J.M. Ortega

• Managing Director at University of Paris-Saclay

l'utilisation du rayonnement infrarouge intense et accordable produit par un laser à électrons libres permet de « chauffer » des ions moléculaires dans des états vibrationnels très excités. Lorsque la longueur d'onde du laser est en résonance avec une transition vibrationnelle de l'ion, l'absorption successive d'un grand nombre de photons se poursu...

We measured the interferences of the coherent radiation, produced by a train of electron bunches in an undulator and stored in an optical cavity. The device used here is a free-electron laser, whose optical cavity stores the radiation pulse for a multipass amplification process. The amplification process is avoided by detuning the optical cavity. T...

The purpose of this study is to extend the spectral range of a differential method of infrared micro-spectroscopy in order to allow the accurate detection of nanoparticles of interest for biomedical applications. Among these, metal–organic framework (MOF) nanoparticles have attracted increasing interest due to their capacity to incorporate high dru...

CLIO is a Free Electron Laser based on a thermionic electron gun. In its normal operating mode it delivers electron 8 pulses but studies are ongoing to shorten the pulses to about 1 ps. We report on simulations showing how the pulse can be shortened and the expected signal yield from several bunch length diagnostics (Coherent Transition Radiation,...

Sciences ACO is a non-profit association based in Orsay (France). It manages a Museum of Light and Matter visited by more than 1,000 people each year. In this unique place, scientists and cultural mediators preserve, exhibit and comment on items of the history of science & technology, to pass on the knowledge of this heritage to the audience. Scien...

The infrared free-electron laser (FEL) offers a large tunability since the FEL gain remains high throughout the infrared spectral range, and the reflectivity of metal mirrors remains also close to unity. The main limitation comes from the diffraction of the optical beam due to the finite size of the vacuum chamber of the undulator. A solution is to...

We report the characteristics of a simple complementary metal-oxide-semiconductor compatible terahertz detector device with low response time (nanoseconds) determined using a short-pulse, high intensity free-electron laser. The noise equivalent power was 1 × 10−11 W Hz−1/2. The detector has an enhanced response over narrow bands, most notably at 9....

The infrared free-electron laser offers a large tunability since the FEL gain remains high throughout the infrared spectral range, and the reflectivity of metal mirrors remains also close to unity. The main limitation comes from the diffraction of the optical beam due to the finite size of the vacuum chamber of the undulator. A solution is to use t...

We have extended the spectral range of a differential method of infrared microspectroscopy in order to operate in the terahertz spectral region. We show on samples of graphite embedded in a matrix of polymers that the spatial resolution is practically independent of the wavelength and is at least . This method aims at performing “chemical mapping”...

We have studied the electron beam transverse adaptation in an FEL oscillator in a very large interval of wavelength (3 to 150 μm) and electron energy range (12 to 45 MeV). Beam dimensions are measured by a moving wire whose temperature dependent resistivity is monitored. By a fast motion of the wire we measure its temperature increase at each trans...

In a scope of a collaboration between Thales Communications & Security and CEA DAM DIF, 11 keV Xrays were produced by inverse Compton scattering on the ELSA facility. In this type of experiment, X-ray observation lies in the use of accurate electron and laser beam interaction diagnostics and on fitted X-ray detectors. The low interaction probabilit...

We show that a commercial atomic force microscope can be used at room temperature as a detector throughout the infrared spectrum simply by recording the induced oscillation of its cantilever after irradiation by a pulsed laser. The oscillation amplitude can be made larger by spraying an absorbing graphite layer on the tip side. We demonstrate that...

In this paper, we will employ two microscopy techniques, transmission electron microscopy and infrared nanospectromicroscopy, to study the production of polyhydroxybutyrate in Rhodobacter capsulatus and to evaluate the influence of glucose and acetone on the production yield. The results overlap which leads us to a consistent conclusion, highlighti...

