carried out at the Laboratory of Applied Optics (LOA, CNRS / ENSTA-ParisTech / Polytechnique) by researchers from LOA and  CEA-IRAMIS, it is possible to have today unique light sources. From a single laser pulse focused onto a plasma, several isolated attosecond pulses can be produced. The beams are well angularly separated and perfectly synchronized. The attosecond « lighthouse » is an ideal light source for future pump-probe experiments to study the ultrafast dynamics of electron in matter.

These results were published in Nature Photonics, 1 December 2012.

Read the news

 


New LaserLab coordinator

Edited: 2012/11/05

Claes-Göran Wahlström from the Lund Laser Centre at Lund University, Sweden, has been elected as the new Coordinator of LASERLAB-EUROPE, the European Laser consortium.  He succeeds Wolfgang Sandner, Max-Born-Institute, Berlin, who lead the consortium and its evolution through several successive Framework Programmes of the EU, starting with the FP5 thematic network LASERNET in 2001. Meanwhile the consortium has grown to 28 partner institutions, comprising, together with subcontractors, 19 European countries. It has just started a new project period, funded by the European Union and ranging from 2012 through 2015.
Claes-Göran Wahlström is Professor of Physics at the Lund University, where he is the head of the Atomic Physics Division, at the Department of Physics, and of the Lund Laser Centre. His own research addresses ultra-high intensity laser matter interactions, and laser-driven particle acceleration in particular. Since 2010 he is an elected member of the Royal Swedish Academy of Sciences.
The hand-over took place during the General Assembly Meeting in Munich on October 25. In his inauguration speech, Claes-Göran Wahlström thanked Wolfgang Sandner for his achievements, having brought together two laser communities, the former “high-energy laser infrastructures” and the “analytical laser facilities”, and having led them to become a powerful network. He also pointed out the options for the further development of the consortium and his commitment to lead LASERLAB-EUROPE into a successful and sustainable future.
The LASERLAB-EUROPE partners congratulate Claes-Göran Wahlström to his election and wish him all the best for the future coordination of the LASERLAB network. They also thanked Wolfgang Sandner who will assume new tasks in the European ESFRI project ELI, the “Extreme Light Infrastructure”, the world’s first international scientific laser project. Claes- Göran Wahlström will be assisted in his new tasks by the Forschungsverbund Berlin e.V., the legal entity holding the LASERLAB grant agreement with the EC, and by the LASERLAB Berlin office, who both will continue in their functions.

LOA belongs to the consortium since its start more than 10 years ago. It plays an active role in the research and access facility  programs as well as in the coordination of the consortium with its recent election at the Management Board.

 


ENSTA-ParisTech moves to Palaiseau

Edited: 2012/10/08

The french National School of Advanced Techniques (ENSTA ParisTech) has just moved this september from Paris to Palaiseau. ENSTA ParisTech was located in Paris since its creation in 1970. In 2012, the school of engineering is moving on the Paris-Saclay Campus, located on the Saclay plateau. The new campus provides teaching facilities, student accommodations, catering and hotel services and a range of outstanding sporting facilities for the people who live, work and study there. Saturday, October 6, 2012, a first event has gathered around 1000 people came to visit the new school in a friendly and musical atmosphere. The official inauguration took place Saturday, October 13, 2012.

 


ERC « starting Grant award at LOA

Edited: 2012/06/25

Jerôme FAURE, a CNRS staff researcher at LOA, has been awarded a junior European ERC starting grant  (June 2012). This highly selective program favors the emergence of the next-generation of research leaders, who bring new ideas, and it encourages highly talented researchers at an early stage of their career to seek advancement. ERC Starting Grants aim to support up-and-coming research leaders who are about to establish or consolidate a proper research team and to start conducting independent research.

Jérôme FAURE will develop innovative femtosecond laser-plasma based electron source at high repetition rates to study the ultrafast structures of the matter. His research program will be done with the latest LOA laser infrastructures.

