The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
R W Hellwarth - One of the best experts on this subject based on the ideXlab platform.
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spatiotemporal evolution of focused single cycle Electromagnetic Pulses
Physical Review E, 1999Co-Authors: Simin Feng, Herbert G Winful, R W HellwarthAbstract:We analyze exact solutions of Maxwell's equations that are capable of describing focused single-cycle Electromagnetic Pulses. These finite energy solutions are a subset of Ziolkowski's ``modified power spectrum'' pulse solutions [Phys. Rev A 39, 2005 (1989)]. They display substantial temporal reshaping, time reversal, and polarity reversals as they pass through the focus. The temporal profiles at the focus and in the far field are related by a Hilbert transform in time. These results are explained in terms of the Gouy phase shift of focused beams. We also show that these pulse solutions are natural spatiotemporal modes of an open resonator and propose methods for their practical realization.
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gouy shift and temporal reshaping of focused single cycle Electromagnetic Pulses
Optics Letters, 1998Co-Authors: Simin Feng, Herbert G Winful, R W HellwarthAbstract:We discuss exact solutions of Maxwell’s equations that describe the evolution of single-cycle Electromagnetic Pulses. The solutions are applied to recent observations of the diffraction transformation of terahertz Pulses. In particular, we elucidate the role of the Gouy shift in the temporal reshaping and polarity reversals of single-cycle terahertz Pulses.
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spatiotemporal evolution of focused single cycle Electromagnetic Pulses
Conference on Lasers and Electro-Optics, 1997Co-Authors: Simin Feng, Herbert G Winful, R W HellwarthAbstract:Focused, single-cycle Electromagnetic Pulses have attracted attention as exact solutions of Maxwell’s equations that describe efficient, localized transfer of energy.1
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focused one cycle Electromagnetic Pulses
Physical Review E, 1996Co-Authors: R W Hellwarth, P NouchiAbstract:We describe several families of exact unbounded solutions of Maxwell's equations in vacuum. These solutions depict one- (or 11/2-) cycle Electromagnetic Pulses whose fields are of either transverse magnetic or transverse electric character and are confined to toroidal wave packets that converge to a focus and then diverge in a manner that is expected from familiar rules of diffraction. These ``focused doughnut'' Pulses constitute a subset of the ``modified power spectrum'' pulse solutions discovered by Ziolkowski [Phys. Rev. A 39, 2005 (1989)]. We derive the total energy, the energy spectrum, the ability to accelerate an electron, and other properties of these focused doughnut pulse solutions. \textcopyright{} 1996 The American Physical Society.
Simin Feng - One of the best experts on this subject based on the ideXlab platform.
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spatiotemporal structure of isodiffracting ultrashort Electromagnetic Pulses
Physical Review E, 2000Co-Authors: Simin Feng, Herbert G WinfulAbstract:We present a model of isodiffracting single-cycle and few-cycle ultrashort Electromagnetic Pulses. The model is based on exact solutions of the time-dependent paraxial wave equation with space-time coupling effects included. The spatiotemporal structure of these Pulses is characterized by a scaling parameter which relates off-axis pulse shapes to the axial temporal waveforms. Depending on the spectrum a pulse may transform itself from a single-cycle pulse to a multicycle pulse along the radial coordinate. This model is also used to describe recirculating Pulses in a curved mirror cavity resonator. The Gouy phase shift contributes an absolute phase that results in a pulse-to-pulse temporal instability.
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spatiotemporal evolution of focused single cycle Electromagnetic Pulses
Physical Review E, 1999Co-Authors: Simin Feng, Herbert G Winful, R W HellwarthAbstract:We analyze exact solutions of Maxwell's equations that are capable of describing focused single-cycle Electromagnetic Pulses. These finite energy solutions are a subset of Ziolkowski's ``modified power spectrum'' pulse solutions [Phys. Rev A 39, 2005 (1989)]. They display substantial temporal reshaping, time reversal, and polarity reversals as they pass through the focus. The temporal profiles at the focus and in the far field are related by a Hilbert transform in time. These results are explained in terms of the Gouy phase shift of focused beams. We also show that these pulse solutions are natural spatiotemporal modes of an open resonator and propose methods for their practical realization.
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gouy shift and temporal reshaping of focused single cycle Electromagnetic Pulses
Optics Letters, 1998Co-Authors: Simin Feng, Herbert G Winful, R W HellwarthAbstract:We discuss exact solutions of Maxwell’s equations that describe the evolution of single-cycle Electromagnetic Pulses. The solutions are applied to recent observations of the diffraction transformation of terahertz Pulses. In particular, we elucidate the role of the Gouy shift in the temporal reshaping and polarity reversals of single-cycle terahertz Pulses.
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spatiotemporal evolution of focused single cycle Electromagnetic Pulses
Conference on Lasers and Electro-Optics, 1997Co-Authors: Simin Feng, Herbert G Winful, R W HellwarthAbstract:Focused, single-cycle Electromagnetic Pulses have attracted attention as exact solutions of Maxwell’s equations that describe efficient, localized transfer of energy.1
F Consoli - One of the best experts on this subject based on the ideXlab platform.
