B-Spline with Symplectic Algorithm Method for Solution of Time-Dependent Schrodinger Equations

A B-spline with the symplectic algorithm method for the solution of time-dependent Schrodinger equations （TDSEs） is introduced. The spatial part of the wavefunction is expanded by B-spline and the time evolution is given in a symplectic scheme. This method allows us to obtain a highly accurate and stable solution of TDSEs. The effectiveness and efficiency of this method is demonstrated by the high-order harmonic spectra of one-dimensional atoms in comparison with other references.     

Pseudospectral method with symplectic algorithm for the solution of time-dependent SchrSdinger equations

A pseudospectral method with symplectic algorithm for the solution of time-dependent Schrodinger equations （TDSE） is introduced. The spatial part of the wavefunction is discretized into sparse grid by pseudospectral method and the time evolution is given in symplectic scheme. This method allows us to obtain a highly accurate and stable solution of TDSE. The effectiveness and efficiency of this method is demonstrated by the high-order harmonic spectra of one-dimensional atom in strong laser field as compared with previously published work. The influence of the additional static electric field is also investigated.     

Multiple collisions in crystal high-order harmonic generation

We theoretically investigate high-order harmonic generation (HHG) in crystals induced by linearly polarized laser fields. We obtain the HHG spectra by solving the semiconductor Bloch equations and analyze the radiation process by different models. Here we propose a multiple collision model, in which the electrons and holes are produced at different times and places. It is found that the multiple collision trajectories can help us comprehensively and better explain the results of the quantum calculation. Moreover, we find that the harmonic suppression occurs due to the overlap of multiple collision trajectories.     

A Time-Dependent Approach to High-Resolution Photoabsorption Spectrum of Rydberg Atoms in Magnetic Fields

A robust time-dependent approach to the high-resolution photoabsorption spectrum of Rydberg atoms in magnetic fields is presented. Traditionally we have to numerically diagonalize a huge matrix to solve the eigen-problem and then to obtain the spectral information. This matrix operation requires high-speed computers with large memories. Alternatively we present a unitary but very easily parallelized time-evolution method in an inexpensive way, which is very accurate and stable even in long-time scaie evolution. With this method, we perform the spectral caiculation of hydrogen atom in magnetic field, which agrees well with the experimentai observation. It can be extended to study the dynamics of Rydberg atoms in more complicated cases such as in combined electric and magnetic fields.     

Enhanced THz Radiation from Spatially Inhomogeneous Fields

Nonlinear terahertz(THz) radiation from gas media usually relies on the asymmetric laser-induced current produced by ultra-intense two-color laser fields with a specific phase delay. Here a new scheme is proposed and theoretically investigated, in which the radiation is generated by spatially inhomogeneous fields induced by relatively low-intensity monochromatic lasers and an array of single triangular metallic nanostructures. Our simulations are based on the classical photocurrent model and the...