Laser Eld Research Articles

Analysis of the process e+e- → h0a0 in ihdm in the presence of a linearly polarized laser field

We consider the process of neutral Higgs production from e+e- annihilation in Inert Higgs Doublet Model (IHDM) in the absence and presence of an external eld. The latter is assumed to be a plane and monochro-matic wave with linear polarization. In the theoretical framework, we present the analytic calculation of the lowest order di erential cross section by using the scattering matrix approach and Dirac-Volkov formalism for charged incident particles. The total cross section is computed by performing a numerical integration of the di erential cross section over the solid angle. The results obtained are analyzed and discussed for di erent centre of mass energies and laser parameters. We found that inserting a laser wave with linear polarization is a suitable mechanism to enhance the total cross-section of the process. Indeed, the probability of the process to occur increases with the presence of a linearly polarized laser eld, especially with low frequency and high strength.

Orientation-dependent transition rule in high-order harmonic generation from solids

We study the role of transition rule in high-order harmonic generation from solids driven by linearly polarized laser elds. The orientation-dependent transition dipoles can regulate the emergence of the multi-plateau structure. In the multi-plateau zone, however, di erent from the mechanisms of step-by-step excitation reported previously, we nd that the emission time and orientationdependent yields exhibit synchronization and more ne patterns, respectively. And the orientationdependent yields and its ne patterns can be attributed to the collective contribution of the transition rule and quantum-path interference. Therefore, to better understand the constructive and destructive patterns in the orientation-dependent yields, we propose a scheme of intercycle interference, which can further be utilized as a tool to image the structure of the solids and provide an avenue to optimize the electron dynamics in solids for the production of attosecond pulses in a compact setup.

Tight-Binding Models in a Quasiperiodic Optical Lattice

This paper describes how one can use four standing wave laser elds to realize a two dimensional optical quasicrystal with eight-fold symmetry, closely related to the well-known octagonal or Ammann-Beenker tiling quasicrystal. We describe the structure and we outline the main features of an e ective tight-binding model for atoms in this optical quasicrystal. Such a system, if realized experimentally, should provide valuable insights into the quantum properties of quasicrystals.

Resonant Tunneling Controlled by Laser and Constant Electric Fields

The aim of this paper is to present a numerically stable algorithm for investigations of nonrelativistic quantum processes occurring in arbitrary space-dependent scalar potential and a timeand space-dependent vector potential. Vector potential is periodic in time and describes a laser eld. Such conditions are met for example in semiconductor nanostructures [1 8] (like quantum wires or wells), photoemission from a metal tip [9], carbon nanotubes [10, 11] or in surface physics [12 16]. To make our presentation as clear as possible we shall restrict ourselves to the one-space-dimensional case, although extension of this algorithm to two and three-space dimensional systems, also with magnetic eld accounted for, is possible (see, e.g. [17]). We shall apply our method to investigation of the tunneling process and its dependence on relative phases of multichromatic laser pulses (multicolor processes have been considered for instance in [16, 18]). Multiple barrier, eld-assisted resonant tunneling is an interesting problem because it provides an insight into the physics of nanostructure quantum systems and because it is a fundamental e ect to use in a wide variety of technological applications. As concerns the latter, it is enough to mention all sorts of detectors and generators of microwave radiation based on double barrier structures with external electric eld added; for more examples, see [19 24]. Here we analyze resonant tunneling through semiconductor structures in the presence of both oscillating and constant in time external electric elds. The elds are supposed to be nonperturbative. We assume that single-

Manifestation of the optical Stark effect in differential transmission spectra

The two-level quantum system is applied in theoretical modelling of the angle-resolved differential absorption spectra induced by the strong near-resonant laser eld in quantum dots. The simulations of induced polarization waves at appropriate directions have been performed by means of the density matrix formalism, without using perturbation theory. An interpretation of the differential spectra is provided referring to representation of the dressed states, with their energies experiencing Stark shifts due to the action of the laser eld. The feasibility of the light and matter interaction strength characterization via observed Mollow spectrum at the different (from the probe beam) direction is demonstrated.

Multielectron response to intense laser fields

In this paper we will describe recent theoretical approaches to calculating the response of multielectronic atoms in intense laser elds. This work is based on the soultion of the time-dependent Schrodinger equation for a single atom driven by a lin- early polarized laser eld. Results obtained in recent experimental measurements of multiple ionization rates suggest that the interaction between the electrons in heli- um enhances the double ionization rate. Solving the full two-electron Schrodinger equation is a very computer-intensive problem, and therefore we have introduced a new model that can reproduce the experimental results. This model is described in detail in this paper, and used to investigate the origin of the double ionization.