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Todd Ditmire

Bio: Todd Ditmire is an academic researcher from University of Texas at Austin. The author has contributed to research in topics: Laser & Plasma. The author has an hindex of 47, co-authored 342 publications receiving 9506 citations. Previous affiliations of Todd Ditmire include Lawrence Livermore National Laboratory & University of California, Berkeley.
Topics: Laser, Plasma, Ion, Electron, Neutron


Papers
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Journal ArticleDOI
08 Apr 1999-Nature
TL;DR: In this paper, the authors reported the observation of nuclear fusion from the explosions of deuterium clusters heated with a compact, high-repetition-rate table-top laser, achieving an efficiency of about 105 fusion neutrons per joule of incident laser energy.
Abstract: As a form of matter intermediate between molecules and bulk solids, atomic clusters have been much studied1 Light-induced processes in clusters can lead to photo-fragmentation2,3 and Coulombic fission4, producing atom and ion fragments with a few electronvolts (eV) of energy However, recent studies of thephotoionization of atomic clusters with high intensity (>1016 W cm−2) femtosecond laser pulses have shown that these interactions can be far more energetic5,6,7,8,9,10,11,12,13—excitation of large atomic clusters can produce a superheated microplasma that ejects ions with kinetic energies up to 1 MeV (ref 10) This phenomenon suggests that through irradiation of deuterium clusters, it would be possible to create plasmas with sufficient average ion energy for substantial nuclear fusion Here we report the observation of nuclear fusion from the explosions of deuterium clusters heated with a compact, high-repetition-rate table-top laser We achieve an efficiency of about 105 fusion neutrons per joule of incident laser energy, which approaches the efficiency of large-scale laser-driven fusion experiments Our results should facilitate a range of fusion experiments using small-scale lasers, and may ultimately lead to the development of a table-top neutron source, which could potentially find wide application in materials studies

673 citations

Journal ArticleDOI
TL;DR: In this article, the interaction of intense, femtosecond laser radiation with the large (50{endash}200 A) clusters produced in pulsed gas jets was examined.
Abstract: We examine the interaction of intense, femtosecond laser radiation with the large (50{endash}200 A) clusters produced in pulsed gas jets. Both experiment and simulation show that the plasmas produced during these interactions exhibit electron temperatures far in excess of that predicted by above-threshold ionization theory for a low-density gas. Efficient heating of the clusters by the laser is followed by rapid expansion of the clusters and long-lived x-ray emission from hot, decaying, underdense plasma. {copyright} {ital 1996 The American Physical Society.}

666 citations

Journal ArticleDOI
TL;DR: Simulations indicate that with improvements in the laser-pulse focus quality, acceleration to nearly 10 GeV should be possible with the available pulse energy, and the principal physical barriers to multi-gigaelectronvolt acceleration are overcome.
Abstract: Laser-plasma accelerators can produce high-energy electron bunches over just a few centimetres of distance, offering possible table-top accelerator capabilities. Wang et al. break the current 1 GeV barrier by applying a petawatt laser to accelerate electrons nearly monoenergetically up to 2 GeV.

610 citations

Journal ArticleDOI
06 Mar 1997-Nature
TL;DR: In the case of laser-heated xenon clusters, it was shown that the explosion of these superheated clusters ejects ions with substantial kinetic energy up to 1 MeV, four orders of magnitude higher than that achieved in the Coulomb explosion of small molecules as discussed by the authors.
Abstract: Efficient conversion of electromagnetic energy to particle energy is of fundamental importance in many areas of physics A promising avenue for producing matter with unprecedented energy densities is by heating atomic clusters, an intermediate form of matter between molecules and solids1, with high-intensity, ultra-short light pulses2–4 Studies of noble-gas clusters heated with high-intensity (>1016Wcm–2) laser pulses indicate that a highly ionized, very high temperature micro-plasma is produced The explosion of these superheated clusters ejects ions with substantial kinetic energy3–5 Here we report the direct measurement of the ion energy distributions resulting from these explosions We find, in the case of laser-heated xenon clusters, that such explosions produce xenon ions with kinetic energies up to 1 MeV This energy is four orders of magnitude higher than that achieved in the Coulomb explosion of small molecules6, indicating a fundamental difference in the nature of intense laser–matter interactions between molecules and clusters Moreover, it demonstrates that access to an extremely high temperature state of matter is now possible with small-scale lasers

507 citations

Journal ArticleDOI
TL;DR: In this paper, the authors measured the energy absorption efficiency of high intensity, picosecond laser pulses in low density gases composed of large atomic clusters and found that even though the average density of the resulting plasmas is low, energy absorption can be very high, indicating that substantial laser energy is deposited per particle in the plasma.
Abstract: We have measured the energy absorption efficiency of high intensity, picosecond laser pulses in low density gases composed of large atomic clusters. We find that, though the average density of the resulting plasmas is low, the energy absorption can be very high $(g95%)$, indicating that substantial laser energy is deposited per particle in the plasma. Ion energy measurements confirm that this efficient energy deposition results in plasmas with very high (multi-keV) ion temperatures.

