In this paper we investigate the squeezing of a finite-bandwidth optical field which may be thought of as originating from Einstein-Podolsky-Rosen-(EPR-) like quantum correlations between the upper and lower sidebands. Ordinarily, when EPR pairs are created from such a resource, the bandwidth is preserved, and the signal-to-noise ratio of the quadrature correlations is reduced. Here we show that by using frequencydependent beam splitters we may create N EPR pairs from a single finite-bandwidth squeezed beam with no reduction in the correlations's signal-to-noise ratio. However, the bandwidth is reduced by a factor of N relative to the original squeezed beam. Because this transformation is linear it may be inverted to retrieve the single squeezed beam from the corresponding N EPR pairs.

In this paper we present a scheme in which the amplitude-quadrature difference and phase-quadrature difference of two bright nonclassical beams serve as a pair of observed complementary variables that can be measured directly and can form a new squeezed state. Mixing such two quadrature-difference squeezed-state beams on a beam splitter produces characteristic of the Einstein-Podolsky-Rosen quantum entanglement. The experimental schemes producing such nonclassical beams and its possible applications in quantum information are discussed.

Highly efficient quantum dense coding for continuous variables has been experimentally accomplished by means of exploiting a bright Einstein-Podolsky-Rosen (EPR) beam with anticorrelation of amplitude quadratures and correlation of phase quadratures. Two bits of classical information are encoded on two quadratures of a half of a bright EPR beam, then are simultaneously decoded by the other half of the EPR beam with the sensitivities beyond that of the shot noise limit. A high degree of immunity to unauthorized eavesdropping has been experimentally demonstrated.

We investigate the different characteristics of the intensity noise of a laser-diode-pumped single-frequency Vring Nd: YVO4 laser and a Nd: YVO4 KTP green laser. By use of an optoelectronic feedback circuit connected directly to the pump current of the laser diode, the low-frequency intensity noise of the intracavity frequency doubler was suppressed to some extent.

We report the observation of three p-wave Feshbach resonances of 6Li atoms in the lowest hyperfine state f=1/2. The positions of the resonances are in good agreement with theory. We study the lifetime of the cloud in the vicinity of the Feshbach resonances and show that, depending on the spin states, two-or three-body mechanisms are at play. In the case of dipolar losses, we observe a nontrivial temperature dependence that is well explained by a simple model.