Attached document ]

 


LOA results highlighted

Edited: 2012/05/02

Two scientific results of the Laboratoire d’Optique Appliqée (LOA) are highlighted in the May 2012 covers of Nature Physics and Nature Photonics. These two results on the attosecond control of plasma and on the generation of all-optical gammaray beam by Compton scatteringwere obtained by three teams of the laboratoryFLEX (X-ray source development and application), SPL (Particle source development and application) and PCO (Physics of optical cycleand using two LOA experimental facilitiesthe « Salle Jaune » infrastructure (30 TW femtosecond laserand the « Salle Noire » infrastructure (ultrafast laser of a few optical cycles and controlled in phase). More details can be found following the links:

-Attosecond Control of plasmas-

http://www.nature.com/nphys/index.html

https://loa.ensta-paristech.fr/specialnews.php

-All Optical gamma-ray beam-

http://www.nature.com/nphoton/index.html

https://loa.ensta-paristech.fr/news.php

News & Views article as well an interview related to the All Optical gamma ray beam experiment are also available.

 


Attosecond control of plasmas demonstrated

Edited: 2011/10/19

– Generating for the first time an ultrashort radiation in a controlled manner by the use of a plasma, Nature Physics –

To observe ultrafast phenomena such as the movement of electrons in the matter, researchers need sources capable of producing extremely short light pulse radiation and energy. Even if devices capable of emitting pulses in the attosecond (10-18 seconds) already exist, many teams are trying to push the limits of their intensity and duration. The team led by the Laboratory of Applied Optics (LOA, CNRS / ENSTA-ParisTech / Ecole Polytechnique), in collaboration with CEA-Saclay and the Laboratory for the Use of Intense Lasers (LULI, CNRS / CEA / Ecole Polytechnique / UPMC), succeeded for the first time, to accelerate and guide electrons in a controled manner in a plasma using a laser. These electrons excite the plasma, which then emits electromagnetic pulses to ultra short wavelengths in the range of extreme ultraviolet. The attosecond radiation energy can be used to probe the ultrafast electronic processes. This work is published in Nature Physics (online – March 26, 2012).

Read the CNRS press release.

 


Launch of 2 new ANR projects at LOA

Edited: 2012/02/17

Two new research programs selected by the French Ministery of Research (ANR), ILA and ROLEX, have been lauched at LOA this february, 2012.

The ILA project aims at pushing forward the development of compact laser-driven sources of particles and radiation by using the next generation of multi-PW lasers, and measuring laser-accelerated high energy (GeV) particles with innovative diagnostic approaches. It combines the expertise of the French LOA group in the particle acceleration field to the Romanian IFIN-HH expertise in high-energy accelerator beam and particle detection technology. It’s an ambitious proposal as it addresses the development of four key particle and radiation sources: electrons, ions, energetic radiation and neutrons.

The main objective of ROLEX is to numerically and experimentally investigate an innovative approach to produce the very first multi-microjoules monochromatic coherent femtosecond laser source in the 10-nm range enabling to overpass the current bottlenecks. Our approach is based on the guiding of frequency-doubled multi-TW laser driver focused into a high density plasma soft X-ray amplifier driven by ultrafast recombination pumping.
ROLEX brings together a unique combination of French laboratories from the « Plateau de Saclay » working on ultra-intense lasers, laser based X-ray sources, guiding of high intensity infrared laser pulses, and hydrodynamic and atomic physics (LOA, CEA, ISMO, LULI, LPGP).

 


« Equipements d’Excellence » ATTOLAB selected

Edited: 2011/12/25

The selection of the second round of national « Equipement of Excellence (EQUIPEX) » has just been released. Two projects in which the LOA is a partner, ATTOLAB and MORPHOSCOPE2, were selected. EQUIPEX are part of the operation « Investments for the Future » set up by the French Ministry of ResearchThey aim to provide France with scientific equipment of intermediate size (ie, between 1 and 20 million euros)which will benefit all areas of research. ATTOLAB’s goal includes the establishment of a new experimental center, based on the Paris-Saclay campus, dedicated to studies of ultrafast electron dynamics in areas such as atomic, molecular, chemical, solid state physics and plasma physics. It was awarded 5 million eurosThe CEA is the coordinator (SPAM) and the project gathers 9 partners. The LOA duty is to specifically set up systems for plasma physics. MORPHOSCOPE2 is an infrastructure project incorporating technological developments in microscopic imaging, storage and algorithmic analysis of datato advance the understanding of biological processes and in predicting their behavior according to genetic or environmental variationsIt is coordinated by the Ecole Polytechnique (LOB) and gathers around twenty partners.

Press release of the selected 36 national projects: here, with the two summaries ATTOLAB and MORPHOSCOPE2.

