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International audience; The study of complex reactive flows met in aeronautical engines is an experimental challenge that requires the development of noninvasive and precise measurement techniques. Coherent anti-Stokes Raman scattering (CARS) is a standard spectroscopic technique used for temperature measurements, which provides unmatched reliability and accuracy at high repetition rate thanks to its recent adaptation to femtosecond temporal regime. This paper reports the first demonstration of hybrid fs/ps-CARS thermometry in a representative aeronautical combustor (ONERA MICADO test bench, Reynolds number ≈105). Single-shot N2 CARS spectra have been recorded at 1 kHz, allowing temperature follow up, statistical and frequency (0.1–500 Hz) analysis of CH4/air flame at 0.34-MPa total pressure. The achieved results demonstrate the ability of the technique to be applied in representative engines conditions and its maturity for semi-industrial applications.

International audience; We report on the current design and preliminary developments of the airborne Lidar Emitter and Multi-species greenhouse gases Observation iNstrument (LEMON), which is aiming at probing H2O and its isotope HDO at 1982 nm, CO2 at 2051 nm, and potentially CH4 at 2290 nm, with the Differential Absorption Lidar method (DIAL). The infrared emitter is based on the combination of two Nested Cavity OPOs (NesCOPOs) with a single optical parametric amplifier (OPA) line for high-energy pulse generation. This configuration is enabled by the use of high-aperture periodically poled KTP crystals (PPKTP), which provide efficient amplification in the spectral range of interest around 2 μm with slight temperature adjustments. The parametric stages are pumped with a Nd:YAG laser providing 200 mJ nanosecond double pulses at 75 Hz. According to parametric conversion simulations supported by current laboratory experiments, output energies in the 40 - 50 mJ range are expected in the extracted signal beam whilst maintaining a good beam quality (M2 < 2). The ruler for all the optical frequencies involved in the system is planned to be provided by a GPS referenced frequency comb with large mode spacing (1 GHz) against which the emitter output pulses can be heterodyned. The frequency precision measurement is expected to be better than 200 kHz for the optical frequencies of interest. The presentation will give an overview of the key elements of design and of preliminary experimental characterizations of sub-systems building blocks.

International audience; The Lidar Emitter and Multi-species greenhouse gases Observation iNstrument (LEMON) is a novel Differential Absorption Lidar (DIAL) sensor concept for greenhouse gases and water vapor measurements from space.1,2 It is based on a versatile transmitter allowing for addressing various absorption lines of different molecules. This highly flexible emitter design requires a universal frequency referencing scheme. Here we present a concept employing a 1 GHz frequency comb, which allows the absolute referencing over a spectral range from 0.95 μm to 1.15 μm. By using an intermediate frequency doubling stage, this allows for DIAL measurements on CO2, H2O/HDO, and CH4 in the 2 μm range. Absolute referencing is obtained by using a GPS disciplined oscillator as the common time base for frequency measurements. The concept of the LEMON Frequency Reference UnIT (FRUIT) is designed to match the requirements of the vibration loads associated with airborne operation to allow implementation on the airborne demonstrator for LEMON. In addition, the requirements for a future space development are considered in the design. For example, radiation critical items have been identified and radiation tested within the project and a compact wavemeter design has been implemented.

International audience; Hybrid fs/ps CARS thermometry has been performed in an aeronautical combustor during turbulent CH4/air combustion (3.5 bar). Single shot N2 CARS spectra have been recorded at 1 kHz, allowing statistical and frequency ([0.1-500] Hz) analysis.; Une campagne de thermométrie par spectroscopie CARS en régime hybride fs/ps a été réalisée dans une flamme turbulente CH4/air (3.5 bar) au sein d'une chambre de combustion aéronautique représentative. des spectres de N2 ont été acquis en tir unique à la cadence de 1 kHz permettant une analyse statistique et fréquentielle (bande [0.1-500] Hz).

We present the design of a differential absorption LIDAR targeting HDO/H216O isotopic ratio measurement with high vertical resolution. This approach is enabled by infrared water vapor spectroscopy and recent high power multi-species parametric emitter developments.

