Search

This work presents and analyses the design of a multi-mode Low Noise Amplifier (LNA) dedicated to 2.4 GHz Wireless Sensor Network (WSN) applications. The proposed inductorless LNA, implemented in a 28 nm FDSOI CMOS technology, is based on a common-gate configuration imbedded with a common-source stage to boost the overall transconductance of the circuit. The LNA is specifically designed, and optimized, to address three modes of operation. The reconfiguration is performed through current tuning, combined with switching the back gate of the amplification transistors. The proposed implementation allows the figure of merit (FOM) to be maintained constant in the different modes of operation. In the low power mode, the LNA only consumes 350 uW. It achieves a voltage gain ( $\text{G}_{\mathrm {v}}$ ) of 16.8 dB and a noise figure (NF) of 6.6 dB. In the medium performance mode, the gain and the NF are respectively improved to 19.4 dB and 5.4 dB, the power consumption is 0.9 mW. In the high-performance mode, the gain is maximum, 22.9 dB, and the noise figure is minimum, 3.6 dB, for a power consumption of 2 mW. The linearity represented by the input referred third-order intercept point (IIP3) is constant, close to −16 dBm. The reported LNA occupies only 0.0015 mm2.

To demonstrate the capacity of Fully-Depleted Silicon-On-Insulator (FDSOI) technology, this paper presents two radio frequency designs taking benefit of the key advantages of the FDSOI. Specific process opportunities and body biasing are used to simultaneously reduce silicon area and improve radio frequency performance. First, a WiFi Power Amplifier (PA) fabricated in 28nm UTBB FDSOI process with 1.8v thick oxide MOS is presented. This PA exhibits a 23dBm Psat output power and l8dBm, 8% PAE under low distortion with a 3.7v power supply. This makes this PA suitable for 802.11ac WiFi standard requirements. Then an Ultra Low Power (ULP) inductorless Low Noise Amplifier (LNA) is presented using the same 28nm UTBB FDSOI technology. Based on a boosted common gate architecture, this LNA has been implemented reaching 16dB of voltage gain (G v ), 7.3dB Noise Figure (NF) for a total power consumption of only 300µW under 0.6v power supply. This structure points out the potential of back biasing to reduce the power consumption of more than 30% compared to classical CMOS design with similar RF performances.

International audience

This paper exploits the benefits of the body biasing on the design of an Ultra Low Power (ULP) inductorless Low Noise Amplifier (LNA) working at 2.4GHz. A comparison of two Fully-Depleted Silicon-On-Insulator (FDSOI) technologies: STMicroelectronics 28 nm UTBB FDSOI Technology and Global Foundry 22 nm FDX® Technology is proposed. The results in terms of Gain (S21), Noise Figure (Nf), Input Matching (S11) and power consumption of the LNA for the two technologies are presented. The simulated results shows the advantages of using the body biasing to lower significantly the power consumption of an Integrated Circuit (IC) block.

International audience

We present calculations of the free-free opacity of warm, solid-density aluminum at photon energies between the plasma frequency at 15 eV and the L-edge at 73 eV, using both density functional theory combined with molecular dynamics and a semi-analytical model in the RPA framework which includes exciton contributions. As both the ion and electron temperature is increased from room temperature to 10 eV, we see a marked increase in the opacity. The effect is less pronounced if only the electron temperature is allowed to increase, while the lattice remains at room temperature. The physical significance of these increases is discussed in terms of intense light-matter interactions on both femtosecond and picosecond time scales. © 2009 Elsevier B.V. All rights reserved.

In this paper, a system level analysis for channel aware receiver is described. Based on a real-time estimation of the received power, this study proposes an optimization of the sensitivity ranges for such adaptative receiver. From the performances vs power consumption trade-off and a statistical analysis of the received power, smart threshold optimization leads to a significant increase of Wireless Sensor Network (WSN) battery lifetime by factors up to 5 or 6.

