Related papers: Laser-assisted-autoionization dynamics of helium r…
We discuss the dynamics of the two-photon resonant ionization of helium involving two autoionizing states in the presence of two-color laser fields. The first source is tuned around the transition from the ground state to the 2s2p 1Po…
We propose a general technique to retrieve the information of dipole-forbidden resonances in the autoionizing region. In the simulation, a helium atom is pumped by an isolated attosecond pulse in the extreme ultraviolet (EUV) combined with…
We study theoretically the photoabsorption spectra of an attosecond XUV pulse by a laserdressed atomic system. A weak XUV excites an autoionizing state which is strongly coupled to another autoionizing state by a laser. The theory was…
We investigate the possibility to monitor the dynamics of autoionizing states in real time and control the yields of different ionization channels in helium by simulating XUV-pump IR-probe experiments focused on the N=2 threshold. The XUV…
Attosecond pulses can ionize atoms in a coherent process. Since the emerging fragments are entangled, however, each preserves only a fraction of the initial coherence, thus limiting the chance of guiding the ion subsequent evolution. In…
We investigate the laser-assisted single XUV photon double ionization of ground state helium. By solving full six-dimensional time-dependent schr{\"o}dinger equation, we study the correlation and angular distribution. The discussion in…
An extreme ultraviolet (EUV) single attosecond pulse passing through a laser-dressed dense gas is studied theoretically. The weak EUV pulse pumps the helium gas from the ground state to the 2s2p(1P) autoionizing state, which is coupled to…
We propose a new scenario to apply IR-pump-XUV-probe schemes to resolving strong field ionization induced and attosecond pulse driven electron-hole dynamics and coherence in real time. The coherent driving of both the infrared laser and the…
We investigate the photoionization spectrum of helium by attosecond XUV pulses both in the spectral region of doubly excited resonances as well as above the double ionization threshold. In order to probe for convergence, we compare three…
The photoionization of a helium atom by short intense laser pulses is studied theoretically in the vicinity of the $2s2p\,^1P$ doubly-excited state with the intention to investigate the impact of the intensity and duration of the exciting…
We have examined the profile of an isolated autoionizing resonance driven by a pulse of short duration and moderately strong field. The analysis has been based on stochastic differential equations governing the time evolution of the density…
We study resonant two-photon ionization of helium atoms via the $1s3p$, $1s4p$ and $1s5p^1$P$_1$ states using the 15$^\mathrm{th}$ harmonic of a titanium-sapphire laser for the excitation and a weak fraction of the laser field for 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…
Attosecond pump-probe ionization process can be used to prepare atomic ions in the coherent superposition of states with opposite parity. The multiphoton shake-up ionization of Helium, in particular, generates ions with same principal…
An optical coherent control scheme has been proposed and theoretically investigated where an extreme ultraviolet single attosecond pulse (SAP) propagates through a dense helium gas dressed by a time-delayed femtosecond laser pulse. The…
We describe a numerical method that simulates the interaction of the helium atom with sequences of femtosecond and attosecond light pulses. The method, which is based on the close-coupling expansion of the electronic configuration space in…
We report time-resolved photoelectron spectroscopy of the $3s3p$ doubly excited states of helium dressed by an intense near-infrared (NIR) laser field. Using synchronized XUV free-electron-laser and 800-nm NIR laser pulses, we observe a…
The ionization dynamics of helium droplets in a wide size range from 220 to 10^6 He atoms irradiated with intense femtosecond extreme ultraviolet (XUV) pulses of 10^9 {\div} 10^{12} W/cm2 power density is investigated in detail by…
We report on a kinematically complete experiment on strong field double ionization of helium using laser pulses with a wavelength of 394\,nm and intensities of $3.5-5.7\times10^{14}\,W/cm^2$. Our experiment reaches the most complete level…
The field of attosecond physics has expanded significantly in recent years, yet experimental facilities supporting attosecond pump attosecond probe spectroscopy remain rare. Here, we present a newly constructed beamline for the generation…