 


Spring-8 XFEL in operation

Edited: 2011/06/08

The SPring-8 Angstrom Compact free electron Laser (SACLA) came on line at the RIKEN Harima Institute. SACLA is the second laser of its type in operation, following LCLS at the U.S. Department of Energy’s SLAC National Accelerator Laboratory. Producing the world’s highest energy X-ray laser light, SACLA offers scientists a new tool for studying and understanding the arrangement of atoms moving extremely rapidly in various materials. The technology used makes this instrument more compact compared to the LCLS. On his side, LOA is developing new techniques based on laser-produced plasmas to make even more compact sources of intense ultrafast X-ray radiation.

xfel.riken.jp/information/index_en.html

 


RTRA Triangle de la Physique

Edited: 2011/03/07

The Triangle of Physics is a thematic research network (RTRA) in physical sciences, from fundamental physics to applied physics. It brings together around areas beyond the rifts caused by their membership in various organizations, a set of laboratories, staff and researchers in physics, localized on the geographic triangle Orsay-Palaiseau-Saclay. Triangle de la Physique contains more than 1,000 scientists spread in 43 laboratories. Its goals is to support research through several flexible programs such as funding for chairs, equipment, conferences or workshops, salaries of postdocs or visitors. The topics of intense femtosecond laser and applications such as the physics of laser-matter interaction and plasmas has been efficiently supported by the RTRA through the theme 6, which includes 12 laboratories like the LOA. The Review 2010 has just been released and confirms its strong impact on the scientific research teams. 4630 M € have been distributed to 90 selected projects with a rejection rate of 32% (over € 13 million requested). Nearly € 18 million have been awarded since 2007. The Triangle of Physics RTRA will continue its work until 2012, the date from which the projects of Laboratories of Excellence (LABEX) selected in 2011 will then play a major role for fundings.

 


large scale intense femtosecond laser funded

Edited: 2011/01/20

… The large scale intense femtosecond laser infrastructure CILEX  funded …

The CILEX large scale infrastructure project of intense femtosecond laser and applications has been selected (15 M € for construction) by the french Ministery of Research. Following the first funds received few years ago by the « contrat plan region » (CPER) funding agency, a laser system from 5 to 10 PW and its experimental areas of physics of laser matter interaction and plasmas are going to be built thanks to a collaboration between all the partners working in this field within the Plateau de Saclay campus (ILE, LULI, LOA, UPSUD, CEA, …). The infrastructure will be installed at l’Ormes des Merisiers, and will be surrounded by a set of “satellite facilities” operating laser systems at the 100 TW to 1 PW (LUIRE) energy level (LOA ‘Salle Jaune’, UHI100, LASERIX, LULI2000, ELFIE and LUIRE). They will be devoted to reduced‐scale relevant experiments, exploratory studies of novel concepts or applications based on laser‐matter interaction, and thanks to a versatile environment, training for students or scientific and technical staffs. They will allow to continue the development of the research on this scientific field during all the construction period. The infrastructure is expected to be delivered around 2015 for first users.

list of the selected projects

Attached document ]

 


LASERLAB, phase III

Edited: 2010/12/03

… LaserLab : phase III …   LASERLAB-EUROPE, the Integrated Initiative of European Laser Infrastructures, prepares for its third phase.

On November 25, only 18 months since the predecessor project was launched, LASERLAB-EUROPE (www.laserlab-europe.eu), submitted a proposal to the European Commission in response to the Call INFRA-2011-1.1.19. Laser sources. The EC expects applicants under this Call to provide and facilitate access to the key laser facilities in Europe in the area of high-field science and short-pulse spectroscopy. In addition, they should aim to integrate these facilities and resources with a long term perspective, and stimulate new scientific activities in view of future new advanced European Laser facilities such as the Extreme Light Infrastructure (« ELI ») and the High Power laser Energy Research facility (« HiPER »).

During its third phase, expected to last from 2012 through 2015, LASERLAB-EUROPE will comprise 28 of the largest European laser infrastructures, including the LOA laboratory. Together with subcontractors and associate partners it will cover 19 European countries. In a rapidly changing environment of laser science the project defines its position between the basis of university groups and users on the one hand, and the Pan-European facilities on the other, keeping very close ties with both.