282 citations


Cited by
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Journal Article
TL;DR: In this article, a fast Fourier transform method of topography and interferometry is proposed to discriminate between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour generation techniques.
Abstract: A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

3,742 citations

Journal ArticleDOI
TL;DR: In this article, the authors present the landmarks of the 30-odd-year evolution of ultrashort-pulse laser physics and technology culminating in the generation of intense few-cycle light pulses and discuss the impact of these pulses on high-field physics.
Abstract: The rise time of intense radiation determines the maximum field strength atoms can be exposed to before their polarizability dramatically drops due to the detachment of an outer electron. Recent progress in ultrafast optics has allowed the generation of ultraintense light pulses comprising merely a few field oscillation cycles. The arising intensity gradient allows electrons to survive in their bound atomic state up to external field strengths many times higher than the binding Coulomb field and gives rise to ionization rates comparable to the light frequency, resulting in a significant extension of the frontiers of nonlinear optics and (nonrelativistic) high-field physics. Implications include the generation of coherent harmonic radiation up to kiloelectronvolt photon energies and control of the atomic dipole moment on a subfemtosecond $(1{\mathrm{f}\mathrm{s}=10}^{\mathrm{\ensuremath{-}}15}\mathrm{}\mathrm{s})$ time scale. This review presents the landmarks of the 30-odd-year evolution of ultrashort-pulse laser physics and technology culminating in the generation of intense few-cycle light pulses and discusses the impact of these pulses on high-field physics. Particular emphasis is placed on high-order harmonic emission and single subfemtosecond extreme ultraviolet/x-ray pulse generation. These as well as other strong-field processes are governed directly by the electric-field evolution, and hence their full control requires access to the (absolute) phase of the light carrier. We shall discuss routes to its determination and control, which will, for the first time, allow access to the electromagnetic fields in light waves and control of high-field interactions with never-before-achieved precision.

2,547 citations

Journal ArticleDOI
TL;DR: In this paper, the main aspects of ultrashort laser pulse filamentation in various transparent media such as air (gases), transparent solids and liquids are introduced and discussed.

2,282 citations

Journal ArticleDOI
17 Aug 2000-Nature
TL;DR: Computer simulations are used to investigate the structural information that can be recovered from the scattering of intense femtosecond X-ray pulses by single protein molecules and small assemblies and predict that ultrashort, high-intensity X-rays from free-electron lasers that are currently under development will provide a new approach to structural determinations with X- rays.
Abstract: Sample damage by X-rays and other radiation limits the resolution of structural studies on non-repetitive and non-reproducible structures such as individual biomolecules or cells(1). Cooling can slow sample deterioration, but cannot eliminate damage-induc

1,770 citations

Proceedings Article
Ferenc Krausz1
01 Aug 2007
TL;DR: In this paper, an attosecond "oscilloscope" was used to visualize the oscillating electric field of visible light with an oscillator and probe multi-electron dynamics in atoms, molecules and solids.
Abstract: Summary form only given. Fundamental processes in atoms, molecules, as well as condensed matter are triggered or mediated by the motion of electrons inside or between atoms. Electronic dynamics on atomic length scales tends to unfold within tens to thousands of attoseconds (1 attosecond [as] = 10-18 s). Recent breakthroughs in laser science are now opening the door to watching and controlling these hitherto inaccessible microscopic dynamics. The key to accessing the attosecond time domain is the control of the electric field of (visible) light, which varies its strength and direction within less than a femtosecond (1 femtosecond = 1000 attoseconds). Atoms exposed to a few oscillations cycles of intense laser light are able to emit a single extreme ultraviolet (XUV) burst lasting less than one femtosecond. Full control of the evolution of the electromagnetic field in laser pulses comprising a few wave cycles have recently allowed the reproducible generation and measurement of isolated sub-femtosecond XUV pulses, demonstrating the control of microscopic processes (electron motion and photon emission) on an attosecond time scale. These tools have enabled us to visualize the oscillating electric field of visible light with an attosecond "oscilloscope", to control single-electron and probe multi-electron dynamics in atoms, molecules and solids. Recent experiments hold promise for the development of an attosecond X-ray source, which may pave the way towards 4D electron imaging with sub-atomic resolution in space and time.

1,618 citations