Gerard Mourou

Bio: Gerard Mourou is an academic researcher from École Polytechnique. The author has contributed to research in topics: Laser & Ultrashort pulse. The author has an hindex of 82, co-authored 653 publications receiving 34147 citations. Previous affiliations of Gerard Mourou include University of Michigan & San Diego State University.

Long-range, high-resolution laser radar

Abstract: A high energy, chirped pulse laser was used to demonstrate long range, high resolution radar. A broadband nanosecond chirped pulse propagated to a target, and upon compression sub-millimeter surface resolution was obtained. This technique avoided the nonlinear effects in air that were seen when a picosecond pulse propagated to the target.

Femtosecond laser: cavitation bubbles analysed by confocal microscopy

Abstract: Purpose: When a femtosecond laser beam causes photodisruption, a cavitation bubble is produced. Many laser shots may be placed close together, and the induced cavitation bubbles coalesce to create a cut. Reduction of the bubble diameter is fundamental to improving the cut quality. Methods: A home–built Nd:Glass femtosecond laser is used with a CPA system and 1065 µm wavelength. The pulse repetition rate ranges from 1 to 10 KHz, with a maximum pulse energy of about 60 µJ. The laser delivery system works through an objective lens on an optical table. The samples are fixed to a 3–dimensional moving anterior chamber system, which is connected to a micrometric stepper motor. Human corneas are obtained from the French Eye Bank and are divided into 2 groups, according to their pachymetry: Group 1 (n=10): 1000 µm +/– 75 µm, and Group 2 (n=10): 700 µm +/– 45 µm. The control group is composed of silicon dioxide samples. The treated corneas are analyzed through confocal microscopy. Results: At plasma threshold, the average cavitation bubble diameter is: 6 µm +/– 7µm in the Group 1 corneas, 25 µm +/– 1.5 µm in the Group 2 corneas and 2 +/– 1 µm in the silicon dioxide samples. In group 2 corneas and silicon dioxide samples, the majority of laser pulses generated cavitation bubbles. In group 1 corneas, far fewer of the laser pulses induced cavitation bubbles. The time it takes for one cavitation bubble to disappear is: 90 +/– 10 seconds for a 25 µm cavitation bubble, 25 +/– 5 seconds for a 6 µm cavitation bubble, and 10 minutes in the silicon samples. Conclusions: In more edematous corneas, the cavitation bubble diameter is heterogeneous. This heterogeneity is due to laser beam attenuation by the corneal edema. This information suggests that, in the absence of laser parameter adaptation, the cut quality in edematous and pathological corneas will be less than in clear corneas.

Ultra-High Gradient Channeling Acceleration in Nanostructures: Design/Progress of Proof-of-Concept (POC) Experiments

Abstract: This paper describes simulation analyses on beam and laser (X-ray)-driven accelerations in effective nanotube models obtained from Vsim and EPOCH codes. Experimental setups to detect wakefields are also outlined with accelerator facilities at Fermilab and NIU. In the FAST facility, the electron beamline was successfully commissioned at 50 MeV and it is being upgraded toward higher energies for electron accelerator R&D. The 50 MeV injector beamline of the facility is used for X-ray crystal-channeling radiation with a diamond target. It has been proposed to utilize the same diamond crystal for a channeling acceleration POC test. Another POC experiment is also designed for the NIU accelerator lab with time-resolved electron diffraction. Recently, a stable generation of single-cycle laser pulses with tens of Petawatt power based on thin film compression (TFC) technique has been investigated for target normal sheath acceleration (TNSA) and radiation pressure acceleration (RPA). The experimental plan with a nanometer foil is discussed with an available test facility such as Extreme Light Infrastructure - Nuclear Physics (ELI-NP).

First HPLS Experiments at ELI-NP: Spectral Broadening in Thin Films

Abstract: Following the completion of the installation and testing of the HPLS 2x10PW laser system at ELI-NP, prospective experiments related to spectral broadening in thin films for post-compression were performed at the HPLS 100TW output.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

A roadmap for graphene

Abstract: Recent years have witnessed many breakthroughs in research on graphene (the first two-dimensional atomic crystal) as well as a significant advance in the mass production of this material. This one-atom-thick fabric of carbon uniquely combines extreme mechanical strength, exceptionally high electronic and thermal conductivities, impermeability to gases, as well as many other supreme properties, all of which make it highly attractive for numerous applications. Here we review recent progress in graphene research and in the development of production methods, and critically analyse the feasibility of various graphene applications.

Black Hole Explosions

Abstract: QUANTUM gravitational effects are usually ignored in calculations of the formation and evolution of black holes. The justification for this is that the radius of curvature of space-time outside the event horizon is very large compared to the Planck length (Għ/c3)1/2 ≈ 10−33 cm, the length scale on which quantum fluctuations of the metric are expected to be of order unity. This means that the energy density of particles created by the gravitational field is small compared to the space-time curvature. Even though quantum effects may be small locally, they may still, however, add up to produce a significant effect over the lifetime of the Universe ≈ 1017 s which is very long compared to the Planck time ≈ 10−43 s. The purpose of this letter is to show that this indeed may be the case: it seems that any black hole will create and emit particles such as neutrinos or photons at just the rate that one would expect if the black hole was a body with a temperature of (κ/2π) (ħ/2k) ≈ 10−6 (M/M)K where κ is the surface gravity of the black hole1. As a black hole emits this thermal radiation one would expect it to lose mass. This in turn would increase the surface gravity and so increase the rate of emission. The black hole would therefore have a finite life of the order of 1071 (M/M)−3 s. For a black hole of solar mass this is much longer than the age of the Universe. There might, however, be much smaller black holes which were formed by fluctuations in the early Universe2. Any such black hole of mass less than 1015 g would have evaporated by now. Near the end of its life the rate of emission would be very high and about 1030 erg would be released in the last 0.1 s. This is a fairly small explosion by astronomical standards but it is equivalent to about 1 million 1 Mton hydrogen bombs. It is often said that nothing can escape from a black hole. But in 1974, Stephen Hawking realized that, owing to quantum effects, black holes should emit particles with a thermal distribution of energies — as if the black hole had a temperature inversely proportional to its mass. In addition to putting black-hole thermodynamics on a firmer footing, this discovery led Hawking to postulate 'black hole explosions', as primordial black holes end their lives in an accelerating release of energy.

Materials for terahertz science and technology

Abstract: Terahertz spectroscopy systems use far-infrared radiation to extract molecular spectral information in an otherwise inaccessible portion of the electromagnetic spectrum. Materials research is an essential component of modern terahertz systems: novel, higher-power terahertz sources rely heavily on new materials such as quantum cascade structures. At the same time, terahertz spectroscopy and imaging provide a powerful tool for the characterization of a broad range of materials, including semiconductors and biomolecules.