International audience

International audience; Today, light fields of controlled and measured waveform can be used to guide electron motion in atoms and molecules with attosecond precision. Here, we demonstrate attosecond control of collective electron motion in plasmas driven by extreme intensity ($\approx$10$^{18}$ W cm$^{−2}$) light fields. Controlled few-cycle near-infrared waves are tightly focused at the interface between vacuum and a solid-density plasma, where they launch and guide subcycle motion of electrons from the plasma with characteristic energies in the multi-kiloelectronvolt range--two orders of magnitude more than has been achieved so far in atoms and molecules. The basic spectroscopy of the coherent extreme ultraviolet radiation emerging from the light-plasma interaction allows us to probe this collective motion of charge with sub-200 as resolution. This is an important step towards attosecond control of charge dynamics in laser-driven plasma experiments.

Monitoring of electrocorticography signals using multi-electrode array creates new opportunities for neural prosthetic applications. In this paper, we present a 32-channel recording ASIC that provides low-noise amplification and analog filtering. It also includes a 12-bit analog-to-digital conversion function, and offers programmable output rates through a serial peripheralinterface (SPI). The targeted application is a remote-powered wireless implantable ECoG recording system. Each recording channel has a measured 0.7 $\mu {\rm V_{\rm rms}}$ input-referred noise on a [0.5–300 Hz] bandwidth. The device was fabricated in a 0.35 $\mu{\rm m}$ complementary metal–oxide–semiconductor process for a total die area of 86 ${\hbox {mm}} ^{2}$ with an analog power consumption limited to 134 $\mu {\rm W}$ per channel.

The objective of the Apollon 10 PW project is the generation of 10 PW peak power pulses of 15 fs at $1~\text{shot}~\text{min}^{-1}$ . In this paper a brief update on the current status of the Apollon project is presented, followed by a more detailed presentation of our experimental and theoretical investigations of the temporal characteristics of the laser. More specifically the design considerations as well as the technological and physical limitations to achieve the intended pulse duration and contrast are discussed.

The interaction of high-intensity laser pulses with matter releases instantaneously ultra-large currents of highly energetic electrons, leading to the generation of highly-transient, large-amplitude electric and magnetic fields. We report results of recent experiment in which such phenomena have been studied by using proton probing techniques able to provide maps of the electrostatic fields with high spatial and temporal resolution. The dynamics of ponderomotive channelling in underdense plasmas have been studied with this technique, as also the process of Debye sheath formation and MeV ion front expansion at the rear of laser-irradiated thin metallic foils.

International audience; We present a high-contrast 10-fs Front-End for Ti:sapphire PW-lasers within the Apollon-10PW project. This injector uses OPCPA pumped at 100 Hz by Yb-based CPA chain. Combination of OPCPA and XPW permits a >10 12 contrast ratio.

Intense lasers of femtosecond pulse duration are known to be drivers for intense electron and ion beams. Those beams, generated at laser intensities exceeding 10 19 W/cm 2 , are known to have unique characteristics and are therefore a subject of intense research world wide. Recently, the parameters of laser driven ion beams have been measured using new methods and it has been demonstrated, that beam patterns on a nanometer scale can be generated and propagated over long distances. We report on recent results and prospects for future application with special respect to further laser developments.

L’artisan est tres souvent entraine, par ses clients, dans des processus de negociation, surtout sur les prix. Dans toute negociation, il y a des strategies, des techniques, des tactiques, des phases, des procedures, autrement dit des elements tres « mecaniques » qui n’ont pas grand-chose a voir avec le comportement et / ou la personnalite des negociateurs.Cet article decrit brievement une des cles de succes de toute negociation, a savoir sa preparation.

The ionization and recombination dynamics of transient aluminum plasmas was measured using point projection K-shell absorption spectroscopy. An aluminum plasma was produced with a subpicosecond beam of the 100-TW laser at the LULI facility and probed at different times with a picosecond X-ray backlighter created with a synchronized subpicosecond laser beam. Fourier-Domain-Interferometry (FDI) was used to measure the electron temperature at the peak of the heating laser pulse. Absorption X-ray spectra at early times are characteristic of a dense and rather homogeneous plasma, with limited longitudinal gradients as shown by hydrodynamic simulations. The shift of the Al K-edge was measured in the cold dense plasma located at the edge of the heated plasma. From the 1s–2p absorption spectra, the average ionization was measured as a function of time and was also modeled with a collisional-radiative atomic physics code coupled with hydrodynamic simulations.