To optimize the detection of an 11 keV X-ray beam produced by Inverse Compton Scattering at the ELSA facility, with a 17 MeV electron beam and a 532 nm laser, we demonstrate the use of a very sensitive detection scheme, based on a radio luminescent screen (imaging plate) used in the spontaneous emission regime. It has proven to be very sensitive an...

Some like it hot! The photothermally induced resonance technique, in which an AFM microscope is coupled to a tunable pulsed IR laser, allows IR mapping and gives access to local IR spectra at the subcellular level. A metal-carbonyl compound was internalized in cells and detected in the cell nucleus thanks to its IR signature. The local IR spectrum...

Absorption of single InGaAs self-assembled quantum dots is spatially resolved in resonance with the S to P polaron transitions around λ=25 μm wavelength. We show that the spatial resolution down to 50 nm (λ/500) combined with the analysis of the absorption nanoscopy images provides a measurement of the homogeneous broadening at room temperature. Th...

We have investigated the mid-infrared spontaneous and stimulated emission between confined subbands in the conduction band of GaAs/AlGaAs quantum wells. The carriers which give rise to the intersubband emission are excited in the upper subbands using an intersubband optical pumping in coupled asymmetric quantum wells. The quantum wells are designed...

An X-ray Compton source is under development at the ELSA facility. The electron beam coming from the ELSA linear accelerator interacts with a laser beam to generate an X-ray flux in the direction of the electron beam. With a 17MeV electron beam and a 532nm laser, the resulting X-ray maximal energy is around 11keV. The beams visualization at the int...

We have employed atomic force microscope-based infrared spectroscopy (AFM-IR) to spatially map energy storage polymers inside individual bacteria Rhodobacter capsulatus. AFM-IR allows chemical mapping of sub-cellular features with a spatial resolution of <100 nm. We have used key absorption bands of the energy storage polymer polyhydroxybutyrate (P...

We have used an AFM microcantilever as a far infrared detector. When hit by a pulsed laser, the cantilever starts damped oscillations which amplitude can be recorded and laser spectra can be recorded at λ > 25 μm which is the limit of 77K HCT detectors. We discuss the performances of this device.

We present measurements and numerical simulations of the laser beam transverse profile of the CLIO infrared free-electron laser (FEL). This FEL uses a hole coupling extraction system, which introduces important perturbation on the intracavity optical mode. We show that this intracavity mode tends to avoid the extraction hole and that the output pow...

A study of a Compton source for X-rays in the ELSA facility is in line with the RADIOTHOMX project (THALES Communication, Colombes, France). The goal of this project is to develop a compact device to deliver an intense flux of monochromatic X-rays for medical applications. Thanks to its low emittance (3μm normalized r.m.s) with high current electro...

Midinfrared absorption can be locally measured using a detection combining an atomic force microscope and a pulsed excitation. This is illustrated for the midinfrared bulk GaAs phonon absorption and for the midinfrared absorption of thin SiO2 microdisks. We show that the signal given by the cantilever oscillation amplitude of the atomic force micro...

A phenomenon of ``spectral gaps'' is observed in far-infrared free-electron lasers using partial waveguiding: the laser power falls down to zero at some particular wavelengths, whatever the beam adjustments are. We show that this effect is related to a periodic increase of the cavity losses, with a period depending on the dimensions of the waveguid...

We have performed IR spectromicroscopy of cells immersed in liquid water, with a lateral resolution better than 100 nm . Here, we use the motion of an atomic force microscope tip, probing the local transient deformation induced by an IR pulsed laser tuned at a sample absorbing wavelength. By Fourier analysis of the vibration of the cantilever tip,...

We show that an infrared spectromicroscopy method based on a photo-thermal effect, is able to localize single viruses as well when they are isolated and when they are located inside the bacteria they have infected. In this latter case, although the topography performed by an AFM cannot image the viruses, the AFMIR is able to do so. In addition, we...

We show that we can measure the room temperature ultraweak absorption of a single buried semiconductor quantum dot. This is achieved by monitoring the deformation field induced by the absorption of midinfrared laser pulses and locally detected with an atomic force microscope tip. The absorption is spectrally and spatially resolved around lambda app...