International audience; We report measurements of absolute frequencies of various polyatomic species around 10 μm, at level of accuracies ranging from 10 Hz to 10 kHz, using a widely tuneable SI-traceable optical frequency comb-stabilized quantum cascade laser.

International audience; Non-invasive and accurate measurements are essential to study the reactive flows in aeronautical engines. This paper reports the results of a unique measurement campaign providing the temperature flowfield in a large scale facility turbomachine test rig using spontaneous rotational Raman scattering technique. Different planes of interest and operating conditions are probed, showing good agreement with thermocouple measurements. Fast temperature variations (>7.7 kHz) could be probed thanks to synchronization of the laser pulse with the rotor clock. Results outline the performance of in situ Raman technique to investigate steady and unsteady flows in turbine's conditions.

International audience; There is an increasing demand for precise molecular spectroscopy, in particular in the mid-infrared fingerprint window that hosts a considerable number of vibrational signatures, whether it be for modeling our atmosphere, interpreting astrophysical spectra or testing fundamental physics. We present a high-resolution mid-infrared spectrometer traceable to primary frequency standards. It combines a widely tunable ultra-narrow Quantum Cascade Laser (QCL), an optical frequency comb and a compact multipass cell. The QCL frequency is stabilized onto a comb controlled with a remote near-infrared ultra-stable laser, transferred through a fiber link. The resulting QCL frequency stability is below 10-15 from 0.1 to 10s and its frequency uncertainty of 4×10-14 is given by the remote frequency standards. Continuous tuning over ~400 MHz is reported. We use the apparatus to perform saturated absorption spectroscopy of methanol in the low-pressure multipass cell and demonstrate a statistical uncertainty at the kHz level on transition center frequencies, confirming its potential for driving the next generation technology required for precise spectroscopic measurements.

International audience; We present a brief review of our progress towards measuring parity violation in heavy-metal chiral complexes using mid-infrared Ramsey interferometry. We discuss our progress addressing the main challenges, including the development of buffer-gas sources of slow, cold polyatomic molecules, and the frequency-stabilisation of quantum cascade lasers calibrated using primary frequency standards. We report investigations on achiral test species of which promising chiral derivatives have been synthesized.

DIfferential Absorption Lidars (DIAL) can be powerful tools for remote detection of various gaseous species. We report here on the instruments that we have recently developed, based on specific optical sources, for industrial safety applications, as well as for defense applications.

International audience; La combustion est un sujet d’intérêt pour une large variété de domaines d’applications civils ou militaires. Comprendre les phénomènes physico-chimiques à l’oeuvre dans ces milieux complexes, et les décrire à l’aide de modèles éprouvés, sont des enjeux majeurs qui requièrent des mesures fiables et quantitatives. La spectroscopie par diffusion Raman anti-Stokes cohérente (DRASC ou CARS en anglais) a démontré des performances inégalées pour la mesure de température. Cette technique a été implémentée avec de nombreuses architectures laser, et appliquée avec succès à un large éventail de milieux.

We are stabilizing the frequency of a mid-infrared quantum cascade lasers (QCLs) to an optical frequency comb itself stabilized to an ultra-stable near-infrared reference signal at $\pmb{1.5\mu} \mathbf{m}$ transferred from SYRTE to LPL using an optical link. The reference stability is copied to the QCL and we benefit from the traceability to the primary standards of SYRTE. The stabilized QCL can be scanned by scanning the near-IR reference with an electro-optic modulator. We use this ultrastable spectrometer to carry out saturated absorption spectroscopy of methanol. A detailed analysis of the frequency measurement uncertainty will be presented.

We present a frequency comb-assisted experimental setup which enables us to both coherently transfer the stability and accuracy of a remote near-infrared (NIR) ultrastable laser to a mid-infrared (MIR) quantum cascade laser (QCL), and widely tune the QCL frequency for spectroscopic applications. The QCL is stabilized at the level of 2×10−15 from 1 to 100 s, with an accuracy of 10−14 after 100 s. The achievable frequency tuning paves the way for high-resolution saturated absorption spectroscopy of molecular transitions, in particular in spectral regions that were previously inaccessible with standard stabilized MIR lasers. Preliminary results show a sensitivity at the kHz level on transition center frequencies.

