Related papers: XUV lasing during strong-field assisted transient …
One of the main difficulties to efficiently generating high-order harmonics in long neutral-gas targets is to reach the phase-matching conditions. One issue is that the medium cannot be sufficiently ionized by the driving laser due to…
In standard lasers, light amplification requires population inversion between an upper and a lower state to break the reciprocity between absorption and stimulated emission. However, in a medium prepared in a specific superposition state,…
D$_2$ molecules, excited by linearly cross-polarized femtosecond extreme ultraviolet (XUV) and near-infrared (NIR) light pulses, reveal highly structured D$^+$ ion fragment momenta and angular distributions that originate from two different…
The operation of a frequency comb at extreme ultraviolet (XUV) wavelengths based on pair-wise amplification and nonlinear upconversion to the 15th harmonic of pulses from a frequency comb laser in the near-infrared range is reported.…
We report on the observation, characterization, and control of the electron dynamics in ionized argon atoms. We utilized an intense mid-infrared (MIR) pulse to create a coherent superposition of the spin-orbit split ground state of the ion.…
Transient extreme ultraviolet (XUV) spectroscopy probes core level transitions to unoccupied valence and conduction band states. Uncertainty remains to what degree the core-hole created by the XUV transition modifies the measurement of…
We study the breakup of $\text{H}_2^+$ exposed to super-intense, femtosecond laser pulses with frequencies greater than that corresponding to the ionization potential. By solving the time-dependent Schr\"odinger equation in an extensive…
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 coherence properties of such a superposition, created by…
We demonstrate time-resolved nonlinear extreme-ultraviolet absorption spectroscopy on multiply charged ions, here applied to the doubly charged neon ion, driven by a phase-locked sequence of two intense free-electron laser pulses.…
We investigate the possibility of maser amplification in hydrogen recombination lines from the galaxies of first generation, at z<~30. Combining analytical and computational approaches, we show that the transitions between the hydrogen…
We use the phenomenon of electromagnetically-induced transparency in a three-level atomic system for hyperfine spectroscopy of upper states that are not directly coupled to the ground state. The three levels form a ladder system: the probe…
The photoelectron momentum distribution in the strong-field ionization has a variety of structures that reveal the complicated dynamics of this process. Recently, we identified a low-energy interference structure in the case of a…
In [I.R. Khairulin et al., submitted to Phys. Rev. Lett.] we propose a method for amplifying a train of sub-femtosecond pulses of circularly or elliptically polarized extreme ultraviolet (XUV) radiation, constituted by high-order harmonics…
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 quantum information to photochemistry. While strong…
The recent development of ultrafast extreme ultraviolet (XUV) coherent light sources bears great potential for a better understanding of the structure and dynamics of matter. Promising routes are advanced coherent control and nonlinear…
We present the main features of CITIUS, a new light source for ultrafast science, generating tunable, intense, femtosecond pulses in the spectral range from IR to XUV. The XUV pulses (about 10^5-10^8 photons/pulse in the range 14-80 eV) are…
Quantum coherence and interference effects in atomic and molecular physics has been extensively studied due to intriguing counterintuitive physics and potential important applications. Here we present one such application of using quantum…
The observation of non-perturbative harmonic emission in solids from ultrashort laser pulses [1] sparked a wave of studies [2,3] as a probe of charge carrier dynamics in solids under strong fields and a route to extreme ultraviolet (XUV)…
We describe numerically the ionization process induced by linearly and circularly polarized XUV attosecond laser pulses on an aligned atomic target, specifically, the excited state…
In this study the generation of energetic coherent extreme ultraviolet (XUV) radiation with controlled polarization, is reported. The XUV radiation results from the process of high harmonic generation (HHG), in a gas phase atomic medium,…