Session 3 – STRONG-FIELD PROCESSES I

Chair: Zhiyi Wei, Institute of Physics, Beijing, China

#9, 13:30 – 14:00 Attosecond charge migration and its laser control, P. M. KRAUS, B. MIGNOLET, D. BAYKUSHEVA, A. RUPENYAN, L. HORNÝ, E. F. PENKA, O. I. TOLSTIKHIN, J. SCHNEIDER, F. JENSEN, L. B. MADSEN, A. D. BANDRAUK, F. REMACLE AND H. J. WÖRNER, We advance high-harmonic spectroscopy to resolve molecular charge migration in time and space and simultaneously demonstrate extensive control over the process. A multidimensional approach enables us to reconstruct both quantum amplitudes and phases with a resolution of 70-130 attoseconds and to separately reconstruct field-free and laser-driven charge migration. Our techniques make charge migration in molecules measurable on the attosecond time scale and open new avenues for laser control of electronic primary processes.

#10, 14:00 – 14:15 Transverse electron momentum distribution with pulses of varying ellipticity: Cross-over from tunneling to over the barrier ionization regimes, IGOR IVANOV, ANATOLI KHEIFETS, J.E. CALVERT, S. GOODALL, X. WANG, HAN XU, A.J. PALMER, D. KIELPINSKI, I.V. LITVINYUK, AND R.T.SANG, We study transverse electron momentum distribution (TEMD) in strong field atomic ionization driven by laser pulses with varying ellipticity. We show that the TEMD in the tunneling and over the barrier ionization (OBI) regimes evolves in a qualitatively different way when the ellipticity parameter ε describing polarization state of the driving laser pulse increases. In the tunneling regime, the TEMD gradually evolves from a sharp cusp to a smooth Gaussian when ε varies from 0 to 1 (from linear to circular). In the OBI regime, the cusp remains for all ellipticities. This qualitative difference is a distinctive marker of OBI.

#11, 14:15 – 14:30 Dynamic Core Polarization in Strong-Field ionization and High-order Harmonic Generation of CO molecules, BIN ZHANG, JIANMIN YUAN, AND ZENGXIU ZHAO, The orientation-dependent strongfield ionization and high-order harmonic generation of CO molecules is investigated using the fully propagated three-dimensional time-dependent Hartree-Fock theory. We identify that the dynamic core polarization plays an important role in both these two processes, which is helpful for the future development of the ionization and HHG theories of molecules beyond the single active electron approximation.

#12, 14:30 – 14:45 Dynamic exchange and polarization in strong field ionization of molecules, VINAY PRAMOD MAJETY AND ARMIN SCRINZI, A novel hybrid anti-symmetrized coupled channels approach is used to study the undelying mechanisms in strong field ionization of molecules. It allows for the first time a systematic study of the role of various multi-electron effects like the interchannel coupling, ionic core polarization and exchange in strong field ionization. We investigated several experimentally interesting systems like N2, CO and CO2 using this method and it fully explains the observed angle dependent ionization profiles. Our calculations resolve the long debated mechanism behind the angle dependent emission of CO2, which happens to be a simple single channel process that is significantly influenced by the exchange interaction between the ionizing electron and the residual ion.

#13, 14:45 – 15:00 Sub-laser-cycle control of coupled electron-nuclear dynamics at a conical intersection, MARIA RICHTER, FOUDHIL BOUAKLINE, JESÚS GONZÁLEZ-VÁZQUEZ, LARA MARTÍNEZ-FERNÁNDEZ, INÉS CORRAL, SERGUEI PATCHKOVSKII, FELIPE MORALES, MISHA IVANOV, FERNANDO MARTÍN, AND OLGA SMIRNOVA, We discuss new opportunities for controlling coupled electron-nuclear dynamics, offered by the advent of nearly singlecycle, phase-stable mid-infrared laser pulses. The key idea of the control scheme is to match the time scale of the laser field oscillations to the characteristic time scale of the wave packet transit through the conical intersection (CI) region. The instantaneous laser field changes the shape and the position of the conical intersection as the wave packet passes through. As the CI moves in the laser field, it ‘slices’ through the wave packet, sculpting it in the coordinate and momentum space.