In this paper, we analyze in detail a new method of infrared micro-spectroscopy, which aims at performing "chemical mapping" of various objects with sub-wavelength lateral resolution by using the infrared vibrational signature characterizing different molecular species. Its principle consists in an atomic force microscope tip, probing the local tra...

Coordination complexes of the magnesium nitrate cation with water [MgNO(3)(H(2)O)(n)](+) up to n=7 are investigated by experiment and theory. The fragmentation patterns of [MgNO(3)(H(2)O)(n)](+) clusters generated via electrospray ionization indicate a considerable change in stability between n=3 and 4. Further, ion-molecule reactions of mass-selec...

The Orsay storage ring free-electron laser has been operated in the short–wave-length side (blue) of the visible spectral range from 4630 Å to 4860 Å. General conclusions on storage ring free-electron laser are derived after our successive operations of a tunable laser over almost the entire visible spectral range.

We report the first generation of vacuum-ultraviolet harmonics of an external laser focused on an ultrarelativistic electron bunch circulating in a periodic magnetic field. The amplification of the undulator emission at the 3rd (at 1773 Å) and 5th harmonics (at 1064 Å) of a doubled neodymium-YAG laser (at 5320 Å) has been observed in our optical kl...

The first results of commissioning for the French Synchrotron Radiation Facility SOLEIL at 2.75 GeV are presented. Perspectives for the fourth generation light source based on the ARC-EN-CIEL project are described.

ARC-EN-CIEL (Accelerator-Radiation Complex for Enhanced Coherent Intense Extended Light) proposal is based on a CW 1 GeV superconducting linear accelerator delivering high charge, subpicosecond, low emittance electron bunches with a high repetition rate (1 kHz). The FEL uses High Harmonics Generation in gases in a High Gain Harmonic Generation sche...

A three level scheme based on S–P polaron intersublevel transitions in n-doped InAs/GaAs self-assembled quantum dots is proposed to obtain laser effect around 25 µm wavelength under optical pumping. Temperature dependence of the optical gain is theoretically analysed. Lasing effect is expected up to 300 K. To probe the T2 decoherence time, one of t...

The infrared free-electron laser offers the advantage of a potential large tunability since the FEL gain itself remains substantially high throughout the infrared spectral range, and the reflectivity of metal mirrors used in the optical cavity remains also close to unity. The main limitation comes from the diffraction of the optical beam due to the...

We describe a new method of infrared micro-spectroscopy. It aims at performing “chemical mapping” of various objects with sub-wavelength lateral resolution, by using the infrared oscillatory signature characterizing different molecular species. Here, we use an atomic force microscope tip, probing the local transient deformation induced by an infrar...

Ethanol tolerance, ATPase activity and the lipid composition of the plasma membrane to study potential relationship among them were examined in five different wine yeast strains. Yeast cells were subjected to ethanol stress (4% v/v). Principal component analysis of the results revealed that the wine yeasts studied can be distinguished in terms of A...

The protonated leucine methyl ester structure was probed using mid-infrared multiphoton dissociation (IRMPD) spectroscopy performed at CLIO, the Orsay Free Electron Laser facility. A first experimental spectrum was obtained with a Fourier-transform ion-cyclotron-resonance mass spectrometer with ions generated through a MALDI process. A second spect...

The infrared free-electron laser CLIO is tunable from 3 to 150 μm by operating its driver RF linear accelerator between 50 and 12 MeV. This is the largest spectral range ever obtained with a single optical cavity. We have studied the electron beam transverse adaptation in the FEL undulator throughout the spectral and energy range. Each beam dimensi...

ARC-EN-CIEL (Accelerator-Radiation for Enhanced Coherent Intense Extended Light) aims at providing the user community with coherent femtosecond light pulses covering from UV to soft X ray in France. It is based on a CW 1.3 GHz superconducting linear accelerator delivering high charge, subpicosecond, low emittance electron bunches at high repetition...