The sensitivity achieved by large ring-laser gyroscopes will make it possible to detect faint relativistic effects related to the rotation of the Earth's mass. This task requires a strict control of the ring cavity geometry (shape and orientation), which can be performed by a novel network of portable heterodyne interferometers, capable of measuring the absolute distance betweeen two retro-reflectors with a nominal accuracy better than 1nm. First steps have been taken towards the realization of this device and a starting prototype of distance gauge is under development and test.

Large frame ring laser gyros performances are ultimately limited by the instabilities of their geometrical parameters. We present the experimental activity on the GP2 ring laser gyro. GP2 is a ring laser gyro devoted to develop advanced stabilization techniques of the ring cavity geometrical scale-factor. A method based on optical interferometry has been developed for canceling the deformations of the resonator. The method is based on the measurement and stabilization of the absolute length of the cavity perimeter and of the resonators formed by the opposite cavity mirrors. The optical frequency reference in the experiment is an iodine-stabilized He-Ne laser, with a relative frequency stability of 10−11. The measurement of the absolute length of the two resonators has been demonstrated up to now on a test bench. We discuss the experimental results on GP2: the present performances as a ring laser gyro and the stabilization scheme to be implemented in the near future.

Ultra-sensitive ring laser gyroscopes are regarded as potential detectors of the general relativistic frame-dragging effect due to the rotation of the Earth. Our project for this goal is called GINGER (gyroscopes in general relativity), and consists of a ground-based triaxial array of ring lasers aimed at measuring the rotation rate of the Earth with an accuracy of . Such an ambitious goal is now within reach, as large-area ring lasers are very close to the required sensitivity and stability. However, demanding constraints on the geometrical stability of the optical path of the laser inside the ring cavity are required. Thus, we have begun a detailed study of the geometry of an optical cavity in order to find a control strategy for its geometry that could meet the specifications of the GINGER project. As the cavity perimeter has a stationary point for the square configuration, we identify a set of transformations on the mirror positions that allows us to adjust the laser beam steering to the shape of a square. We show that the geometrical stability of a square cavity strongly increases by implementing a suitable system to measure the mirror distances, and that the geometry stabilization can be achieved by measuring the absolute lengths of the two diagonals and the perimeter of the ring.

He-Ne ring lasers are, actually, the most sensitive devices for inertial rotation measurements. Depending on their linear dimensions, they find applications in different fields: from inertial navigation to structural engineering, from metrology to geophysics and fundamental physics. Here we report the recent progresses toward the development of GINGER- Gyroscopes IN GEneral Relativity, a triaxial ultra-sensitive ring laser gyroscope whose primary target is a ground measurement the Lense-Thirring effect, a small shift of the Earth rotation rate foreseen by Einstein's General Relativity. This target implies a measurement of the Earth rotation rate with a sensitivity better than one part over 10 10 and so requires a high level of stability and accuracy of the laser array and of the gyroscope stability. The main part of the research activity presented in this paper involves, then, a strict control of the systematic errors related to the fluctuation of the optical cavity geometry and of the laser parameters.

After reviewing the importance of light as a probe for testing the structure of space-time, we describe the GINGER project. GINGER will be a three-dimensional array of large size ring-lasers able to measure the de Sitter and Lense-Thirring effects. The instrument will be located at the underground laboratory of GranSasso, in Italy. We describe the preliminary actions and measurements already under way and present the full road map to GINGER. The intermediate apparatuses GP2 and GINGERino are described. GINGER is expected to be fully operating in few years., 11 pages, in Comptes Rendus Physique, Special Issue "The Sagnac effect: 100 years later"

GINGER is a proposed tridimensional array of laser gyroscopes with the aim of measuring the Lense-Thirring effect, predicted by the General Relativity theory, in a terrestrial laboratory environment. We discuss the required accuracy, the methods to achieve it, and the preliminary experimental work in this direction., Submitted to International Journal Laser Physics, 9 pages, 5 figure

The sensitivity achieved by large laser gyroscopes opens the perspective of observing in a ground laboratories very thin relativistic effect related to the Earth rotating mass (gravitomagnetic effect or Lense-Thirring effect). The required accuracy asks for a strict control of the ring cavity geometry. Here we present a control procedure that can be applied in order to solve this task.

