33 research outputs found

    Extremely high-intensity laser interactions with fundamental quantum systems

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    The field of laser-matter interaction traditionally deals with the response of atoms, molecules and plasmas to an external light wave. However, the recent sustained technological progress is opening up the possibility of employing intense laser radiation to trigger or substantially influence physical processes beyond atomic-physics energy scales. Available optical laser intensities exceeding 10^{22}\;\text{W/cm^2} can push the fundamental light-electron interaction to the extreme limit where radiation-reaction effects dominate the electron dynamics, can shed light on the structure of the quantum vacuum, and can trigger the creation of particles like electrons, muons and pions and their corresponding antiparticles. Also, novel sources of intense coherent high-energy photons and laser-based particle colliders can pave the way to nuclear quantum optics and may even allow for potential discovery of new particles beyond the Standard Model. These are the main topics of the present article, which is devoted to a review of recent investigations on high-energy processes within the realm of relativistic quantum dynamics, quantum electrodynamics, nuclear and particle physics, occurring in extremely intense laser fields.Comment: 58 pages, 26 figures, version accepted by Reviews of Modern Physic

    Power amplification for petawatt Ti: Sapphire lasers: New strategies for high fluence pumping

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    One of the major bottlenecks when we pump large Ti:Sapphire crystals, to reach Petawatt–level laser amplification, is the careful control of the spatial energy distribution of Nd:Glass pump lasers. Commercially available nanosecond Nd:Glass and Nd:YAG lasers exhibit poor spatial profile quality especially in the near and in the intermediate field, which can lead to local hot spots, responsible of damages in crystals, and parasitic transverse lasing enhancement, strongly dependent on the profile of the pump beam . For these reasons, it is mandatory to keep the pump beam intensity profile as flat as possible on the pumped crystal. To guarantee the best pumping conditions we are investigating the combined use of DOE (diffractive optical elements) and optical smoothing techniques. In parallel we are starting a study on laser induced damages mechanisms in crystal. With DOE and microlens arrays we plan to guarantee to the beam a supergaussian shape. Simulation and first experiments with both optical systems show that a flat top spatial profile with less than 10% fluctuations and a 8th order supergaussian is possible with the present technology.Optical smoothing will keep the beam free of hot spots. We especially focused on the smoothing techniques involving optical fibers. This is the first time to our knowledge that this technique is applied to the pumping beams for Ti:Sapphire systems. A deep study of laser-crystal interaction will allow us to fully understand the damages created by hot spots. The knowledge of the phenomena involved in laser damages on Ti:Sapphire is mandatory to control the pumping processes and thresholds. In conclusion, mixing the advantages of these different approaches to overcome this bottleneck will allow us to amplify in a safety way femtosecond laser beams to the Petawatt level using Ti:Sapphire crystals

    Search for stimulated photon-photon scattering in vacuum

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    We have searched for stimulated photon scattering in vacuum at a center of mass photon energy of 0.8 eV. The QED contribution to this process is equivalent to four wave mixing in vacuum. No evidence for γγ\gamma\gamma scattering was observed. The corresponding upper limit of the cross-section is σLim=1.5×1048cm2\sigma_{{Lim}}=1.5 \times 10^{-48}{cm}^{2}
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