We report an investigation on THz signal detection using plasma instabilities in two-dimensional electron gas of a tensile strained silicon quantum well of Si/SiGe hetero-FET. It is, to our knowledge, the first measurements of THz nonlinear behaviour in such silicon-based devices. We discuss the key parameters which are controlling detection and os...

We describe a new method of infrared microspectroscopy. It is intended for performing chemical mapping of various objects with subwavelength lateral resolution by using the infrared vibrational signature characterizing different molecular species. We use the photothermal expansion effect, detected by an atomic force microscope tip, probing the loca...

The French project of a fourth generation light source, ARC-EN-CIEL (Accelerator-Radiation for Enhanced Coherent Intense Extended Light), is a unique facility providing the user community with coherent femtosecond light pulses covering the UV, VUV and soft X ray spectral range. It is based on a CW 1 GeV superconducting linear accelerator delivering...

The French project of a fourth generation light source, ARC-EN-CIEL (Accelerator-Radiation for Enhanced Coherent Intense Extended Light), is a unique facility providing the user community with coherent femtosecond light pulses covering the UV, VUV and soft X ray spectral range. It is based on a CW 1 GeV superconducting linear accelerator delivering...

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We report on polaron dynamic measurements in InAs/GaAs semiconductor quantum dots. The polaron dynamics is monitored by transient nonlinear spectroscopy by recording the transmission variation as a function of the pulse area of an infrared picosecond excitation. A non-monotonous transmission is observed for pulse areas larger than a pi pulse. We at...

The effect of glucose and dissolved oxygen in a synthetic medium simulating the standard composition of grape juice on the production of ethyl acetate and isoamyl acetate by a Saccharomyces cerevisiae strain during alcoholic fermentation was studied. The specific in vitro activity of alcohol acetyltransferase (AATase, EC 2.3.1.84) and esterases (ES...

This paper describe the recent measurements of `Electron efficiency' which has been done with the `CLIO' Free-electron laser (FEL). The `Electron efficiency' is the relative energy loss of the electron beam in the undulator during the FEL interaction. It gives an absolute measurement of the optical power produced by the FEL, which is then compa...

We have investigated by pump–probe spectroscopy the spectral and power dependences of the polaron decay in n-doped InAs/GaAs self-assembled quantum dots. The polaron which results from the strong coupling for the electron–phonon interaction in the dots is studied in the spectral range between 58 and 64 meV. We show that besides the initial polaron...

Human skin sections were studied using synchrotron-powered infrared microscopy. The superior lateral resolution achieved with this technique (diffraction-limited spot sizes) allows the detailed analysis of the biocomposition of the skin layers. It is shown that highly organized lipids are present in the stratum corneum, as evidenced by a slight fre...

Infrared spectra in the mid-infrared region (800-1600 cm(-1)) of highly unsaturated Fe(+)-hydrocarbon complexes isolated in the gas phase are presented. These organometallic complexes were selectively prepared by ion-molecule reactions in a Fourier transform ion cycloton mass spectrometer (FTICR-MS). The infrared multiphoton dissociation (IRMPD) te...

We studied the vibrational coherence of DCl molecules and clusters embedded in solid nitrogen by means of photon echo experiments using the CLIO-FEL. Infrared vibrational spectra of the samples exhibit numerous absorption bands assigned to different species in the 2080–2020 wavenumber range. The tunability of the laser source in terms of spectral r...

This paper shows the new results obtained with the CLIO infrared FEL. The spectral range of the CLIO FEL has recently been extended, and it is now spanning from λ=3–120 μm. We present here some features obtained with CLIO at large wavelengths. We show also measurements of electron energy spectrum after FEL interaction, and we make a comparison with...

Protonated dialanine cations have been isolated in a Fourier transform ion cyclotron resonance mass-spectrometer (FT-ICR-MS) and subjected to infrared multiphoton dissociation (IRMPD) at the free electron laser facility CLIO in Orsay (France). The spectral dependence of the IR induced fragmentation pattern in the mid-infrared region (800–2000 cm−1)...