LASERLAB-EUROPE was first to develop an integrated concept of Transnational Access under Consortium governance, employing an external selection panel to ensure ultimate scientific quality. The concept includes “Dynamic Access”, i.e. flexible redistribution of EC resources according to varying offers and/or demand. Under this scheme the Consortium will provide nearly 3000 days of Access to an estimated 500 users through research opportunities at 20 RIs from 11 countries. In its Joint Research Activities LASERLAB-EUROPE will react to new scientific developments, including those stimulated by ELI and HiPER. A total of four JRAs include innovative radiation sources at the extremes, charged particle acceleration with intense lasers, research on lasers for innovation, technology and energy, and laser and photonics for biology and health. The project is requesting a total of 10 Million Euros.

www.laserlab-europe.eu

 


Laboratoire d’Excellence PALM

Edited: 2010/11/04

As part of the french « Grand Emprunt » funding strategy, the LOA is one partner of the « Laboratoire d’Excellence » (LABEX) project  called PALM (Physics: Atoms, Light, Matter) sent to referees November 22, 2010. This project brings together almost 40 laboratories around the Saclay plateau selected in the field of physics. Topics covered within this LABEX are: Lasers, High intensity physics ; Plasmas, Atomic, Molecular and Optical Physics ; Condensed matter : mesocopic properties and transport ; Condensed matter : electronic and magnetic properties ; Soft matter ; Statistical and non-linear physics ; Physical chemistry

PALM wants to create a dynamic interaction between topics and different communities, and to provide all conditions for the emergence of new scientific themes. Its financial efforts will be at first concentrated on a small number of priority themes: correlated quantum systems, the slow dynamics and non-equilibrium systems, ultrafast dynamics and from the sources of radiation to the responses of multiscale in complex systems.

This last theme contains most of the activities of the LOA and aims to boost the interface between the community working on sources of radiations and particles, especially the ultra-fast laser sources, and communities using these tools to study the dynamics of the matter like in the diluted material (eg sub-femtosecond electron dynamics), the response in condensed matter (for example the study of strongly correlated systems by photoemission, the evolution of irradiated solids) or in the plasma phase, but also the biological functions studies (such as metabolism or photosynthesis) based on physico-chemical reactions associated with multi-scale processes of charge transfer or energy.

In addition to these topics, PALM will also propose a theme to be used specifically to promote the emergence of new ideas and scientific studies associated with high risks.

 


2011 national science festival at LOA

Edited: 2010/10/19

The LOA-ENSTA participates to the 2010 National Science Festival on Saturday, October 23 2010 from 14h to 18h. In collaboration with laboratories of the ENSTA Palaiseau campus, a guided tour through workshops presented by the research center shows how some complex physical phenomena can be approached quite easily from simple experiments and what are their implications in the daily life. Visitors can explore the world of optics and light through experiments showing the influence of Earth’s atmosphere on sunlight or measuring the speed of the expansion of the universe using the Doppler effect.

This event is an nice opportunity to educate young people about physics as well as advertising research careers.

 


40 years of research at ENSTA

Edited: 2010/07/12

ENSTA celebrates its 40th anniversary in 2010. The event will be celebrated Monday, October 11, 2010. Events highlighting the evolution of ENSTA since its creation, the major advances that ENSTA has achieved and the technological and scientific issues at the forefront of national and international research currently pursued will be presented. Kiosks and scientific courses organized by ENSTA laboratories will also be part of the event.

 


ENSTA-mobile back at LOA

Edited: 2010/06/01

ENSTA-Mobile is one of three existing portable intense femtosecond laser in the world. The originality of this laser system is its ability to be installed in other environments than usual laboratory hosting intense laser systems. Built by Amplitude technology for LOA and supported by a DGA contract, this system is currently on the site of LOA ENSTA-Palaiseau.

The project ENSTA-Mobile has started in 2009 with several objectives. One of them is to demonstrate the feasibility of a laser lightning rod in collaboration with EADS, Airbus and CILAS. In this context the ILM group at LOA  has achieved in October 2009 a test campaign on the site of CEAT in Toulouse (FRANCE). It was particularly noted that the guiding and triggering discharges of filaments was much more effective when applying a negative voltage polarity. It was also shown the ability of an arc filament to be trigged away from its natural attachment point.

