Optical control of an atomic inner-shell x-ray laser

Darvasi, Gabor; Keitel, Christoph H.; Buth, Christian

doi:10.1103/physreva.89.013823

Cited by 5 publications

(10 citation statements)

References 48 publications

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“…This SASE XFEL is used as a seed laser to pump a given atom, and photoionization of the XFEL pulse causes the atom to form holes [34,35,43,44]. In this work, we studied XFEL photoionization pumped neon with inner-shell x-ray transitions of K α 1s −1 − 2p −1 (λ ¼ 1.46 nm).…”

Section: Atomic Inner-shell Lasermentioning

confidence: 99%

“…The XRL intensity Iðz; tÞ is related to the occupancy of the upper and lower layers. The intensity is described by [34,35] dI XRL ðz; tÞ dt…”

Section: Atomic Inner-shell Lasermentioning

confidence: 99%

“…Amplification of spontaneous emitted X-rays on the XRL transition in the exponential gain region is determined by the small-signal gain. The small-signal gain per atom is defined as [30,31,39]…”

Section: Atomic Inner-shell Lasermentioning

confidence: 99%

“…The XRL intensity I(z,t) is influenced by the occupancies of the upper and lower levels, which determine the small-signal gain, in the course of the propagation in the medium. Specically, light with the XRL transition frequency is attenuated for a negative small-signal gain and it is amplified for a positive small-signal gain as described by [30,31]…”

Section: Atomic Inner-shell Lasermentioning

confidence: 99%

“…However, the lack of sufficiently fast and intense X-ray sources has so far precluded the realization of the photo-ionization scheme in the X-ray regime. The introduction of XFEL makes it possible to pump new atomic inner-shell XRL [28][29][30][31] with ultrashort pulse duration, extreme spectral brightness and full temporal coherence. Experimentally, in 2012, An atomic laser based on neon atoms and pumped by a soft XFEL has been achieved at a wavelength of 14.6 ångströms in Linac Coherent Light Source [32]; in 2015, the SPring-8 Angstrom Compact Free Electron Laser use a copper target and report a hard X-ray atomic inner-shell laser operating at a wavelength of 1.5 ångströms [33].…”

Section: Introductionmentioning

confidence: 99%

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Atomic inner-shell radiation seeded free-electron lasers

Zhang

Yan

et al. 2018

Phys. Rev. Accel. Beams

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In order to effectively improve the output quality of x-ray free electron laser (XFEL), we theoretically propose an XFEL scheme seeded by atomic inner-shell laser. Atomic inner-shell lasers based on neutral atoms and pumped by XFEL have been experimentally demonstrated [Rohringer et al., Nature (London) 481, 488 (2012), Yoneda et al., Nature (London) 524, 446 (2015)], which produced sub-femtosecond X-ray pulses with increased temporal coherence. It shows that, by using the inner-shell laser as a seed to modulate the electron bunch, very stable and almost fully-coherent short-wavelength XFEL pulses can be generated. The proposed scheme holds promising prospects in x-ray wavelengths, and even shorter.

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Section: Atomic Inner-shell Lasermentioning

confidence: 99%

“…The XRL intensity Iðz; tÞ is related to the occupancy of the upper and lower layers. The intensity is described by [34,35] dI XRL ðz; tÞ dt…”

Section: Atomic Inner-shell Lasermentioning

confidence: 99%

Section: Atomic Inner-shell Lasermentioning

confidence: 99%

Section: Atomic Inner-shell Lasermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Atomic inner-shell radiation seeded free-electron lasers

Zhang

Yan

et al. 2018

Phys. Rev. Accel. Beams

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Rate equations for nitrogen molecules in ultrashort and intense x-ray pulses

