Institute For Optik Und Quantenelektronik

Jena, Germany

Institute For Optik Und Quantenelektronik

Jena, Germany
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Amaro P.,University of Heidelberg | Amaro P.,New University of Lisbon | Shah C.,University of Heidelberg | Shah C.,Max Planck Institute for Nuclear Physics | And 9 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2017

We report a measurement of KLL dielectronic recombination in charge states from Kr+34 through Kr+28 in order to investigate the contribution of the Breit interaction for a wide range of resonant states. Highly charged Kr ions were produced in an electron-beam ion trap, while the electron-ion collision energy was scanned over a range of dielectronic recombination resonances. The subsequent Kα x rays were recorded both along and perpendicular to the electron-beam axis, which allowed the observation of the influence of the Breit interaction on the angular distribution of the x rays. Experimental results are in good agreement with distorted-wave calculations. We demonstrate, both theoretically and experimentally, that there is a strong state-selective influence of the Breit interaction that can be traced back to the angular and radial properties of the wave functions in the dielectronic capture. © 2017 American Physical Society.

Aurand B.,Helmholtz Center for Heavy Ion Research | Aurand B.,University Mainz | Aurand B.,ExtreMe Matter Institute | Aurand B.,Lund University | And 24 more authors.
New Journal of Physics | Year: 2013

Experimental results on the acceleration of protons and carbon ions from ultra-thin polymer foils at intensities of up to 6 × 1019 W cm-2 are presented revealing quasi-monoenergetic spectral characteristics for different ion species at the same time. For carbon ions and protons, a linear correlation between the cutoff energy and the peak energy is observed when the laser intensity is increased. Particle-in-cell simulations supporting the experimental results imply an ion acceleration mechanism driven by the radiation pressure as predicted for multi-component foils at these intensities. © IOP Publishing and Deutsche Physikalische Gesellschaft.

Sayler A.M.,Institute For Optik Und Quantenelektronik | Sayler A.M.,Helmholtz Center for Heavy Ion Research | Rathje T.,Institute For Optik Und Quantenelektronik | Rathje T.,Helmholtz Center for Heavy Ion Research | And 7 more authors.
Optics Express | Year: 2011

The pulse lengths of intense few-cycle (4 - 10 fs) laser pulses at 790 nm are determined in real-time using a stereographic above-threshold ionization (ATI) measurement of Xe, i.e. the same apparatus recently shown to provide a precise, real-time, every-single-shot, carrier-envelope phase measurement of ultrashort laser pulses. The pulse length is calibrated using spectral-phase interferometry for direct electric-field reconstruction (SPIDER) and roughly agrees with calculations done using quantitative rescattering theory (QRS). This stereo-ATI technique provides the information necessary to characterize the waveform of every pulse in a kHz pulse train, within the Gaussian pulse approximation, and relies upon no theoretical assumptions. Moreover, the real-time display is a highly effective tool for tuning and monitoring ultrashort pulse characteristics. © 2011 Optical Society of America.

Sayler A.M.,Institute For Optik Und Quantenelektronik | Sayler A.M.,Helmholtz Center for Heavy Ion Research | Rathje T.,Institute For Optik Und Quantenelektronik | Rathje T.,Helmholtz Center for Heavy Ion Research | And 8 more authors.
Optics Letters | Year: 2011

In this Letter we demonstrate a method for real-time determination of the carrier-envelope phase of each and every single ultrashort laser pulse at kilohertz repetition rates. The technique expands upon the recent work of Wittmann and incorporates a stereographic above-threshold laser-induced ionization measurement and electronics optimized to produce a signal corresponding to the carrier-envelope phase within microseconds of the laser interaction, thereby facilitating data-tagging and feedback applications. We achieve a precision of 113 mrad (6:5°) over the entire 2π range. © 2010 Optical Society of America.

Kubel M.,Ludwig Maximilians University of Munich | Kubel M.,Max Planck Institute of Quantum Optics | Alnaser A.S.,Max Planck Institute of Quantum Optics | Alnaser A.S.,American University of Sharjah | And 15 more authors.
New Journal of Physics | Year: 2014

