147 citations · 1.5k across the 54 of their papers we have counts for
21 papers · 1 filter
Zero-energy photoelectric effect
Sajad Azizi, Ulf Saalmann, Jan M. Rost
We predict a near-threshold ("zero energy") peak in multi-photon ionization for a dynamical regime where the photon frequency is large compared to the binding energy of the electro…
Strong-field quantum control in the extreme ultraviolet using pulse shaping
Fabian Richter, Ulf Saalmann, Enrico Allaria +40
Tailored light-matter interactions in the strong coupling regime enable the manipulation and control of quantum systems with up to unit efficiency, with applications ranging from q…
Strong-field photoionization by circularly polarized light
Jonathan Dubois, Camille Lévêque, Jérémie Caillat +3
We demonstrate that strong-field ionization of atoms driven by circularly polarized light becomes an adiabatic process when described in the frame rotating with the laser field. As…
Symmetry-induced decoherence-free subspaces
Jonathan Dubois, Ulf Saalmann, Jan Michael Rost
Preservation of coherence is a fundamental yet subtle phenomenon in open systems. We uncover its relation to symmetries respected by the system Hamiltonian and its coupling to the…
Enhanced high-order harmonics through periodicity breaks: from backscattering to impurity states
Chuan Yu, Ulf Saalmann, Jan M. Rost
Backscattering of delocalized electrons has been recently established [Phys. Rev. A 105, L041101 (2022)] as a mechanism to enhance high-order harmonic generation (HHG) in periodic…
Non-adiabatic ionization with tailored laser pulses
Sajad Azizi, Ulf Saalmann, Jan M Rost
Non-adiabatic photo-ionization is difficult to control as it relies on the derivatives of the envelope and not on phase-details of the short ionizing pulse. Here, we introduce a ca…
High harmonics from backscattering of delocalized electrons
Chuan Yu, Ulf Saalmann, Jan M. Rost
It is shown that electron backscattering can enhance high-harmonic generation in periodic systems with broken translational symmetry. Paradigmatically, we derive for a finite chain…
Semiclassical Lindblad master equation for spin dynamics
J. Dubois, Ulf Saalmann, Jan M. Rost
We derive the semi-classical Lindblad master equation in phase space for both canonical and non-canonical Poisson brackets using the Wigner-Moyal formalism and the Moyal star-produ…
Perspectives for analyzing non-linear photo ionization spectra with deep neural networks trained with synthetic Hamilton matrices
Sajal Kumar Giri, Lazaro Alonso, Ulf Saalmann +1
We have constructed deep neural networks, which can map fluctuating photo-electron spectra obtained from noisy pulses to spectra from noise-free pulses. The network is trained on s…
Proper time delays measured by optical streaking
Ulf Saalmann, Jan M Rost
The generation of a streaking spectrogram is based on energy absorption from the streaking laser. Investigating this absorption we show rigorously under which condition the measure…
Purifying electron spectra from noisy pulses with machine learning using synthetic Hamilton matrices
Sajal Kumar Giri, Ulf Saalmann, Jan M. Rost
Photo-electron spectra obtained with intense pulses generated by free-electron lasers through self-amplified spontaneous emission are intrinsically noisy and vary from shot to shot…
Boosting terahertz-radiation power with two-color circularly polarized midinfrared laser pulses
V. A. Tulsky, M. Baghery, U. Saalmann +1
A way to considerably enhance terahertz radiation, emitted in the interaction of intense mid-infrared laser pulses with atomic gases, in both the total energy and the electric-fiel…
Adiabatic passage to the continuum
Ulf Saalmann, Sajal Kumar Giri, Jan M. Rost
We demonstrate that by changing the direction of the chirp in VUV pulses one can switch between excitation and ionization with very high contrast, if the carrier frequency of the l…
Floquet approach for dynamics in short and intense laser pulses
Lukas Medišauskas, Ulf Saalmann, Jan-Michael Rost
We present a two-timescale Floquet method that allows one to apply the Kramers-Henneberger approach to short pulses and arbitrary laser frequencies. An efficient numerical procedur…
Recovery of dynamic interference
Mehrdad Baghery, Ulf Saalmann, Jan M. Rost
We develop general quantitative criteria for dynamic interference, a manifestation of double-slit interference in time which should be realizable with brilliant state-of-the-art hi…
Dynamical characteristics of Rydberg electrons released by a weak electric field
Elias Diesen, Ulf Saalmann, Martin Richter +3
The dynamics of ultra-slow electrons in the combined potential of an ionic core and a static electric field is discussed. With state-of-the-art detection it is possible to create s…
The envelope Hamiltonian for electron interaction with ultrashort pulses
Koudai Toyota, Ulf Saalmann, Jan M. Rost
For ultrashort VUV pulses with a pulse length comparable to the orbital time of the bound electrons they couple to we propose a simplified envelope Hamiltonian. It is based on the…
Virtual single-photon transition interrupted: time-gated optical gain and loss
Jens Herrmann, Matthias Weger, Reto Locher +6
The response of matter to an optical excitation consists essentially of absorption and emission. Traditional spectroscopy accesses the frequency-resolved and time-integrated respon…
Energy bunching in soft recollisions revealed with long-wavelength few-cycle pulses
Alexander Kästner, Ulf Saalmann, Jan M. Rost
Soft recollisions are laser-driven distant collisions of an electron with its parent ion. Such collisions may cause an energy bunching, since electrons with different initial drift…
Electron-energy bunching in laser-driven soft recollisions
Alexander Kästner, Ulf Saalmann, Jan M. Rost
We introduce soft recollisions in laser-matter interaction. They are characterized by the electron missing the ion upon recollision in contrast to the well-known head-on collisions…
Strong field dynamics with ultrashort electron wave packet replicas
P. Riviere, O. Uhden, U. Saalmann +1
We investigate theoretically electron dynamics under a VUV attosecond pulse train which has a controlled phase delay with respect to an additional strong infrared laser field. Usin…