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sources and space time distribution of the Electromagnetic Pulses in experiments on inertial confinement fusion and laser plasma acceleration
Philosophical Transactions of the Royal Society A, 2021Co-Authors: F Consoli, L Duvillaret, P Andreoli, M Cipriani, G Cristofari, G Di Giorgio, J Krasa, R De Angelis, D NeelyAbstract:When high-energy and high-power lasers interact with matter, a significant part of the incoming laser energy is transformed into transient Electromagnetic Pulses (EMPs) in the range of radiofrequencies and microwaves. These fields can reach high intensities and can potentially represent a significative danger for the electronic devices placed near the interaction point. Thus, the comprehension of the origin of these Electromagnetic fields and of their distribution is of primary importance for the safe operation of high-power and high-energy laser facilities, but also for the possible use of these high fields in several promising applications. A recognized main source of EMPs is the target positive charging caused by the fast-electron emission due to laser-plasma interactions. The fast charging induces high neutralization currents from the conductive walls of the vacuum chamber through the target holder. However, other mechanisms related to the laser-target interaction are also capable of generating intense Electromagnetic fields. Several possible sources of EMPs are discussed here and compared for high-energy and high-intensity laser-matter interactions, typical for inertial confinement fusion and laser-plasma acceleration. The possible effects on the Electromagnetic field distribution within the experimental chamber, due to particle beams and plasma emitted from the target, are also described. This article is part of a discussion meeting issue 'Prospects for high gain inertial fusion energy (part 2)'.
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electro optic analysis of the influence of target geometry on Electromagnetic Pulses generated by petawatt laser matter interactions
European Physical Journal Web of Conferences, 2018Co-Authors: Timothy Robinson, F Consoli, Samuel Giltrap, Samuel Eardley, N H Stuart, R De Angelis, F Ingenito, C Verona, R A SmithAbstract:We present an analysis of strong laser-driven Electromagnetic Pulses using novel electro-optic diagnostic techniques. A range of targets were considered, including thin plastic foils (20-550 nm) and mass-limited, optically-levitated micro-targets. Results from foils indicate a dependence of EMP on target thickness, with larger peak electric fields observed with thinner targets. Spectral analysis suggests high repeatability between shots, with identified spectral features consistently detected with 30 MeV energies, suggesting the discharge current contribution to EMP is dominant.
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low noise time resolved optical sensing of Electromagnetic Pulses from petawatt laser matter interactions
Scientific Reports, 2017Co-Authors: Timothy Robinson, F Consoli, Samuel Giltrap, Samuel Eardley, G Hicks, E J Ditter, O Ettlinger, N H Stuart, M Notley, R De AngelisAbstract:We report on the development and deployment of an optical diagnostic for single-shot measurement of the electric-field components of Electromagnetic Pulses from high-intensity laser-matter interactions in a high-noise environment. The electro-optic Pockels effect in KDP crystals was used to measure transient electric fields using a geometry easily modifiable for magnetic field detection via Faraday rotation. Using dielectric sensors and an optical fibre-based readout ensures minimal field perturbations compared to conductive probes and greatly limits unwanted electrical pickup between probe and recording system. The device was tested at the Vulcan Petawatt facility with 1020 W cm−2 peak intensities, the first time such a diagnostic has been used in this regime. The probe crystals were located ~1.25 m from target and did not require direct view of the source plasma. The measured signals compare favourably with previously reported studies from Vulcan, in terms of the maximum measured intra-crystal field of 10.9 kV/m, signal duration and detected frequency content which was found to match the interaction chamber’s horizontal-plane fundamental harmonics of 76 and 101 MHz. Methods for improving the diagnostic for future use are also discussed in detail. Orthogonal optical probes offer a low-noise alternative for direct simultaneous measurement of each vector field component.
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time resolved absolute measurements by electro optic effect of giant Electromagnetic Pulses due to laser plasma interaction in nanosecond regime
Scientific Reports, 2016Co-Authors: F Consoli, R De Angelis, L Duvillaret, P Andreoli, M Cipriani, G Cristofari, G Di Giorgio, F Ingenito, C VeronaAbstract:We describe the first electro-optical absolute measurements of Electromagnetic Pulses (EMPs) generated by laser-plasma interaction in nanosecond regime. Laser intensities are inertial-confinement-fusion (ICF) relevant and wavelength is 1054 nm. These are the first direct EMP amplitude measurements with the detector rather close and in direct view of the plasma. A maximum field of 261 kV/m was measured, two orders of magnitude higher than previous measurements by conductive probes on nanosecond regime lasers with much higher energy. The analysis of measurements and of particle-in-cell simulations indicates that signals match the emission of charged particles detected in the same experiment and suggests that anisotropic particle emission from target, X-ray photoionization and charge implantation on surfaces directly exposed to plasma, could be important EMP contributions. Significant information achieved on EMP features and sources is crucial for future plants of laser-plasma acceleration and inertial-confinement-fusion and for the use as effective plasma diagnostics. It also opens to remarkable applications of laser-plasma interaction as intense source of RF-microwaves for studies on materials and devices, EMP-radiation-hardening and Electromagnetic compatibility. The demonstrated extreme effectivity of electric-fields detection in laser-plasma context by electro-optic effect, leads to great potential for characterization of laser-plasma interaction and generated Terahertz radiation.