In photothermal beam deflection (PTBD) spectroscopy generating and detection of thermal waves occur gener-ally in the sub-millimeter length scale. Therefore, PTBD provides spatial information about the surface of the sam-ple and permits imaging and/or microspectrometry. Re-cent results of PTBD experiments are presented with a high spatial resolutio...

Low concentration of toxic radioactive metals in environmental samples often limits the interpretation of results of infrared studies investigating the interaction processes between the metal ions and environmental compartments. For the first time, we could show that photothermal infrared spectroscopy performed with a pulsed free electron laser can...

The traditional biological process by which sherry wines are aged can be accelerated by using submerged Saccharomyces cerevisiae var. capensis (G1) strain cultures previously grown in glycerol. The used controlled shaking conditions raise the acetaldehyde, acetoin, and meso 2,3-butanediol contents in the wine, and increases the consumption of gluco...

First example of coupling a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FTICR-MS) with an infrared Free Electron Laser (FEL) is presented. This experimental setup is ideally suited for the direct structural characterization of reactive polyatomic ions. Ultrasensitive measurements of the infrared vibrational spectrum of ionic reacti...

We have investigated various optical non-linearities in resonance with intersublevel transitions in InAs/GaAs self-assembled quantum dots. The infrared pulses were delivered by CLIO at Orsay (France) and enabled (i) the evidence of second-harmonic generation with giant susceptibilities, (ii) the first measurement of a 70 ps long polaron lifetime th...

Polaron dynamics in n-doped InAs/GaAs self-assembled quantum dots is investigated using far infrared pump–probe spectroscopy around 22 μm wavelength of the s–p intersublevel transition. Despite the strong coupling between the confined electron and the phonon continuum, forming a priori an everlasting polaron, we show experimentally that the polaron...

Various pump–probe application experiments that can be done with infrared FELs and with table-top lasers are described. The spectral ranges that can be reached with these lasers and their spectral width and pulse length are briefly discussed. Many interesting experiments can be performed by using different wavelengths either with a two-color FEL or...

We report on the heat distribution inside a p+-InAsSb(Zn)/n-InAsSbP/n-InAs planar structure, emitting at 4.3 μm at 300 K. The experimental setup consists of both an infrared scanning microscope and a fiber tip as remote heat sensors (spatial resolution of some μm) operating in a time-resolved (10 μs temporal resolution) manner in the 3–5 μm spectra...

Formation of ethyl acetate and isoamyl acetate by seven wine yeast strains in a model grape juice was examined during fermentation. The amounts in which the two esters are produced during fermentation were found to depend on the particular yeast strain, its specific production rate and its rate of survival in the wine.Kloeckera apiculata exhibited...

The first example of direct structural characterization of polyaromatic ions by coupling a Fourier transform ion cyclotron resonance mass spectrometer with an infrared free-electron laser is presented. Measurement of the IR spectra of selectively prepared ionic reactive intermediates is allowed by the association of the high peak power and wide tun...

The cellular lipid composition of one flor-forming strain of Saccharomyces cerevisiae during fermentation and the subsequent period of film formation with different oxygen levels was studied. Irrespective of fermentation conditions, only those yeasts which came into contact with oxygen after fermentation formed a flor film. After the fermentation,...

We have performed time-integrated degenerate four-wave mixing experiments in InAs/GaAs self-assembled quantum dots. The quantum dots are excited in resonance with an intersublevel transition between the valence states of the dots. The dephasing time T2 is deduced from the time dependence of the photon echo amplitude as a function of the delay betwe...

The influence of the environment on vibrational dynamics, and especially on the vibrational dephasing time, is investigated for a simple system : DCl in a van der Waals solid (N2 lattice). Photon echo experiments are performed using the infrared free electron laser CLIO. In solid nitrogen, decay times of the third order polarization are in the pico...