We present a technique for simultaneous focusing and energy selection of high-current, mega–electron volt proton beams with the use of radial, transient electric fields (10 7 to 10 10 volts per meter) triggered on the inner walls of a hollow microcylinder by an intense subpicosecond laser pulse. Because of the transient nature of the focusing fields, the proposed method allows selection of a desired range out of the spectrum of the polyenergetic proton beam. This technique addresses current drawbacks of laser-accelerated proton beams, such as their broad spectrum and divergence at the source.

Intense beams of protons and heavy ions have been observed in ultra-intense laser-solid interaction experiments. Thereby, a considerable fraction of the laser energy is transferred to collimated beams of energetic ions (e.g. up to 50 MeV protons; 100 MeV fluorine), which makes these beams highly interesting for various applications. Experimental results indicate very short pulse duration and an excellent beam quality, leading to beam intensities in the TW range. To characterize the beam quality and its dependence on laser parameters and target conditions we performed experiments at several high-power laser systems. We found a strong dependence on the target rear surface conditions allowing to tailor the ion beam by an appropriate target design. We also succeeded in the generation of heavy ion beams by suppressing the proton amount at the target surface.

The acceleration of ions by ultra-intense lasers has attracted great attention due to the unique properties and the unmatched intensities of the ion beams. In the early days the prospects for applications were already studied, and first experiments have identified some of the areas where laser accelerated ions can contribute to the ongoing inertial confinement fusion (ICF) research. In addition to the idea of laser driven proton fast ignition (PFI) and its use as a novel diagnostic tool for radiography the strong dependence on the electron transport in the target was found to be helpful in investigating the energy transport by electrons in fast ignitor scenarios. More recently an additional idea has been presented to use laser accelerated ion beams as the next generation ion sources, and taking advantage of the luminosity of the beams, to develop a test bed for heavy ion beam driven inertial confinement fusion physics. We review our recent experiments and simulations relevant to ICF research presenting a possible scenario for PFI as well as the prospects for next generation ion sources.

This paper reports the results of a series of experiments on laser generated ions using the 100 TW laser at the ‘Laboratiore pour l’Utilisation des Lasers Intenses (LULI)’ at the Ecole Polythechnique in Palaiseau, France, and the 30 TW ‘Trident’ facility at Los Alamos National Laboratories in New Mexico, USA. It shows the importance of the ‘Target Normal Sheath Acceleration’ process (TNSA) for short pulse laser generated ion beams and its connection to the influence of target properties on the ion beam quality. It is shown that TNSA-generated protons form an ion beam with superior beam quality, following versatile spatial beam shaping approaches. These insights are set into perspective for a fast ignitor scenario based on short pulse laser generated protons.

The laminarity of high current multi-MeV proton beams produced by irradiating thin metallic foils with ultra-intense lasers has been measured. For proton energies >10 MeV, the transverse and longitudinal emittance are, respectively, −4 eV s, i.e. at least 100-fold and may be as much as 10 4 -fold better than conventional accelerators beams. The ion beam source size is measured to be 10 MeV. Magnetic stripping of the co-moving electrons out of the beam after a few cm of debunching is not observed to induce emittance growth.

La vente et la negociation sont restees tres longtemps des concepts differencies; vendre etait directement lie a une transaction commerciale alors que la negociation restait l’apanage, soit des diplomates, soit des managers pour les relations sociales. Depuis plusieurs annees nous constatons, dans la pratique des affaires, une confusion des deux fonctions.

We report on measurements of source sizes and charge state distributions of ions accelerated from thin foils irradiated by ultrashort (100–300 fs) high-intensity (1-6×1019 W/cm2) laser pulses. The source sizes of proton and carbon ion beams originating from hydrocarbon contaminants on the surfaces of 5 μm thick aluminum foils were investigated using the knife-edge method. For low-energy protons and low-carbon charge states, the source area was found to exceed the focal spot area by a factor of 104. For the determination of charge state distributions, sandwich targets consisting of a 25 μm thick tungsten layer, a 2-nm thin beryllium layer, and again a tungsten layer whose thickness was varied were used. These targets were resistively heated to remove the light surface contaminants. Peaked energy spectra of oxygen and argon ions corresponding to the equilibrium distribution after propagation through matter were observed.