P H Bucksbaum - One of the best experts on this subject based on the ideXlab platform.
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ionization of rydberg wave packets by subpicosecond half cycle Electromagnetic Pulses
Physical Review Letters, 1996Co-Authors: C Raman, C W S Conover, C I Sukenik, P H BucksbaumAbstract:We have studied the ionization of Rydberg wave packets by subpicosecond, nearly unipolar Electromagnetic field Pulses, in the regime where the duration of the electric field is less than the classical Kepler orbit time 2pn3 for the wave packet. In contrast to the subpicosecond optical Pulses, subpicosecond field Pulses can ionize wave packets when the probability density near the inner turning point of the Kepler orbit is low. The transfer of energy from the Electromagnetic field to essentially free electrons demonstrates that the Pulses are substantially shorter than one field cycle. Such “half-cycle” Pulses can track the wave packet throughout its orbit, in order to study wave packet trajectories or other processes at the quantum-classical boundary.
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ionization of rydberg atoms by subpicosecond half cycle Electromagnetic Pulses
Physical Review Letters, 1993Co-Authors: R R Jones, D You, P H BucksbaumAbstract:We have ionized Rydberg atoms using subpicosecond half-cycle Electromagnetic Pulses. The threshold electric field required to ionize a Rydberg state with effective quantum number ${\mathit{n}}^{\mathrm{*}}$ is found to scale as ${\mathit{n}}^{\mathrm{*}\mathrm{\ensuremath{-}}2}$ for states with ${\mathit{n}}^{\mathrm{*}}$g13 in contradistinction to the ${\mathit{n}}^{\mathrm{*}\mathrm{\ensuremath{-}}4}$ threshold scaling for static field ionization and high order multiphoton ionization. This novel result is explained using a classical model.
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generation of high power sub single cycle 500 fs Electromagnetic Pulses
Optics Letters, 1993Co-Authors: D You, R R Jones, P H Bucksbaum, D R DykaarAbstract:We have generated sub-single-cycle Pulses of Electromagnetic radiation with pulse energies as high as 0.8 μJ and pulse lengths < 500 fs. The 10-dB width of the spectrum is 1.5 THz. The transmitter is a GaAs wafer illuminated at normal incidence by 120-fs, 770-nm Pulses from a Ti:sapphire chirped-pulse amplifier system while a pulsed electric field is applied across the surface. The pulse energy of the far-infrared radiation is found to be a quadratic function of bias field and a nonmonotonic function of laser intensity.
Herbert G Winful - One of the best experts on this subject based on the ideXlab platform.
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spatiotemporal structure of isodiffracting ultrashort Electromagnetic Pulses
Physical Review E, 2000Co-Authors: Simin Feng, Herbert G WinfulAbstract:We present a model of isodiffracting single-cycle and few-cycle ultrashort Electromagnetic Pulses. The model is based on exact solutions of the time-dependent paraxial wave equation with space-time coupling effects included. The spatiotemporal structure of these Pulses is characterized by a scaling parameter which relates off-axis pulse shapes to the axial temporal waveforms. Depending on the spectrum a pulse may transform itself from a single-cycle pulse to a multicycle pulse along the radial coordinate. This model is also used to describe recirculating Pulses in a curved mirror cavity resonator. The Gouy phase shift contributes an absolute phase that results in a pulse-to-pulse temporal instability.
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spatiotemporal evolution of focused single cycle Electromagnetic Pulses
Physical Review E, 1999Co-Authors: Simin Feng, Herbert G Winful, R W HellwarthAbstract:We analyze exact solutions of Maxwell's equations that are capable of describing focused single-cycle Electromagnetic Pulses. These finite energy solutions are a subset of Ziolkowski's ``modified power spectrum'' pulse solutions [Phys. Rev A 39, 2005 (1989)]. They display substantial temporal reshaping, time reversal, and polarity reversals as they pass through the focus. The temporal profiles at the focus and in the far field are related by a Hilbert transform in time. These results are explained in terms of the Gouy phase shift of focused beams. We also show that these pulse solutions are natural spatiotemporal modes of an open resonator and propose methods for their practical realization.
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gouy shift and temporal reshaping of focused single cycle Electromagnetic Pulses
Optics Letters, 1998Co-Authors: Simin Feng, Herbert G Winful, R W HellwarthAbstract:We discuss exact solutions of Maxwell’s equations that describe the evolution of single-cycle Electromagnetic Pulses. The solutions are applied to recent observations of the diffraction transformation of terahertz Pulses. In particular, we elucidate the role of the Gouy shift in the temporal reshaping and polarity reversals of single-cycle terahertz Pulses.
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spatiotemporal evolution of focused single cycle Electromagnetic Pulses
Conference on Lasers and Electro-Optics, 1997Co-Authors: Simin Feng, Herbert G Winful, R W HellwarthAbstract:Focused, single-cycle Electromagnetic Pulses have attracted attention as exact solutions of Maxwell’s equations that describe efficient, localized transfer of energy.1