 


Strong LOA partnership for the PW laser Project

Edited: 2010/05/04

Forte de sa tradition de recherche en développement laser, le LOA participe de manière soutenue au projet d’infrastructure laser PW sur le plateau de Saclay coordonné par le programme ILE.  Ce projet Francilien réunit 13 laboratoires. Il a pour objectif la mise à disposition à la communauté des physiciens de l’Interaction laser-matière à haut flux une infrastructure de recherche basée sur une source laser intense ultrabrève aux performances uniques au monde et ses sites expérimentaux.

Les missions du laboratoire LOA sont fondamentales dans ce projet. Le LOA assure un soutien majeur au niveau développement technologique, support technique et accompagnement scientifique. Le LOA a par ailleurs au sein du projet la charge de la construction du laser 1 PW, des modules d’amplification de la chaine laser 10 PW ainsi que la conception et la réalisation de l’ensemble des systèmes expérimentaux que les équipes de chercheurs vont utiliser pour réaliser leurs expériences. Le LOA a par ailleurs récemment démontré un injecteur laser pour les systèmes de classe PW à très haut contraste temporel dans le cadre de ce projet.

 


Le plateau de Saclay se structure

Edited: 2010/03/31

Le Grand emprunt national, la Fondation de coopération scientifique, les RTRAs, le projet de grand établissement ParisTech, le Plan Campus, la relocalisation sur site d’Ecole d’Ingénieurs prestigieuses et d’université, le transfert de gros laboratoires de recherche et d’industriels sont autant de signes tangibles de la création sur le plateau de Saclay d’un centre de grande envergure. L’objectif affiché du gouvernement est de réaliser le plus important campus scientifique et technologique européen (plus de renseignements dans la pièce jointe ci-dessous).

La thématique laser intense et applications est bien représentée et soutenue dans ces perspectives d’évolutions. Le LOA-ENSTA (Philippe Zeitoun) coordonne le pôle Optique-Laser-Plasma du groupe ParisTech dont un des objectifs est de proposer les lignes directrices pour l’évolution de ce domaine scientifique et les propositions de projets pour répondre à l’appel d’offre du Grand Emprunt National (Equipements d’excellence, Laboratoires d’excellence, etc…).

Attached document ]

 


La lumière quantique

Edited: 2010/02/28

Le magazine « La Recherche » consacre un dossier spécial intitulé « La lumière quantique » sur les lasers et leurs applications (numéro 38, Février 2010). Des plus petits aux plus gros lasers du monde, de la science fondamentale aux applications militaires ou sociétales, les articles rappellent que le laser a révolutionné l’optique et la manière d’explorer les propriétés de la matière.

La physique des plasmas avec les lasers intenses femtosecondes, le rayonnement X ultrabref, les mouvements ultrarapides de la molécule au noyau, l’accélération de particules énergétiques, la chirurgie des yeux, le guidage plasma de laser intense sont autant de thèmes abordés dans ce dossier spécial, thèmes qui constituent les activités phares du Laboratoire d’Optique Appliquée implanté sur le site de l’ENSTA-ParisTech.

 


6.5 M€ pour la protonthérapie par laser

Edited: 2010/02/06

L’Agence française OSEO vient d’accorder 6,257 millions € à SAPHIR, un projet national qui est porté par Amplitude Technologies, et dont le Laboratoire d’Optique Appliquée ENSTA – X – CNRS est le partenaire qui accueillera l’installation laser et l’infrastructure expérimentale à l’ENSTA-Palaiseau.

SAPHIR a pour finalité l’étude de la faisabilité de la production par laser d’un faisceau de protons de 200 à 240 MeV destiné au traitement du cancer. Cette technique, qui est déjà utilisée au centre de protonthérapie d’Orsay (CPO) de l’Institut Curie, permet un traitement efficace du cancer, mais elle reste onéreuse et tout développement qui réduirait le coût de cette approche serait bénéfique. L’approche par laser, si elle est démontrée, répondrait à un besoin sociétal important.

5 laboratoires et institutions français (LOA, CPO/Institut Curie, Institut Gustave Roussy, CEA DAM / LIRM et CEA Saclay IRAMIS) et 4 partenaires industriels (Amplitude Technologies, Dosisoft, Imagine Optic et Propulse SAS), interviennent dans SAPHIR, projet interdisciplinaire, qui relie physique, biologie, oncologie, une large part étant faite aux transferts de technologie de la recherche fondamentale vers l’industrie. Le LOA est également coordinateur scientifique « Accélération de particules par plasma-laser ».