Recent experimental results on ion beams produced in high-intensity laser–solid interactions indicate the presence of very intense electric fields in the target. This suggests the possibility of efficiently heating a solid material by means of the fast electrons created during the laser–solid interactions and trapped in the target, rather than by the laser photons themselves. We tested this mechanism by irradiating very small cubic aluminum targets with the LULI 100-TW, 300-fs laser at 1.06-μm wavelength. X-ray spectra were measured with an ultra-fast streak camera, coupled to a conical Bragg crystal, providing spectra in the 1.5-keV range with high temporal and spectral resolution. The results indicate the creation of a hot plasma, but a very low coupling between the rapid electrons and the solid. A tentative explanation, in agreement with other experimental results and with preliminary particle-in-cell (PIC) simulations, points out the fatal role of the laser prepulse.

We present a high-contrast 10-fs Front-End for Ti:sapphire PW-lasers within the Apollon-10PW project. This injector uses OPCPA pumped at 100Hz by Yb-based CPA chain. Combination of OPCPA and XPW permits a >1012 contrast ratio.

International audience; Applications using multi-PW lasers necessitate high temporal pulse quality with a tremendous contrast ratio (CR). The first crucial prerequisite to achieve multi-PW peak power is the generation of ultrashort pulses with good spectral phase quality. Second, to avoid any deleterious pre-ionization effect on targets, nanosecond contrast better than 10$^{12}$ is also targeted. In the framework of the Apollon 10 PW French laser program, we present a high-contrast 10 fs front-end design study to inject highly energetic Ti:sapphire PW lasers. The CR has been measured and analyzed in different time ranges highlighting the different major contributions for each scale.

International audience

International audience

International audience

An experimental and numerical analysis of the ionization dynamics of a freely expanding nanosecond laser-produced plasma is given. Point-projection X-ray absorption spectroscopy with picosecond time-resolution is used to provide a spatio-temporal mapping of the ion distribution. The average ionization state, calculated as a function of time and distance to the target, is used to benchmark hydrodynamics and atomic physics codes. A comparison with several codes has been performed, showing that a full description of radiation transport, 2-D effects and detailed, time-dependent, atomic physics is necessary in order to explain the experimental results.

Monomode guiding over 100 Rayleigh lengths (10 cm) of high intensity ultrashort laser pulses ( ${10}^{16}\mathrm{W}/{\mathrm{cm}}^{2}$, 120 fs) has been demonstrated in hollow dielectric capillary tubes (45--70 \ensuremath{\mu}m internal diameter) without inner wall damage. Analytical predictions for coupling conditions and damping length are confirmed experimentally for tubes under vacuum. With 5 to 40 mbar of He gas in the tube, when laser ionization occurs the energy and duration of the transmitted pulse decrease while its spectrum is broadened.

We describe an experiment on isochoric heating of matter by intense laser-accelerated protons. The experiment was performed using the LULI 100 TW facility with 15-20 J on target energy and > 10 19 W.cm -2 maximum focused intensity. Focusing the laser on a 10 micron thick Au foil, we accelerated forward a laminar proton beam with a maximum energy of 16 MeV. This proton beam irradiated and heated a secondary target positioned after a variable vacuum gap. The heating was diagnosed by ID and 2D time-resolved measurements of the optical self-emission of the heated target rear-surface. Detailed results as a function of the Z and the thickness of the secondary target as well as analysis, including a full modelling of the target heating with a 2D hydro-code (DUED) coupled to a proton energy deposition code, were obtained. We have also studied the efficiency of heating as a function of the primary target topology, i.e. either flat, which results in a diverging proton beam, or curved, which has the ability of focusing partly the proton beam.

A double foil assembly is shown to be effective in tailoring the maximum energy produced by a laser-accelerated proton beam. The measurements compare favorably with adiabatic expansion simulations, and particle-in-cell simulations. The arrangement proposed here offers for some applications a simple and passive way to utilize simultaneously highest irradiance lasers that have best laser-to-ion conversion efficiency while avoiding the production of undesired high-energy ions.