Control of the spider-like interference structure in photoelectron momentum distributions of a helium atom in a few-cycle nonlinear chirped laser pulse.

We investigate theoretically the photoelectron momentum distributions (PMDs) of the helium atom in the few-cycle nonlinear chirped laser pulse. The numerical results show that the direction of the spider-like interference structure in PMDs exhibits periodic variations with the increase of the chirp parameter. It is illustrated that the direction of the spider-like interference structure is related to the direction of the electron motion by tracking the trajectories of the electrons.

Photoelectron interference of He atoms in the attosecond ionization gating.

We theoretically investigate the photoelectron momentum distribution of He atoms by numerically solving the time-dependent Schro¨dinger equation (TDSE) in few-cycle ionization gating, which is synthesized by two linearly polarized laser pulses. When applying the TDSE, we can clearly see the spider-like structures in the photoelectron momentum spectra. We also find that the spider-like structures can be isolated by changing the relative phase.

Investigation of electron vortices in time-delayed circularly polarized laser pulses with a semiclassical perspective.

We theoretically investigate strong-filed electron vortices in time-delayed circularly polarized laser pulses by a generalized quantum-trajectory Monte Carlo (GQTMC) model. Vortex interference patterns in photoelectron momentum distributions (PMDs) with various laser parameters can be well reproduced by the semiclassical simulation. The phase difference responsible for the interference structures is analytically identified through trajectory-based analysis and simple-man theory, which reveal the underlying mechanism of electron vortex phenomena for both co-rotating and counter-rotating component.

Multiple recollisions in nonsequential double ionization by counter-rotating two-color circularly polarized laser fields.

With the three-dimensional (3D) classical ensemble method, we theoretically investigate the recollision dynamics in strong-field nonsequential double ionization (NSDI) of Ar by counter-rotating two-color circularly polarized laser fields. With the analysis of the NSDI trajectories, we find that not only multiple-recollision but also single-recollision processes occur in the double ionization events. Furthermore, the multiple-recollision and single-recollision processes both undergo the recollision-induced excitation with subsequent ionization (RESI) and recollision-induced ionization (RII).

Nonsequential double ionization of Mg from a doubly excited complex driven by circularly polarized laser field.

With the classical ensemble method, the correlated-electron dynamics of Mg atom from a doubly excited, transition Coulomb complex in few-cycle circularly polarized (CP) laser field at low laser intensity is theoretically investigated. The low energy transfer during the recollision process indicates that the two electrons cannot release directly, but it can pass through a doubly excited state, and then escape with the ionization time difference. The numerical results show that the feature of the sequential double ionization (SDI) can be observed in the nonsequential double ionization (NSDI) process.

Quantum control of electron wave packet during high harmonic process of H2(+) in a combination of a circularly polarized laser field and a Terahertz field.

By solving a two-dimensional time-dependent Schrödinger equation we investigate high harmonic generation (HHG) and isolated attosecond pulse generation for the H2+ molecular ion in a circularly polarized laser pulse combined with a Terahertz (THz) field. The harmonic intensity can be greatly enhanced and a continuum spectrum can be obtained when a THz field is added. The HHG process is studied by the semi-classical three-step model and the time-frequency analysis.

Preparation and microscopy examination of alginate-poly-L-lysine-alginate microcapsules.

Ca-alginate-poly-l-lysine-alginate (APA-Ca) and Ba-alginate-poly-l-lysine-alginate (APA-Ba) microcapsules were prepared and their thickness and surface were examined by light microscopy and scanning electron microscopy. Specifically, light microscopy with frozen section was used to visualize and quantify the thickness of APA membrane, and monitor temporal changes in the thickness of microcapsules during a month long culture in vitro. The section graph of APA microcapsule represents the accurate measurement of layer thickness of APA-Ca with diameter 900 ± 100 and 500 ± 100 μm at 6.