Saccharomyces cerevisiae, races cerevisiae and capensis were used to carry out fermentations of grape musts with and without initial oxygen, in order to study changes in the production of higher alcohols and esters. After fermentation of the musts without initial oxygen, both yeast races produced lesser concentrations of the earlier-mentioned compo...

We have investigated the polaron dynamics in n-doped InAs/GaAs self-assembled quantum dots by pump-probe midinfrared spectroscopy. A long T1 polaron decay time is measured at both low temperature and room temperature, with values around 70 and 37 ps, respectively. The decay time decreases for energies closer to the optical phonon energy. The relaxa...

We study the influence of a partially guided propagation in the CLIO infrared FEL, both theoretically and experimentally. The waveguide is of planar type, guiding only in the vertical plane, and it is limited to the undulator length. The light propagation in the rest of the cavity is in free space. Therefore, the laser mode is in an intermediate re...

The CLIO laser is working as an open users facility. Most studies up to recently were restricted to the infrared range: λ = 3-15 μm (20-100 THz), rather than Terahertz. But continuous upgrade of the laser has extended the tuning range to 3-100 THz and should achieve 2-100 THz in a near future, enabling to consider CLIO as a true Terahertz radiation...

We study the conditions to perform micro-spectroscopy with a sub-wavelength lateral resolution in the wavelength spectral range from 3 to 20 μm, taking advantage of the infrared spectral signature of different chemical species. We utilised CLIO, a free electron laser, as the photon source. The transmitted photons were collected by either fluoride o...

We have investigated the second-harmonic generation with the conduction states of InAs/GaAs self-assembled quantum dots. The harmonic generation is resonant with intersublevel transitions, and in particular with the s-p transition. This transition, polarized along the [110] and the [-110] directions, exhibits a large dipole matrix element (3 nm). T...

Intersublevel second-order nonlinear susceptibility is investigated in InAs/GaAs self-assembled quantum dots. It is shown that the nonlinear susceptibility associated with intersublevel transitions in the conduction band or in the valence band can be greatly enhanced by up to six orders of magnitude as compared to the susceptibility of bulk GaAs. T...

The microscopic origin of the pseudo-gap state in high-Tc superconductors is still controversial. Experiments measuring the photo-induced response in the near-IR range (1.5 eV) seem to indicate that the physics controlling the pair-breaking process in the superconduting phase is reproduced in the normal state. This suggests the existence of preform...

Saccharomyces cerevisiae race cerevisiae was used to ferment grape musts in strictly anaerobic conditions, subjected to a prefermentative treatment of skin maceration and following a short aeration after 48 h of fermentation. Skin maceration caused an increase in the cellular phospholipid content which affected neither viability nor the fermentativ...

The free-electron laser ("FEL") has proven to be an invaluable source of radiation in the UV to far infrared spectral ranges. It is based on the amplification of an optical wave by a high energy electron beam oscillating transversely to its propagation. In the last decade, several FELs have been designed and built as user dedicated facilities. Pres...

Infrared picosecond accumulated photon echo experiments have been performed for the first time, using the Orsay Free Electron Laser, on the $v\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0$\rightarrow${}v\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1$ transition of CO in solid nitrogen. The vibrational dephasing time is found to be exce...

The optical gain of the infrared FEL “CLIO” has been increased at low electron energy by modifying the gun pulser. Therefore, the power emitted at long wavelengths (larger than 25μm) has been increased by more than an order of magnitude and the maximum wavelength, initially at 50μm, has been extended to 60μm. Measurements of laser and cavity extrac...

One color pump–probe and photon-echo experiments have been performed on the CO stretching mode of W(CO)6 at about 1982 cm−1 in organo-mineral xerogels. Over the whole temperature range studied, from room temperature to 5 K, the population lifetime T1 remains constant when the vibrational dephasing time T2 lengthens slightly. The temperature evoluti...