Pour plus d’information, voir la pièce jointe ci-dessous.

Attached document ]

 


2010: les 50 ans du Laser

Edited: 2010/01/04

Le laser à 50 ans en 2010. La cérémonie de lancement des festivités s’est déroulée au Palais de la Découverte le 7 janvier 2010 sous l’égide de la Société Française d’Optique et la Société Française de Physique. Le 16 mai 1960, Theodore Maiman fit fonctionner le premier laser au Hughes Research Laboratory à Malibu (Californie) et ce résultat fut publié trois mois plus tard dans la revue « Nature » après une tentative infructueuse à Physical Revue Letters. Il s’en suivit des décennies de recherche académique et industrielle sur la physique des lasers et sur les nombreuses applications.

Une intense compétition faisait rage à cette époque suite à la proposition en 1958 du maser optique par Charles Townes de l’université de Colombia et par Arthur Schawlow des Bell Labs. Théodore Maiman, un outsider dans cette compétition entre grandes universités, eut l’idée d’utiliser une puissante source d’énergie (un flash) afin d’exciter optiquement les atomes d’un cristal de synthèse. Contrairement à ses collègues Schawlow et Townes, qui utilisèrent le gaz pour le maser, Maiman fit le pari d’utiliser un solide : du rubis dopé avec des ions de chrome. Le premier laser à gaz suivra rapidement (Hélium-Néon réalisé par A. Javan des Bell Labs en 1961)

 


2009 : les 35 ans du LOA à l’ENSTA Palaiseau

Edited: 2009/12/03

Le LOA fête en 2009 ses 35 ans d’activités scientifiques sur le site de l’ENSTA Palaiseau. Issu d’une chaire de Physique de l’Ecole Polytechnique (implantée à Paris) en 1960 attribué au Professeur Vignal, l’activité Etudes des lasers et de leurs applications amène à la création du LOA en 1972 comme laboratoire commun Ecole Polytechnique – ENSTA. Le LOA devient ensuite Unité Mixte Associée INSERM en 1984 et Unité Mixte Associée CNRS en 1989.

Le LOA rentre de plein fouet dans le domaine des lasers ultrabrefs à la fin des années 1970 en mettant au point le premier laser sub-picoseconde français (laser à colorant) grâce à une collaboration entre l’équipe du LOA (A. Antonetti, G. Grillon, G. Hamoniaux, A. Migus) avec C. Shank et E. Ippen alors aux Bell Labs. Puis en 1988, le directeur du LOA A. Antonetti, avec l’impulsion de M. Gavrila et P. Agostini du CEA, a obtenu le financement d’un premier programme européen « Esprit et Stimulation »  pour réaliser au laboratoire le premier laser femtoseconde intense français. Le LOA fut également à cette époque le deuxième laboratoire au monde, après la première démonstration par W. Sibbett (Angleterre), à réaliser le blocage de mode par effet Kerr qui est un processus clé pour la réalisation de lasers femtosecondes efficaces.  Enfin, un partenariat soutenu avec le laboratoire LULI de l’Ecole Polytechnique au début des années 1990, a permis de lancer l’activité de physique de l’interaction laser plasma au LOA dans le régime femtoseconde intense.

Le LOA a depuis cette date continué de jouer un rôle de pionnier dans le développement des lasers intenses ultrabrefs et de leurs applications. Ses succès scientifiques accompagnés par une forte tradition de recherche de contrats, et notamment européens, ont également amené à la création de spin off du laboratoire à partir de ses équipes : le laboratoire CELIA à Bordeaux, le LOB à l’Ecole Polytechnique, l’ILE sur le plateau de Saclay. Le LOA est devenu Unité Mixte de Recherche (UMR) en 1997 et continue à se développer. Il compte actuellement 7 groupes de recherche et 90 personnes.