GINGER (Gyroscopes IN GEneral Relativity) is a proposal for measuring in a ground-based laboratory the Lense-Thirring effect, known also as inertial frame dragging, that is predicted by General Relativity, and is induced by the rotation of a massive source. GINGER will consist in an array of at least three square ring lasers, mutually orthogonal, with about 6-10 m side, and located in a deep underground site, possibly the INFN - National Laboratories of Gran Sasso. The tri-axial design will provide a complete estimation of the laboratory frame angular velocity, to be compared with the Earths rotation estimate provided by IERS with respect the fixed stars frame. Large-size ring lasers have already reached a very high sensitivity, allowing for relevant geodetic measurements. The accuracy required for Lense-Thirring effect measurement is higher than 10-14 rad/s and therefore Earth angular velocity must be measured within one part in 10-9. A 3.6 m side, square ring laser, called GINGERino, has been recently installed inside the Gran Sasso underground laboratories in order to qualify the site for a future installation of GINGER. We discuss the current status of the experimental work, and in particular of the GINGERino prototype.

BACKGROUND: Airway inflammation in asthma involves both large and small airways, and the combination of inhaled corticosteroids (ICS) and long acting beta-2 agonists (LABA) is the mainstay of therapy. Available inhaled combinations differ in terms of drug delivery to the lung and the ability to reach small airways. Aim: To evaluate whether treatment with an extra-fine inhaled combination provides additional effects vs a nonextra-fine combination on airway function. METHODS: After a 1- to 4-week run-in period, patients with asthma were randomized to a double blind, double dummy, 12-week treatment with either extra-fine beclomethasone/formoterol (BDP/F) 400/24 microg daily or fluticasone propionate/salmeterol (FP/S) 500/100 microg daily. Methacholine (Mch) bronchoprovocation challenge and single breath nitrogen (sbN2) test were performed. RESULTS: Thirty patients with asthma (15 men), mean age 43, mean forced expiratory volume in the first second (FEV(1)) 71.4% of predicted, were included. A significant increase (P < 0.01) versus baseline was observed in predose FEV(1) in both BDP/F and FP/S groups (0.37 +/- 0.13 l and 0.36 +/- 0.12 l, respectively). PD(20)FEV(1) Mch improved significantly from 90.42 (+/-30.08) microg to 432.41 (+/-122.71) microg in the BDP/F group (P = 0.01) but not in the FP/S group. A trend toward improvement vs baseline was observed for BDP/F in closing capacity (CC), whereas no differences were recorded in other sbN(2) test parameters. CONCLUSION: The findings of this pilot study suggest that an extra-fine inhaled combination for the treatment of asthma has beneficial effects on both large and small airways function as expressed by Mch and sbN(2) tests.

We present the experimental test of a method for controlling the absolute length of the diagonals of square ring laser gyroscopes. The purpose is to actively stabilize the ring cavity geometry and to enhance the rotation sensor stability in order to reach the requirements for the detection of the relativistic Lense-Thirring effect with a ground-based array of optical gyroscopes. The test apparatus consists of two optical cavities 1.32 m in length, reproducing the features of the ring cavity diagonal resonators of large frame He-Ne ring laser gyroscopes. The proposed measurement technique is based on the use of a single diode laser, injection locked to a frequency stabilized He-Ne/Iodine frequency standard, and a single electro-optic modulator. The laser is modulated with a combination of three frequencies allowing to lock the two cavities to the same resonance frequency and, at the same time, to determine the cavity Free Spectral Range (FSR). We obtain a stable lock of the two cavities to the same optical frequency reference, providing a length stabilization at the level of 1 part in $10^{11}$, and the determination of the two FSRs with a relative precision of 0.2 ppm. This is equivalent to an error of 500 nm on the absolute length difference between the two cavities.