We have studied second-harmonic generation at midinfrared wavelengths in InAs/GaAs semiconductor self-assembled quantum dots. We show that resonant second-harmonic generation associated with the intraband transitions of the quantum dots can be achieved in p-type samples. Frequency doubling is observed both for a TM- and a TE-polarized infrared exci...

We have investigated the second-order nonlinear susceptibility in self-assembled quantum dots. The nonlinear susceptibility associated with intraband transitions in the conduction band and in the valence band is theoretically estimated for lens-shaped InAs/GaAs self-assembled quantum dots. The confined energy levels in the dots are calculated in th...

Ablation of human tissue with an infrared laser tuned to the amide II band of proteins has proven to be especially efficient, with reduced collateral damage. In order to check for a specific non-thermal effect at this wavelength, we have irradiated pig tissues at different frequencies, corresponding to the amide I, amide II and phosphate ones, with...

Resonant second-harmonic generation is reported in InAs/GaAs self-assembled quantum dots. Frequency doubling is observed between confined states in the valence band of the quantum dots. The second-order nonlinear susceptibility is maximum at 168 meV (7.4 μm wavelength) and is observed for an in-plane polarized excitation. A value of χzxx(2) as larg...

Enhancement of the 2nd and 3rd harmonic of the wavelength of a Free-Electron Laser (FEL) has been measured when a single electron beam is crossing a two-section undulator. To produce the harmonic radiation enhancement, the undulator is arranged so that the resonance wavelength of the 2nd undulator (downstream) matches a harmonic of the 1st undulato...

Urea, ammonium, arginine and ornithine contents after fermentation and biological aging of wine for two Saccharomyces cerevisiae strains with different O2 levels were analysed. Yeast growth and the excretion or uptake of urea were both dependent on yeast strain and the fermentation conditions. Based on these results, flor yeasts can metabolize the...

The CLIO-2 or ETOILES project is the envisioned extension of the CLIO facility, aimed at covering the far-infrared range between 50 μm and 1 or 2 mm. It should consist of a new independent linac-based FEL, operating in S- or L-band at energies between 4 and 16 MeV. Synchronized with the actual CLIO FEL and Optical Parametric Oscillators, it would a...

We have observed third-harmonic generation associated with intraband transitions in semiconductor quantum dots. The frequency tripling (12 mu m-->4 mu m) occurs in the valence band of InAs/GaAs self-assembled quantum dots. We show that the third-harmonic generation is enhanced due to the achievement of the double resonance condition between intraba...

The yeast microbiota present on the surface of grapes of two Vitis vinifera varieties, Pedro Ximénez and Tempranillo de Rioja, grown in the Montilla-Moriles region of southern Spain was identified. The changes between veraison and the physiological ripeness time during 3 years were monitored. Overall, the yeast microbiota isolated was of oxidative...

We have investigated the emission properties of InAs/GaAs self-assembled quantum dots in the mid-infrared. The emission relies on the intraband transitions in the valence band of the quantum dots. We first show that third-harmonic generation can be observed. The frequency tripling efficiency is enhanced by the resonances between the pump excitation...

Single color pump-probe and photon-echo experiments have been performed on the CO stretching mode of W(CO)(6) at about 1983cm(-1) in various liquids and solid environments. Combined with absorption data, the measured T-1 and T-2 times suggest the following conclusions: in all liquids studied, the IR absorption band is homogeneously broadened, where...

We have observed the saturation of intraband absorption in InAs/GaAs self-assembled quantum dots. The investigated n-doped self-assembled quantum dots exhibit an intraband absorption within the conduction band, which is peaked at an 8 μm wavelength. The saturation of the intraband absorption is achieved with an infrared pump delivered by a pulsed f...

The two-colour operation of a Free-Electron Laser (FEL) has been demonstrated with the “CLIO” infrared facility. A two section undulator allows the production of picosecond laser pulses at two different wavelengths and simultaneously, in a wavelength range from to , and with a wavelength separation of two colours of up to . The time overlap, betwee...