• Santiago de Compostela, Spain 17-21 July 2017

Oral presentation: «Extreme nonlinear response in graphene»

Abstract: High-order harmonic generation (HHG) is a remarkable process resulting from the interaction of physical systems with intense electromagnetic radiation. The generation of high-order harmonics is well-established in atomic and molecular gases. However, much progress have been done towards HHG in solids since the first experimental observation. HHG from solids has burgeoned a great interest, mainly motivated by the quadratic scaling of the harmonic conversion efficiency with the density of the target, as a result of the coherent nature of the process. While semiconductors materials have been well studied, it is not the case for two-dimensional materials as graphene. In this work we present a theoretical approach to describe the induced dynamics responsible for HHG in graphene. We predict the possibility to produce HHG with few-cycle mid-IR laser pulses.

url: website link

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CLEO – ECEQ    European Quantum Electronics Conference

• Munich, Germany 25-29 June 2017

Oral presentation: «Theoretical approaches for time-resolved inner-shell physics and coherent control»

Abstract: The advent of femtosecond x-ray pulses enables the control of inner-shell electron excitations in timescales comparable to intrinsic electron relaxations. A theoretical approach is proposed to account for x-ray interactions and electron relaxations in concurrence.

url: https://www.osapublishing.org/abstract.cfm?uri=EQEC-2017-JSI_1_3

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SPIE Optics + Optoelectronics

• Prague, Czech Republic 24-27 April 2017

Oral presentation: «Time-resolved x-ray spectroscopy for x-ray-induced phenomena»

Abstract: X-ray-pump/x-ray-probe spectroscopy allows investigation of ultrafast x-ray induced molecular dynamics. X-ray absorption and Auger decay leave molecules in manifolds of transient intermediate states in the femtosecond time scale. By using an x-ray probe pulse, we can image nuclear wavepackets as a function of time using ion-ion coincidence spectroscopy to record ion momentum distributions and kinetic energy releases (KERs). Numerical simulations, a timedependent approach that includes both K-shell photoionization and Auger decay, show how the transient intermediate states are projected onto the KERs. At short time delays, the measurements are sensitive to interatomic interactions, whereas at longer delays the contribution from separated ions due to dissociative intermediate states becomes observable. We present simulations for the nitrogen molecule. These simulations have the potential to be extended to more complex molecules.

url: https://www.osapublishing.org/abstract.cfm?uri=EQEC-2017-JSI_1_3

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IWP-RIXS-2017 «International workshop of photoionization and resonant inelastic x-ray scattering»

• Aussois, France 26-31 March 2017

Invited presentation: «X-ray pump — X-ray probe spectroscopy»

Abstract: Novel accelerator-based and laser-based sources allow the generation of femtosecond and attosecond x-ray/XUV pulses. This has opened new perspectives to track in “real time” molecular processes in the natural time scale of electron and nuclei motion. Molecular phenomena initiated by the absorption of an x-ray/XUV photon is one of the most challenging questions for these novel sources. Two-color femtosecond x-ray pulses with controlled time delay enable the study of x-ray induced phenomena with x-ray probing. The site-specificity of those photons allow the excitation of inner-shell electrons in a particular site of the molecule and, with a controlled time delay, the probing of the induced intramolecular dynamics in another site of the same molecule. Also, novel XUV/x-ray sources with a high spatio-temporal degree of coherence are suitable for quantum control schemes involving inner-shell electrons. In this talk, we present new theoretical and experimental results towards this direction and discuss the perspectives of this exciting field.

url: website link