In recent years the development of large ring laser gyroscopes gave birth to a new discipline: the rotational seismology. This field of study is rapidly expanding and many areas of geophysics are or can be involved, from geodesy to seismology to the monitoring of critical structures. New rotational sensors based on optical interferometry and Sagnac effect has been developed in the last two decades. These sensors are called ring laser gyroscopes (RLG) and are now able to cover the range of rotations of seismological interest i.e. from 10−2 to 10−9 rad/sec. A measure of rotations in seismology is of fundamental interest for several reasons: Quantitative seismology requires a measure of all the six degrees of freedom that characterize a rigid body’s motion. Standard seismological observations are contaminated by rotations that produce a bias in the estimate of ground translation. Rotational observables provide important informations about the elastic properties of the subsoil. The extension of rotational observations to exploration seismology can improve resolution and accuracy of subsurface imaging.

Accurate molecular spectroscopy in the mid-infrared (mid-IR) region allows precision measurements with applications in fundamental physics. We present our on-going work towards measuring absolute vibrational frequencies of various polyatomic species — in particular methanol — around 10 μm, at an unprecedented level of accuracy, using a both ultra-stable and widely tuneable near-infrared frequency comb. We have recently been able to lock mid-IR radiation to a frequency comb stabilized to a 1.54 μm near-IR reference [1, 2]. This reference, generated at the French national metrology institute (LNE-SYRTE), is monitored against atomic frequency standards [3] and transferred to LPL via a 43-km long optical fibre [4] (see Fig. 1). This provides the ultimate frequency accuracy (potentially the 3x10−16 of the Cs fountain clock) and stability (∼10−15 after 1s of integration).

Active control of the geometrical parameters of large ring-lasers arrays is a challenging task, requiring the development of an accurate length monitoring system acting on the edges of these devices. The proposed solution is based on what was outlined by NASA JPL for its discontinued Space Interferometric Mission (SIM). It will be made up of a network of compact laser heterodyne interferometers, working together to keep the geometrical frame constantly well known (and fixed) to nanometer accuracy. We took the first steps towards the realization of this device by focusing on its fundamental element, i.e. the compact heterodyne laser interferometer. A starting simplified prototype has been conceived and is now under development. Its preliminary design will let us to evaluate parts behavior, alignment issues and links between single components and overall gauge performances. Concerned distance is investigated by means of a reference and a measurement beam, obtained by spatial splitting of the laser source. The phase shift between two heterodyne beatings will provide a reliable signal for precise monitoring of a linear distance.

Il contributo esamina la portata che il principio di proporzionalità ed il criterio ermeneutico-argomentativo di ragionevolezza assumono nella Proposta di Regolamento del diritto comune europeo della vendita. L’analisi assume preminente interesse, poiché il provvedimento, pur non essendo stato approvato, rappresenta un modello innovativo di regolamentazione uniforme, ispirato al principio di “giustizia contrattuale”.

Il capitolo tratta diffusamente della disciplina della società in nome collettivo

Il capitolo tratta diffusamente della disciplina della società in accomandita semplice e della società semplice

Il contributo valuta l'opera di recepimento della direttiva 2008/122/CE del 14 gennaio 2009 sulla tutela dei consumatori per quanto riguarda taluni aspetti dei contratti di multiproprietà, dei contratti relativi ai prodotti per le vacanze di lungo termine e dei contratti di rivendita e di scambio, ponendo in luce i profili di novità di tale disciplina rispetto a quella compendiata dalla legislazione precedente.

Lo studio analizza i nuovi modelli giuridici differenziati - Circuiti nazionali d'eccelenza, sistemi turistici locali, distretti turistici - per l'intervento pubblico a sostegno dello sviluppo e della competitività del turismo, basati sulla collaborazione tra imprese di settor e soggetti pubblici responsabili del governo del territorio.