Related papers: Enhanced Population on Ionic Excited States by Syn…
We report on the lasing in air and pure nitrogen gas pumped by a single 800 nm femtosecond laser pulse. Depending on gas pressure, incident laser power and beam convergence, different lasing lines are observed in the forward direction with…
We simulate the pump-probe experiments of lasing in molecular nitrogen ions with particular interest on the effects of rotational wave-packet dynamics. Our computations demonstrate that the coherent preparation of rotational wave packets in…
We demonstrate the efficient generation of Be$^+$ ions with a 60 ns and 150 nJ laser pulse near 235 nm for two-step photo-ionization, proven by subsequent counting the number of ions loaded into a linear Paul trap. The bandwidth and power…
We propose a broadband, femtosecond two-photon excitation scheme for efficient population transfer to the ultra-narrow linewidth $1s2s\ ^1S_0$ metastable state in helium. Using $120$ nm vacuum ultraviolet (VUV) femtosecond laser pulses, we…
We study the nonlinear and resonant process of two-photon ionization of atoms (He and H) in a pump-probe scheme. The pump pulse prepares the quantum system in a superposition of the ground state and an excited bound state. By varying the…
The ionization of atoms with sequences of attosecond pulses gives rise to excited ionic states that are entangled with the emitted photoelectron. Still, the ionic ensemble preserves some coherence that can be controlled through the laser…
Efficient production of nuclear isomers is critical for pioneering applications, like nuclear clocks, nuclear batteries, clean nuclear energy, and nuclear {\gamma}-ray lasers. However, due to small production cross sections and quick…
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…
The laser-like coherent emission at 391nm from N$_2$ gas irradiated by strong 800nm pump laser and weak 400nm seed laser is theoretically investigated. Recent experimental observations are well simulated, including temporal profile, optical…
Ionization of acetylene by linearly-polarized, vacuum ultraviolet (VUV) laser pulses is modelled using time-dependent density functional theory. Several laser wavelengths are considered including one that produces direct ionization to the…
Pump-probe photoionization has been used to map the relaxation processes taking place from highly vibrationally excited levels of the S2 state of azulene, populated directly or via internal conversion from the S4 state. Photoelectron…
We propose a novel scheme for the population and depletion of nuclear isomers. The scheme combines the $\gamma$-photons with energies $\gtrsim 10$ keV emitted during the interaction of a contemporary high-intensity laser pulse with a plasma…
Quantum squeezed states enable precision measurements beyond the standard quantum limit, but conventional solid-state media fundamentally limit pump intensities to the ionization threshold. We demonstrate that plasma waves can mediate…
The kinetic energy distribution of D$^+$ ions resulting from the interaction of a femtosecond laser pulse with D$_2$ molecules is calculated based on the rescattering model. From analyzing the molecular dynamics, it is shown that the…
We investigate dissociative single and double ionization of HeH+ induced by intense femtosecond laser pulses. By employing a semi-classical model with nuclear trajectories moving on field-dressed surfaces and ionization events treated as…
We present a joint experimental and theoretical study on strong-field photo-ionization of sodium atoms using chirped femtosecond laser pulses. By tuning the chirp parameter, selectivity among the population in the highly excited states 5p,…
We extend a recently developed three-dimensional semiclassical model [\href{https://journals.aps.org/pra/abstract/10.1103/PhysRevA.109.033106}{Phys. Rev. \textbf{A} 109, 033106 (2024)}] to study multielectron ionization and the formation of…
A pump source is one of the essential prerequisites in order to achieve lasing, and, in most cases, a stronger pump leads to higher laser power at the output. However, this behavior may be suppressed if two pump beams are used. In this…
We present measurements on pulsed four-wave mixing involving a Rydberg state in an atomic vapor cell. The excitation to the Rydberg state is conducted by a pulsed two-photon excitation on the nanosecond timescale that is combined with a…
Experimental results, supported by precise modelling, demonstrate optimisation of a plasma-based injector with intermediate laser pulse energy ($<1$ J), corresponding to a normalised vector potential $a_0 = 2.15$, using ionisation injection…