Controlling laser spectra in a phaseonium photonic crystal using maser

We study the control of quantum resonances in photonic crystals with electromagnetically induced transparency driven by microwave field. In addition to the control laser, the intensity and phase of the maser can alter the transmission and reflection spectra in interesting ways, producing hyperfine resonances through the combined effects of multiple scattering in the superstructure.Comment: 7 pages, 4 figure

Rotational Cooling of Polar Molecules by Stark-tuned Cavity Resonance

A general scheme for rotational cooling of diatomic heteronuclear molecules is proposed. It uses a superconducting microwave cavity to enhance the spontaneous decay via Purcell effect. Rotational cooling can be induced by sequentially tuning each rotational transition to cavity resonance, starting from the highest transition level to the lowest using an electric field. Electrostatic multipoles can be used to provide large confinement volume with essentially homogeneous background electric field.Comment: 10 pages, 6 figure

Casimir force control with optical Kerr effect

The control of the Casimir force between two parallel plates can be achieved through inducing the optical Kerr effect of a nonlinear material. By considering a two-plate system which consists of a dispersive metamaterial and a nonlinear material, we show that the Casimir force between the plates can be switched between attractive and repulsive Casimir force by varying the intensity of a laser pulse. The switching sensitivity increases as the separation between plate decreases, thus providing new possibilities of controlling Casimir force for nanoelectromechanical systems

Atom and quantum oscillator coupled by the vacuum field: Radiation pattern, emission spectrum, and decay dynamics

We study the dynamics of a system consisting of a two-level atom and a quantum oscillator coupled by the vacuum radiation field. The oscillator and the atom are assumed to have the same resonance frequency. In contrast to the two-atom or two-oscillator case, the atom-oscillator system leads to an unclosed hierarchy of equations for the operators that determine the radiation pattern emitted by the atom-oscillator system. Instead of using the operator equations, we formulate the problem in terms of density-matrix equations which can be solved once the initial conditions are specified. As an example, we looked at the radiation pattern, the decay dynamics, and the spectrum for an initial condition in which the oscillator is in its n=1 state and the atom is in its excited state. Dressed states (dressed by the static interaction between the atom and oscillator) prove to be especially useful for interpreting the results and comparing them with the two-atom and two-oscillator systems. All calculations are carried out using the resonance or rotating-wave approximation. The relationship of our work to damped Jaynes-Cummings models is noted

Echo and ringing of optical pulse in finite photonic crystal with superconductor and dispersive dielectric

We study the transient pulse propagation in one-dimensional photonic crystal. Two new effects are identified: double reflection and slow-light ringing of transmitted and reflected pulses. We analyze these effects in superconductor-dielectric photonic crystal around the polariton resonance region of the dielectric material. Distinct double-polariton dispersions and narrow peaks in the transmission and reflection spectra are found when the plasma gap and the polariton gap of the dielectric overlap. Potential applications of these effect are discussed. (C) 2010 Optical Society of Americ

Spin–orbital angular momentum coupling in Bose–Einstein condensate and its spin dynamics

We examine the use of Laguerre–Gaussian (LG) laser beams in the tripod scheme to create the coupling between spin and orbital angular momentum in a Bose–Einstein condensate (BEC) confined by a harmonic trap. We derive and solve the Gross–Pitaevskii equation numerically to obtain the density distribution of the BEC. Orbital angular momentum from the LG beam is transferred to the BEC, inducing the formation of a giant vortex at the BEC’s centre. The macroscopic flow of spinor BEC around the vortex leads to a persistent spin current in the BEC

Controlling quantum resonances in photonic crystals and thin films with electromagnetically induced transparency

Quantum coherence or phaseonium medium with electromagnetic-induced transparency (EIT) may have been widely explored, but the incorporation of boundaries into finite structures like thin films and photonic crystals introduce additional resonant features. A narrow transmission peak exists in resonant medium due to multiple reflections and interference. The corresponding analytical formulas for absorptive and EIT media are derived. A double dip feature is found only for transverse magnetic polarized light, due to longitudinal electric field component in a Fabry-Perot thin film. We study these resonant features in a finite superlattice and discuss potential applications of the features. For phaseonium medium with laser-driven gain, transmission and reflection peaks beyond unity appear between the two EIT resonances. Realizations using solid-state materials such as doped crystals and quantum dots with potential applications are discussed

Probing infinity in bounded two-dimensional electrostatic systems

The total electrostatic energy of systems of identical particles of equal charge is studied in configurations bounded in space, but divergent in the number of charges. This approach shall guide us to unveil a non-linear, functional form specifying the divergent nature of system energy. We consider fractals to be physical entities, with charges located in their vertices or nodes. This description is interesting since features, such as the corresponding fractal dimension, can characterize the total energy EN. Finally, at local length scales, we describe how energy diverges at charge accumulation points in the fractal, that is, almost everywhere by definition

Spatial-temporal dynamics of stimulated Raman scattering: Effects of populations and two-photon detuning

A quantum theory of stimulated Raman scattering is established that takes into account the time-dependence of pump laser pulse, two-photon detuning and atomic populations, allowing the general transient and spatial propagation study of Raman memory. Heisenberg–Langevin and Maxwell equations for the collective atomic operators are solved analytically under adiabatic condition, where the electric field envelopes and the collective atomic operators vary slowly. The analytical solution of Stokes/anti-Stokes signal electric field operator is obtained. The spatial–temporal intensity of quantum signal field is studied numerically and analytically for different two-photon detunings and initial populations