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Showing 1 to 20 of 49 for “"high harmonic"”.
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Modelling of capillary high harmonic generation
High harmonic generation (HHG) is now an accepted method for laboratory based generation of XUV and soft x-ray light. HHG produces pulses that are highly coherent, with a pulse length in the femtosecond or attosecond timescales. To predict the XUV output from an HHG experiment, both the emission …
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Limits of long wavelength High Harmonic Generation
… pushing for long wavelength driver pulses for High Harmonic Generation (HHG). The advantage of longer wavelengths is that the cut-off of the harmonic spectrum can be increased without the need for large electric fields. Large electric field is undesirable because it leads to large plasma …
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Limits of High Harmonic Generation conversion efficiency
High Harmonic Generation (HHG) is a fascinating phenomenon from both fundamental and technological point of view. It enables the generation of attosecond pulses and can have applications in EUV lithography and bio-microscopy. HHG can be described by the Three Step Model (TSM), due to the three …
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Development and spatio-spectral mapping of a capillary high harmonic source
… development and operation of a capillary based High Harmonic Generation (HHG) system. Using this system a coherent beam of soft x-rays is generated, studied and applied. A series of experiments was then undertaken in order to deepen our knowledge of the HHG process and to optimise the …
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Capturing atomic and electronic motion with high harmonic generation light pulses
Contains fulltext : 90924.pdf (Publisher’s version ) (Open Access)
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Homodyne High-harmonic Spectroscopy: Coherent Imaging of a Unimolecular Chemical Reaction
At the heart of high harmonic generation lies a combination of optical and collision physics entwined by a strong laser field. An electron, initially tunnel-ionized by the field, driven away then back in the continuum, finally recombines back to rest in its initial ground state via a radiative …
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High harmonic generation and attosecond dynamics in small organic molecules and biomolecules
… we report on calculations of ionization and high harmonic generation (HHG) in a number of small molecules, using the EDAMAME code, which combines a TDDFT description of electronic dynamics with a classical treatment of ionic dynamics. The work is divided into two main areas.<br/><br/> In the …
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High harmonic generation by short laser pulses: time-frequency behavior and applications to attophysics
High harmonic generation (HHG) is a process in which noble gas atoms excited by an intense laser field at frequency ω<sub>1</sub> emit radiation of higher frequencies that are odd integer multiples of ω<sub>1</sub>. Driven by an infrared laser, high harmonic radiation can span from the optical into …
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Tabletop coherent extreme ultraviolet and soft X-ray sources based on high harmonic generation
High harmonic generation (HHG) is a fascinating strong-field physics phenomenon that occurs when a laser pulse with a moderate intensity interacts with atoms and partially ionizes the atoms. A series of harmonics are generated at similar efficiencies and extend to a few tenth, even thousandth, …
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Study of High Harmonic Fast Waves Interactions in the Scrape off Layer of NSTX-U
High-harmonic fast wave (HHFW) heating experiments in the National Spherical Torus Experiment (NSTX) at Princeton Plasma Physics Laboratory (PPPL) have shown that up to 60% of the injected power can be lost in the Scrape-Off Layer (SOL) when the fast wave is able to propagate in front of the …
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The influence of high harmonic force on fatigue life and its prediction via coupled inline-crossflow VIV modeling
… However, the cost of these measures can be high. Effective VIV and fatigue prediction programs offer the potential for design and replacement schedule optimization. For a long time, researchers believed that these oscillations were mainly in the crossflow direction (a direction perpendicular …
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Adaptive control of coherent soft X-rays
… x-rays through the nonlinear optical process of high-harmonic generation allows for the monitoring of the fastest events ever observed in the laboratory. The attosecond pulses produced are the fundamental tool for the time-resolved study of electron motion in atoms, molecules, clusters, liquids …
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Designing a nanoscale x-ray source: towards single molecule x-ray scattering
… of a femtosecond X-ray source based on high harmonic generation in an argon filled hollow capillary waveguide. The system has demonstrated excellent efficiency at generating harmonics in the range 20-50 eV and is tuneable by exploiting the ionization-induced blue-shift that occurs in the …
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Ultrafast electron dynamics in Fe(CO)5 and Cr(CO)6
… time-resolved photoelectron spectroscopy at a high harmonic setup. In both of these metal carbonyls, a UV photon can induce the dissociation of one or more ligands of the complex. The mechanism of the dissociation has been debated over the last decades. The electronic dynamics of the first …
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Modeling of nonlinear ultrashort optical pulse propagation
… nonlinear wave mixing, plasma blue-shifting, and high harmonic generation. I also demonstrate the capabilities of our versatile simulation package, which can handle optical pulse propagation through a host of geometries and guiding structures. Finally, the simulation package is used to investigate …
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High intensity femtosecond enhancement cavities
To produce extreme ultraviolet radiation via high harmonic generation (HHG) in rare gases, light intensities in excess of 1014 W/cm 2 are required. Usually such high intensity are obtained by parametric amplification of laser pulses, which in turn reduces the pulse repetition rate to a few kHz. …
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Extreme ultraviolet polarization optics for polarimetry of structured high harmonics
High Harmonic Generation (HHG) is a leading way to generate table-top coherent extreme ultraviolet (EUV) and attosecond pulses. Polarization characterization in this spectral range is important to understand the phenomena of HHG and quantify the light used for experiments. Furthermore, polarization …
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EMTP simulation of an active filter operating with weak AC distribution system
… loads cause disturbance on the ac bus due to high harmonic load currents. Traditionally passive filters are used for filtering these load harmonics. Recent technological advances have enabled the use of high frequency switching devices in the development of active filtering techniques. In this …
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Controlling Laser High-Order Harmonic Generation Using Weak Counter-Propagating Light
Laser high-order harmonic generation in the presence of relatively weak interfering light is investigated. The interfering pulses intersect the primary harmonic-generating laser pulse at the laser focus. The interfering light creates a standing intensity and phase modulation on the field, which …
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