Liu¹,

Berrah²,

Cederbaum³

et al. 2016

J. Phys. B: At. Mol. Opt. Phys.

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We study theoretically the quantum dynamics of nitrogen molecules (N 2 ) exposed to intense and ultrafast x-rays at a wavelength of 1.1 nm (1100 eV photon energy) from the Linac Coherent Light Source (LCLS) free electron laser. Molecular rate equations are derived to describe the intertwined photoionization, decay, and dissociation processes occurring for N 2 .This model complements our earlier phenomenological approaches, the single-atom, symmetric-sharing, and fragmentationmatrix models of J. Chem. Phys. 136, 214310 (2012). Our rate-equations are used to obtain the effective pulse energy at the sample and the time scale for the dissociation of the metastable dication N 2+ 2 . This leads to a very good agreement between the theoretically and experimentally determined ion yields and, consequently, the average charge states. The effective pulse energy is found to decrease with shortening pulse duration. This variation together with a change in the molecular fragmentation pattern and frustrated absorption-an effect that reduces absorption of x-rays due to (double) core hole formation-are the causes for the drop of the average charge state with shortening LCLS pulse duration discovered previously.

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Neon in ultrashort and intense x-rays from free electron lasers

Buth

Beerwerth

Obaid

et al. 2018

J. Phys. B: At. Mol. Opt. Phys.

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We theoretically examine neon atoms in ultrashort and intense x rays from free electron lasers and compare our results with data from experiments conducted at the Linac Coherent Light Source (LCLS). For this purpose, we treat in detail the electronic structure in all possible nonrelativistic cationic configurations using a relativistic multiconfiguration approach. The interaction with the x rays is described in rate-equation approximation. To understand the mechanisms of the interaction, a path analysis is devised which allows us to investigate what sequences of photoionization and decay processes lead to a specific configuration and with what probability. Thereby, we uncover a connection to the mathematics of graph theory and formal languages. In detail, we study the ion yields and find that plain rate equations do not provide a satisfactory description. We need to extend the rate equations for neon to incorporate double Auger decay of a K-shell vacancy and photoionization shake off for neutral neon. Shake off is included for valence and core ionization; the former has hitherto been overlooked but has important consequences for the ion yields from an x-ray energy below the core ionization threshold. Furthermore, we predict the photon yields from xuv and x-ray fluorescence; these allow one insights into the configurations populated by the interaction with the x rays. Finally, we discover that inaccuracies in those Auger decay widths employed in previous studies have only a minor influence on ion and photon yields.Keywords: ultrashort and intense x rays, neon atom, multiconfiguration Dirac-Hartre-Fock, rate equations, free-electron laser, ion yield, photon yield I. INTRODUCTIONAtoms are the basic constituents of aggregates of matter realized in molecules, clusters, and solids. In this way, the study of the interaction of intense and ultrafast x rays with atoms is of fundamental importance for all research involving matter in such light. Intense x rays offer manifold novel perspectives for science such as diffraction experiments with single molecules [1] and x-ray quantum optics [2].Experimentally, research with intense and ultrafast x rays has only recently become a reality by the novel x-ray free electron lasers (FELs) of which there are presently four producing soft to hard x rays: the Linac Coherent Light Source (LCLS) [3,4] in Menlo Park, California, USA, the SPring-8 Angstrom Compact free electron LAser (SACLA) [5] in Sayo-cho, Sayo-gun, Hyogo, Japan, the SwissFEL [6] in Villigen, Switzerland, and the European X-Ray Free-Electron Laser (XFEL) [7] in Hamburg, Germany.The novel FEL facilities which produce x rays with unprecedented characteristics inspire one to investigate processes, known from the strong-field interaction of optical lasers with atoms, but with x rays that go be- * World Wide Web: www.christianbuth.name, electronic mail; christian.buth@web.de yond the well-established one-x-ray-photon science only possible at synchrotron light sources [8]. With x rays the sequential absorption of multiple pho...

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Optical control of an atomic inner-shell x-ray laser

Cited by 5 publications

References 48 publications

Atomic inner-shell radiation seeded free-electron lasers

Atomic inner-shell radiation seeded free-electron lasers

Rate equations for nitrogen molecules in ultrashort and intense x-ray pulses

Neon in ultrashort and intense x-rays from free electron lasers

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