371 citations · 2.6k across the 45 of their papers we have counts for
34 papers · 1 filter
Breakdown of the isotropic asymptotic approximation in two-colour photoionisation
Sooraj Rajendran, Miguel Benito de Lama, Praveen Kumar Maroju +24
The Wigner delay is defined as the energy derivative of the scattering phase of a particle in a given potential, unveiling the time taken (or gained) due to the interaction. The ch…
Orbital distortion and parabolic channel effects transform minima in molecular ionization probabilities into maxima
Imam S. Wahyutama, Denawakage D. Jayasinghe, Francois Mauger +2
In the tunneling regime and at sufficiently low field amplitudes, the shape of orientation-dependent molecular ionization rate curves usually resembles the shape of the ionized orb…
Quantitative comparison of TDDFT-calculated HHG yields in ring-shaped organic molecules
Stephanie N. Armond, Kyle A. Hamer, Ravi Bhardwaj +4
We compare the high-harmonic-generation (HHG) yield driven by a mid-infrared laser in three organic ring-shaped molecules, calculated using time-dependent density-functional theory…
Strong-field ionization with few-cycle, mid-infrared laser pulses induces a localized ionization followed by long-lasting charge migration in halogenated organic molecules
Kyle A. Hamer, Francois Mauger, Kenneth Lopata +2
We show that applying a few-femtosecond mid-infrared laser pulse parallel to the backbone of a halogenated, conjugated organic molecule induces localized ionization followed by lon…
Tracking Charge Migration with Frequency-Matched Strobo-Spectroscopy
Kyle A. Hamer, Aderonke S. Folorunso, Kenneth Lopata +3
We present frequency-matched strobo-spectroscopy (FMSS) of charge migration (CM) in bromobutadiyne, simulated with time-dependent density-functional theory. CM+FMSS is a pump-probe…
All-Electron, Density Functional-Based Method for Angle-Resolved Tunneling Ionization in the Adiabatic Regime
Imam S. Wahyutama, Denawakage D. Jayasinghe, François Mauger +3
We develop and test a method that integrates many-electron weak-field asymptotic theory (ME-WFAT) [Phys. Rev. A 89, 013421 (2014)] in the integral representation (IR) into the dens…
Characterizing Particle-Like Charge Migration Dynamics with High-Harmonic Sideband Spectroscopy
Kyle A. Hamer, Francois Mauger, Aderonke S. Folorunso +5
We introduce high-harmonic sideband spectroscopy (HHSS) and show that it can be a robust probe of attosecond charge migration (CM) in a halogenated carbon-chain molecule. We simula…
Probing Stark-induced nonlinear phase variation with opto-optical modulation
E. R. Simpson, M. Labeye, S. Camp +6
We extend the recently developed technique of opto-optical modulation (OOM) to probe state-resolved ac-Stark-induced phase variations of a coherently excited ensemble of helium ato…
Phase Control of Attosecond Pulses in a Train
Chen Guo, Anne Harth, Stefanos Carlström +12
Ultrafast processes in matter can be captured and even controlled by using sequences of few-cycle optical pulses, which need to be well characterized, both in amplitude and phase.…
Quantum Coherence in Photo-Ionization with Tailored XUV Pulses
Stefanos Carlström, Johan Mauritsson, Kenneth J. Schafer +2
Ionization with ultrashort pulses in the extreme ultraviolet (XUV) regime can be used to prepare an ion in a superposition of spin--orbit substates. In this work, we study the cohe…
Controlled free-induction decay in the extreme ultraviolet
Samuel Bengtsson, Esben W. Larsen, David Kroon +8
Coherent sources of attosecond extreme ultraviolet (XUV) radiation present many challenges if their full potential is to be realized. While many applications benefit from the broad…
Spatially and spectrally resolved quantum path interference with chirped driving pulses
Stefanos Carlström, Jana Preclíková, Eleonora Lorek +7
We measure spectrally and spatially resolved high-order harmonics generated in argon using chirped multi-cycle laser pulses. Using a stable, high-repetition rate laser we observe d…
Role of Excited States In High-order Harmonic Generation
Samuel Beaulieu, Seth Camp, Dominique Descamps +8
We investigate the role of excited states in High-order Harmonic Generation by studying the spectral, spatial and temporal characteristics of the radiation produced near the ioniza…
Attosecond Transient Absorption in Dense Gases: Exploring the Interplay between Resonant Pulse Propagation and Laser-Induced Line Shape Control
Chen-Ting Liao, Seth Camp, Kenneth J. Schafer +2
We investigate the evolution of extreme ultraviolet (XUV) spectral lineshapes in an optically-thick helium gas under near-infrared (IR) perturbation. In our experimental and theore…
Phase metrology with multi-cycle two-colour pulses
Carl Leon Michael Petersson, Stefanos Carlström, Kenneth J Schafer +1
Strong-field phenomena driven by an intense infrared (IR) laser depend on during what part of the field cycle they are initiated. By changing the sub-cycle character of the laser e…
Semi-Classical Wavefunction Perspective to High-Harmonic Generation
Francois Mauger, Paul Abanador, Kenneth Lopata +2
We introduce a semi-classical wavefunction (SCWF) model for strong-field physics and attosecond science. When applied to high harmonic generation (HHG), this formalism allows one t…
The interplay between resonant enhancement and quantum path dynamics in harmonic generation in helium
Seth Camp, Kenneth J. Schafer, Mette B. Gaarde
We present a theoretical study of the influence of resonant enhancement on quantum path dynamics in the generation of harmonics above and below the ionization threshold in helium.…
Sub-cycle ionization dynamics revealed by trajectory resolved, elliptically-driven high-order harmonic generation
E. W. Larsen, S. Carlstrom, E. Lorek +6
The sub-cycle dynamics of electrons driven by strong laser fields is central to the emerging field of attosecond science. We demonstrate how the dynamics can be probed through high…
Beyond the single-atom response in absorption lineshapes: Probing a dense, laser-dressed helium gas with attosecond pulse trains
Chen-Ting Liao, Arvinder Sandhu, Seth Camp +2
We investigate the absorption line shapes of laser-dressed atoms beyond the single-atom response, by using extreme ultraviolet (XUV) attosecond pulse trains to probe an optically t…
High harmonic generation from Bloch electrons in solids
Mengxi Wu, Shambhu Ghimire, David A. Reis +2
We study the generation of high harmonic radiation by Bloch electrons in a model transparent solid driven by a strong mid-infrared laser field. We solve the single-electron time-de…
Multiphoton transitions for delay-zero calibration in attosecond spectroscopy
Jens Herrmann, Matteo Lucchini, Shaohao Chen +7
The exact delay-zero calibration in an attosecond pump-probe experiment is important for the correct interpretation of experimental data. In attosecond transient absorption spectro…
Attosecond pulse shaping around a Cooper minimum
S. B. Schoun, R. Chirla, J. Wheeler +5
High harmonic generation (HHG) is used to measure the spectral phase of the recombination dipole matrix element (RDM) in argon over a broad frequency range that includes the 3p Coo…
Quantum interference in attosecond transient absorption of laser-dressed helium atoms
Shaohao Chen, Mengxi Wu, Mette B. Gaarde +1
We calculate the transient absorption of an isolated attosecond pulse by helium atoms subject to a delayed infrared (\ir) laser pulse. With the central frequency of the broad attos…
Influence of Phase Matching on the Cooper Minimum in Ar High Harmonic Spectra
J. P. Farrell, L. S. Spector, B. K. McFarland +4
We study the influence of phase matching on interference minima in high harmonic spectra. We concentrate on structures in atoms due to interference of different angular momentum ch…