We propose a scheme for scalable photonic quantum computation based on cavity-assisted interaction between single-photon pulses. The prototypical quantum controlled phase-flip gate between the single-photon pulses is achieved by successively reflecting them from an optical cavity with a single-trapped atom. Our proposed protocol is shown to be robust to practical noise and experimental imperfec...

We show theoretically that stimulated spin-flip Raman scattering can be used to inject spin currents in doped semiconductors with spin-split bands. A pure spin current, where oppositely oriented spins move in opposite directions, can be injected in zinc blende crystals and structures. The calculated spin current should be detectable by pump-probe optical spectroscopy and anomalous Hall effect m...

We have studied the absorption of electromagnetic radiation of an anisotropic quantum dot taking into account the spin-flip processes that is associated with the interaction of the electrons with optical phonons. It is shown that these processes lead to the resonance absorption. Explicit formula is derived for the absorption coefficient. The positions of the resonances peaks are found.

We show by means of analytical and numerical calculations that saturation, in combination with the linewidth-enhancement factor and the finite rate of spin-flip processes, causes a redshift of the spontaneous-emission peak with respect to the off-lasing-mode frequency in the optical spectrum of a quantum-well vertical-cavity surface emitting laser.

This paper presents an architecture for an all optical switching node. The architecture is suitable for optical packet and optical burst switching and provides appropriate contention resolution schemes and QoS guarantees. A concept, called virtual memory, is developed to allow controllable and reasonable periods for delaying optical traffics. Related to its implementation, several engineering i...

An optical vortex, produced at one point in an optical beam, would propagate through an optical system to another point where the vortex can be used for some purpose. However, asymmetrical optical elements in such a system can cause astigmatism or at least distroy the rotational symmetry of the beam, which may affect the propagation of the vortex in an undesirable way. While an optical vortex i...

during winter 2004 and 2005, two field and glasshouse experiments were conducted to evaluate the response of 471 chickpea genotypes to ascochyta rabiei, as ascochyta blight (ab) disease in chickpea (cicer aurietimum). frequent rainfall at flowering and pod formation stages made favorite conditions conducive for the infection and symptoms expression. so, the genotypes with high level of toleranc...

We discuss the effects of imperfect photon detectors suffering from loss and noise on the reliability of linear optical quantum computers. We show that for a given detector efficiency, there is a maximum achievable success probability, and that increasing the number of ancillary photons and detectors used for one controlled sign flip gate beyond a critical point will decrease the probability th...

Passive fiber ring resonators synchronously pumped by cw trains of ultrashort pulses are shown to exhibit polarization symmetry breaking. Application of this feature to all-optical storage is considered. The proposed storage device operates in the flip-flop mode which makes possible all-optical writing and erasing operations on individual bits. Numerical simulations suggest that a storage capac...