The dissociative ionization of N2O by near-single-cycle laser pulses is studied using phase-tagged ion-ion coincidence momentum imaging. Carrier-envelope phase (CEP) dependences are observed in the absolute ion yields and the emission direction of nearly all ionization and dissociation pathways of the triatomic molecule. We find that laser-field-driven electron recollision has a significant impact on the dissociative ionization dynamics and results in pronounced CEP modulations in the dication yields, which are observed in the product ion yields after dissociation. The results indicate that the directional emission of coincident and ions in the denitrogenation of the dication can be explained by selective ionization of oriented molecules. The deoxygenation of the dication with the formation of coincident + ions exhibits an additional shift in its CEP dependence, suggesting that this channel is further influenced by laser interaction with the dissociating dication. The experimental results demonstrate how few-femtosecond dynamics can drive and steer molecular reactions taking place on (much) longer time scales. © 2014 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Karbstein F.,Helmholtz Center for Heavy Ion Research | Karbstein F.,Friedrich - Schiller University of Jena | Gies H.,Helmholtz Center for Heavy Ion Research | Gies H.,Friedrich - Schiller University of Jena | And 5 more authors.
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

Birefringence is one of the fascinating properties of the vacuum of quantum electrodynamics (QED) in strong electromagnetic fields. The scattering of linearly polarized incident probe photons into a perpendicularly polarized mode provides a distinct signature of the optical activity of the quantum vacuum and thus offers an excellent opportunity for a precision test of nonlinear QED. Precision tests require accurate predictions and thus a theoretical framework that is capable of taking the detailed experimental geometry into account. We derive analytical solutions for vacuum birefringence which include the spatio-temporal field structure of a strong optical pump laser field and an x-ray probe. We show that the angular distribution of the scattered photons depends strongly on the interaction geometry and find that scattering of the perpendicularly polarized scattered photons out of the cone of the incident probe x-ray beam is the key to making the phenomenon experimentally accessible with the current generation of FEL/high-field laser facilities. © 2015 American Physical Society. © 2015 American Physical Society.

Zeidler S.,Astrophysikalisches Institute | Posch T.,Institute For Astronomie | Mutschke H.,Astrophysikalisches Institute | Richter H.,Institute For Astronomie | Wehrhan O.,Institute For Optik Und Quantenelektronik
Astronomy and Astrophysics | Year: 2011

Context. Several astrophysically relevant solid oxides and silicates have extremely small opacities in the visual and near-infrared in their pure forms. Datasets for the opacities and for the imaginary part k of their complex indices of refraction are hardly available in these wavelength ranges. Aims. We aimed at determining k for spinel, rutile, anatase, and olivine, especially in the near-infrared region. Our measurements were made with impurity-containing, natural, and synthetic stardust analogs. Methods. Two experimental methods were used: preparing small sections of natural minerals and synthesizing melt droplets under the electric arc furnace. In both cases, the aborption properties of the samples were measured by transmission spectroscopy. Results. For spinel (MgAl2O4), anatase, rutile (both TiO2), and olivine ((Mg,Fe)2SiO4), the optical constants have been extended to the visual and near-infrared. We highlight that the individual values of k(λ) and the absorption cross section Qabs(λ) depend strongly on the content in transition metals like iron. Based on our measurements, we infer that k values below 10-5 are very rare in natural minerals including stardust grains, if they occur at all. Conclusions. Data for k and Qabs(λ) are important for various physical properties of stardust grains such as temperature and radiation pressure. With increasing Qabs(λ) due to impurities, the equilibrium temperature of small grains in circumstellar shells increases as well. We discuss why and to what extent this is the case. © 2010 ESO.

Strohaber J.,Texas A&M University | Kaya G.,Texas A&M University | Kaya N.,Texas A&M University | Hart N.,Texas A&M University | And 4 more authors.
Optics Express | Year: 2011

We present an in situ beam characterization technique to analyze femtosecond optical beams in a folded version of a 2f-2f setup. This technique makes use of a two-dimensional spatial light modulator (SLM) to holographically redirect radiation between different diffraction orders. This manipulation of light between diffraction orders is carried out locally within the beam. Because SLMs can withstand intensities of up to , this makes them suitable for amplified femtosecond radiation. The flexibility of the SLM was demonstrated by producing a diverse assortment of "soft apertures" that are mechanically difficult or impossible to reproduce. We test our method by holographically knife-edging and tomographically reconstructing both continuous wave and broadband radiation in transverse optical modes. 11 2 10 W/cm I ©2011 Optical Society of America.

Strohaber J.,Texas A&M University | Zhi M.,Texas A&M University | Sokolov A.V.,Texas A&M University | Kolomenskii A.A.,Texas A&M University | And 2 more authors.
Optics Letters | Year: 2012

Experimental results from the generation of Raman sidebands using optical vortices are presented. By generating two sets of sidebands originating from different locations in a Raman-active crystal, one set containing optical orbital angular momentum and the other serving as a reference, Young's double slit experiment was simultaneously realized for each sideband. The interference between the two sets of sidebands was used to determine the helicity and topological charge in each order. Topological charges in all orders were found to be discrete and follow selection rules predicted by a cascaded Raman process. © 2012 Optical Society of America.

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