 


Fête de la Science au LOA-ENSTA ParisTech

Edited: 2009/10/31

Le LOA-ENSTA Paris Tech a participé à la Fête de la Science 2009 qui s’est tenue le vendredi 20 novembre toute la journée et le samedi 21 novembre de 14h à 18h. Plus de 200 visiteurs ont pu découvrir le monde de la recherche dans une atmosphère chaleureuse et conviviale. En collaboration avec les laboratoires ENSTA du site de Palaiseau, une visite guidée au travers d’ateliers proposés par le centre de recherche a montré comment certains phénomènes physiques complexes peuvent s’appréhender assez facilement autour d’expériences simples et quelles sont leurs implications dans la vie courante. Les visiteurs ont découvert le monde des lasers, des sources lumineuses très intenses; mais également des expériences de détermination de la température de la surface du soleil à partir de la mesure d’énergie lumineuse; la mesure de la vitesse d’expansion de l’univers (effet doppler); la détermination de la position d’une étoile (effet mirage). Ces portes ouvertes sont aussi l’occasion de sensibiliser les jeunes à la physique en expliquant le métier de chercheur et les métiers autour de la recherche. Le programme de la fête de la science 2009 sur le site de l’ENSTA-Palaiseau est disponible ci-dessous.

Attached document ]

 


Prix Académie des Sciences au LOA

Edited: 2009/10/01

Les lauréats du prix fondé par l’état de l’ Académie des Sciences 2009  a été attribué à François Amiranoff, directeur de recherche au CNRS, directeur du Laboratoire Utilisation des lasers intenses (LULI) à l’École Polytechnique, Victor Malka, directeur de recherche au CNRS, responsable de l’équipe Source de particules par laser (SPL) au Laboratoire d’optique appliquée (LOA) de l’École Nationale Supérieure des Techniques Avancées (ENSTA), et Patrick Mora, directeur de recherche au CNRS, directeur du Centre de physique théorique de l’École Polytechnique.

Ce prix a été créé en 1795 et est doté de 7600 euros. Depuis 1997, le prix est quadriennal alternativement pour les quatre disciplines suivantes : mathématique, physique, chimie, biologie animale et végétale. Il sera remis le 24 novembre 2009 à l’Institut de France.

www.academie-sciences.fr/prix/prix_2009.htm

 


Prix de Thèse 2009 au LOA

Edited: 2009/09/14

Aurélien Houard s’est vu attribué un des 10 prix de thèse de l’Ecole Polytechnique 2009 pour ses travaux sur la filamentation laser femtoseconde. Son travail de thèse, effectué au Laboratoire d’Optique Appliquée sous la direction d’André Mysyrowicz s’intitule « Filamentation laser femtoseconde dans l’air et application au guidage de décharges électriques et à la génération de rayonnement THz ».

Les résultats expérimentaux obtenus et leur analyse lui ont permis de mettre à jour des applications totalement nouvelles de la filamentation laser, comme la génération de rayonnement Terahertz intense ou le captage de forts courants. Ainsi, après avoir caractérisé et expliqué la source du rayonnement Terahertz des filaments, il a démontré que sous l’effet de certains champs statiques les filaments pouvaient constituer l’une des sources de rayonnement THz ultracourt les plus intenses qui soient, ouvrant la voie vers des régimes d’interaction nonlinéaires THz. Il a par ailleurs montré, dans le cadre du projet européen Téramobile et en collaboration avec la SNCF, que ces mêmes filaments pouvaient capter de forts courants sans contact mécanique et avec un minimum de pertes en initiant des décharges très conductrices. Une propriété qui pourrait être utilisée pour l’alimentation des trains à grande vitesse.

Le prix lui a été remis le 29 mai à l’Ecole Polytechnique par le Professeur Jean WEISSENBACH, médaille d’or du CNRS et généticien de renommée internationale à l’origine de la première carte génétique humaine de haute résolution (voir photo, zoom disponible).

 


3 scientifiques confirmés récompensés

Edited: 2009/06/05

Le European Research Council met à l’honneur la thématique des lasers femtosecondes intenses et de ses applications en récompensant 3 scientifiques confirmés européens pour développer leurs projets sur la génération de rayonnement X ultrabref et la physique attoseconde (Anne L’Huillier), le développement d’accélérateurs compacts de particules par laser (Victor Malka), et l’utilisation des sources X femtosecondes et la spectroscopie X ultrarapide (Willy Sundström).

Ces prix prestigieux sont accompagnés d’importants financements de plus de 2 M€ afin de récompenser des scientifiques ayant accomplis des travaux de recherche exceptionnel dans leur domaine d’expertise et afin d’encourager la prise de risque dans le développement de projets multidisciplinaires.

Le projet ERC du LOA vient de démarrer, le 1er mai 2009.