Spatially strongly confined atomic excitation via a two dimensional stimulated Raman adiabatic passage.

We consider a method of sub-wavelength superlocalization and patterning of atomic matter waves via a two dimensional stimulated Raman adiabatic passage (2D STIRAP) process. An atom initially prepared in its ground level interacts with a doughnut-shaped optical vortex pump beam and a traveling wave Stokes laser beam with a constant (top-hat) intensity profile in space. The beams are sent in a counter-intuitive temporal sequence, in which the Stokes pulse precedes the pump pulse.

Azimuthal modulation of electromagnetically induced grating using structured light.

We propose a theoretical scheme for creating a two-dimensional Electromagnetically Induced Grating in a three-level [Formula: see text]-type atomic system interacting with a weak probe field and two simultaneous position-dependent coupling fields-a two dimensional standing wave and an optical vortex beam. Upon derivation of the Maxwell wave equation, describing the dynamic response of the probe light in the atomic medium, we perform numerical calculations of the amplitude, phase modulations and Fraunhofer diffraction pattern of the probe field under different system parameters. We show that due to the azimuthal modulation of the Laguerre-Gaussian field, a two-dimensional asymmetric grating is observed, giving an increase of the zeroth and high orders of diffraction, thus transferring the probe energy to the high orders of direction.

Ferris wheel patterning of Rydberg atoms using electromagnetically induced transparency with optical vortex fields.

We study the formation of spatially dependent electromagnetically induced transparency (EIT) patterns from pairs of Laguerre-Gauss (LG) modes in an ensemble of cold interacting Rydberg atoms. The EIT patterns can be generated when two-photon detuning does not compensate for the Rydberg level energy shift induced by van der Waals interaction. Depending on the topological numbers of each LG mode, we can pattern dark and bright Ferris-wheel-like structures in the absorption profile with tunable barriers between sites, providing confinement of Rydberg atoms in transverse direction while rendering them transparent to light at specific angular positions.

Ultimate conversion efficiency bound for the forward double-Λ atom-light coupling scheme.

We show that for the two widely used configurations of the double- atom-light coupling scheme, one where the control fields are applied in the same -subsystem and another where they are applied in different -subsystems, the forward propagation of the probe and signal fields is described by the same set of equations. We then use optimal control theory to find the spatially dependent optimal control fields that maximize the conversion efficiency from the probe to the signal field, for a given optical density. This work can find application in the implementation of efficient frequency and orbital angular momentum conversion devices for quantum information processing, as well as to be useful for many other applications using the double- atom-light coupling scheme.

Optically induced diffraction gratings based on periodic modulation of linear and nonlinear effects for atom-light coupling quantum systems near plasmonic nanostructures.

We investigate the quantum linear and nonlinear effects in a novel five-level quantum system placed near a plasmonic nanostructure. Such a quantum scheme contains a double-V-type subsystem interacting with a weak probe field. The double-V-subsystem is then coupled to an excited state by a strong coupling field, which can be a position-dependent standing-wave field.

Strongly confined atomic localization by Rydberg coherent population trapping.

We investigate the possibility to attain strongly confined atomic localization using interacting Rydberg atoms in a coherent population trapping ladder configuration, where a standing-wave is used as a coupling field in the second leg of the ladder. Depending on the degree of compensation for the Rydberg level energy shift induced by the van der Waals interaction, by the coupling field detuning, we distinguish between two antiblockade regimes, i.e.

Tunneling induced two-dimensional phase grating in a quantum well nanostructure via third and fifth orders of susceptibility.

We study the nonlinear optical properties in an asymmetric double AlGaAs/GaAs quantum well nanostructure by using an external control field and resonant tunneling effects. It is found that the resonant tunneling can modulate the third-order and fifth-order of susceptibilities via detuning frequency of coupling light. In presence of the resonant tunneling and when the coupling light is in resonance with the corresponding transition, the real parts of third-order and fifth-order susceptibilities are enhanced which are accompanied by nonlinear absorption.

Azimuthal modulation of electromagnetically induced transparency using structured light.

Recently a scheme has been proposed for detection of the structured light by measuring the transmission of a vortex beam through a cloud of cold rubidium atoms with energy levels of the Λ-type configuration [N. Radwell et al., Phys.

Enhancement of Goos-Hänchen shift due to a Rydberg state.

This paper hints at the Goos-Hänchen shift properties of a cavity containing an ensemble of atoms using a four-level atomic system involving a Rydberg state. By means of the stationary phase theory and density matrix formalism in quantum optics, we study theoretically the Goos-Hänchen shifts in both reflected and transmitted light beams. It is realized that as a result of the interaction between Rydberg and excited states in such a four-level atom-light coupling scheme the maximum positive and negative Goos-Hänchen shifts can be obtained in reflected and transmitted light beams owning to the effect of the Rydberg electromagnetically induced transparency (EIT) or Rydberg electromagnetically induced absorption.

Optical bistability and multistability via magnetic field intensities in a solid.

Optical bistability (OB) and optical multistability (OM) behavior in molecular magnets is theoretically studied. It is demonstrated that the OB of the system can be controlled via adjusting the magnetic field intensity. In addition, it is shown that the frequency detuning of probe and coupling fields, as well as the cooperation parameter, has remarkable effects on the OB behavior of the system.