Good performances in tele-surgery procedures is achieved when the surgeon acts and feels as if he were holding directly in his hands the surgical instruments interacting with the patient. To reach this goal, a high fidelity haptic device was recently developed at CEA LIST. As the development of such an input device calls for a precise understanding of the application requirements, we first introduce in this paper Minimally Invasive Surgery problematics and associated design guidelines. Then we focus on dimensioning and optimisation of input device performances allowing high quality remote handling. Finally, we present master arm first and second generation prototypes and their performances.

In this article, we present a new wearable haptic interface developed at CEA-LIST for precise finger interactions within virtual reality applications in large environments. The hand movements are tracked using a stereoscopic visual tracking system, allowing large movements in free space. Moreover, the device integrates two three degrees of freedom with force feedback robots associated with index and thumb fingers, allowing virtual objects fine manipulation. Finally, a two degrees of freedom tactile actuator is integrated under the pulp of each fingertip in order to improve the high frequency response of the haptic interface and to provide information on the texture and the shape of the virtual objects manipulated.

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Photoelectron Angular Distributions (PADs) resulting from 800 nm and 1300 nm strong field ionization of impulsively aligned CF3I molecules were analyzed using time-dependent density functional theory (TDDFT). The normalized difference between the PADs for aligned and anti-aligned molecules displays large modulations in the high-energy re-collision plateau that are assigned to the diffraction of back-scattered photoelectrons. The TDDFT calculations reveal that, in spite of their 2.6 eV energy difference, ionization from the HOMO-1 orbital contributes to the diffraction pattern on the same footing as ionization from the doubly degenerate HOMO orbital.Following structural changes within single molecules on their natural time and length scales is one of the great challenges in ultrafast molecular physics. Large efforts are currently devoted to the development of techniques for the direct imaging of nuclear motion with atomic resolution. Diffractive imaging methods using ultrashort X-ray pulses available at Free Electron Lasers [1, 2], or using ultrashort electron pulses [3][4][5], have the potential to record structural information with the spatiotemporal resolution required for obtaining "molecular movies" [3,[5][6][7]. In both approaches however, realizing single molecule imaging with sub-10 fs temporal resolution has proven challenging [8,9], since the required synchronization between the visible/ultra-violet laser pulses initiating the molecular dynamics of interest and the Xray/UED probe is difficult to achieve.Fully laser-based molecular self-imaging techniques using strong field ionization by an intense infrared (IR) laser pulse are an alternative and promising route towards the imaging of (time-dependent) molecular structures in the gas phase [10]. In particular, Laser-Induced Electron Diffraction (LIED) [11][12][13][14], where the ionization of a molecule by a strong IR laser field leads to the creation of a photoelectron wavepacket that is accelerated by the laser field to induce a recollision with the parent molecular ion, has already demonstrated fewfemtosecond and sub-Ångström resolution [15][16][17]. The time resolution in LIED is given by the optical cycle of the driving laser field [15,17] and can reach the subfemtosecond timescale, whereas high spatial resolution is possible due to the high kinetic energy of the re-colliding photoelectron, which determines its De Broglie wavelength and can reach values of 0.1Å when using midinfrared laser fields.Retrieval of the molecular structure from an LIED experiment is often done in the framework of the Quan-titative Rescattering Theory (QRT) [13,18,19], which usually assumes that (i) the ionization takes place from the Highest Occupied Molecular Orbital (HOMO) and that (ii) the initial shape of the electron wavepacket is lost during its propagation in the oscillatory laser field, so that the re-colliding electron wavepacket can be approximated by a plane wave. Both of these assumptions may be questioned. Strong field ionization, in particular of polyatomic mol...

We investigate the pulse partitioning of a 6.3-mJ, 450-fs pulse at 1030 nm to produce plasma channels. At such moderate energies, splitting the energy into several subpulses reduces the ionization efficiency and thus does not extend the plasma lifetime. We numerically show that when sufficient energy to produce multifilamentation is available, splitting the pulse temporally in a pulse train increases the gas temperature compared to a filament bundle of the same energy. This could improve the mean free path of the free electrons, therefore enhancing the efficiency of discharge triggering.

We measured the chemical composition and the size distribution of aerosols generated by femtosecond-Terawatt laser pulses in the atmosphere using an aerosol mass spectrometer (AMS). We show that nitric acid condenses in the form of ammonium nitrate, and that oxidized volatile organics also contribute to particle growth. These two components account for two thirds and one third, respectively, of the dry laser-condensed mass. They appear in two different modes centred at 380 nm and 150 nm. The number concentration of particles between 25 and 300 nm increases by a factor of 15. Pre-existing water droplets strongly increase the oxidative properties of the laser-activated atmosphere, substantially enhancing the condensation of organics under laser illumination.

In this paper, we present a new six degrees of freedom haptic device developed at CEA-LIST for desktop applications emphasizing quick and precise manipulation. This device relies on a light parallel architecture connecting the base of the robot to the mobile platform manipulated by the user. It is dimensioned and optimized to fit design requirements associated with Computer Aided Design or virtual sculpting. The design methodology relies on a geometric and static optimization which takes into account technological constraints associated with the main off the shelf components. The control scheme of this device is also described. Finally, feedback obtained from first integration tests are presented.

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