Results 1 - 10 of 2396
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[en] We have performed a theoretical study on the case of reflection-type one-dimensional magnetophotonic crystals (MPCs) to establish a practical magneto-optical isolator (MOI). We have introduced thin MPC structures with concurrent high reflectance and large Kerr rotation for oblique incidence, and with the capability of being adjusted to perfect MOIs. It has been shown that the adjustment technique can also provide a framework for establishment of MPCs which are stable against fabrication and setup errors. - Highlights: • Introducing high performance MPCs with high reflectance and large Kerr rotation. • Introducing adjustable reflection-type magneto-optical isolators (MOIs). • The stability of the MOIs against the construction errors has been demonstrated. • The introduced MOIs operate in a wide range of incident angle
[en] We propose a scheme for preparing optical Schroedinger-cat states in a traveling wave setting. Two states are similarly prepared via the self-Kerr effect, and after mixing them, one mode is measured by homodyne detection. In the other mode, a superposition of coherent states is conditionally prepared. The advantage of the scheme is that assuming a small Kerr effect, one can prepare with a high probability one of a set of Schroedinger-cat states. The measured value of the quadrature provides information about which one of the set of states is actually prepared.
[en] We examine the robustness of ultrashort optical vortices propagating freely in the atmosphere. We first approximate the stability regions of femtosecond spinning pulses as a function of their topological charge. Next, we numerically demonstrate that atmospheric optical vortices are capable of conveying high power levels in air over hundreds of meters before they break up into filaments
[en] The effect of pressure and laser power on the high-resolution spectra of commonly available gases is studied with the help of the optically heterodyne Raman-induced Kerr effect (OHD-RIKE). The results show the expected pressure dependence of the spectra, but the effects of saturating laser power are different from previous similar studies employing other four-wave mixing techniques. In OHD-RIKE no observable sign of saturation such as power broadening, saturation dips in the line center, or deviation from a linear dependence of the signal strength with laser intensity was observed for several orders of magnitude greater intensities than previously reported for the saturation intensities in coherent anti-Stokes Raman spectroscopy (CARS). Saturation is therefore not the ultimate limit of sensitivity for OHD-RIKE. This may be an advantage of RIKE in comparison to other coherent Raman techniques. copyright 1999 The American Physical Society
[en] We study the quasiclassical dynamics of the cross-Kerr effect. In this approximation, the typical periodical revivals of the decorrelation between the two polarization modes disappear and remain entangled. By mapping the dynamics onto the Poincaré space, we find simple conditions for polarization squeezing. When dissipation is taken into account, the shape of the states in such a space is not considerably modified, but their size is reduced. (paper)
[en] A theorem related to the Newman-Penrose constants is proven. The theorem states that all the Newman-Penrose constants of asymptotically flat, stationary, asymptotically algebraically special electrovacuum space-times are zero. Straightforward application of this theorem shows that all the Newman-Penrose constants of the Kerr-Newman space-time must vanish.
[en] Here, we present polar Kerr effect measurements of the filled skutterudite superconductor PrOs4Sb12. Simultaneous ac susceptibility measurements allow us to observe the superconducting transition under the influence of heating from the optical beam. A nonzero Kerr angle θK develops below the superconducting transition, saturating at ~300 nrad at low temperatures. This result is repeated across several measurements of multiple samples. By extrapolating the measured θK(T) to zero optical power, we are able to show that the Kerr angle onset temperature in one set of measurements is consistent with the transition to the B phase at TC2. We discuss the possible explanations for this result and its impact on the understanding of multiphase and inhomogeneous superconductivity in PrOs4Sb12.
[en] The focusing and self-healing characteristics of Airy array beams propagating in self-focusing media are studied numerically. When the Kerr effect is strong enough, an Airy array beam may focus twice for the coherent combination, while an Airy array beam may not focus for the incoherent combination. These behaviors are quite different from those without Kerr effect. With and without Kerr effect, the self-healing of Airy array beams with main lobes blocked can be achieved. Furthermore, a better reconstruction for the incoherent combination case can be achieved than that for the coherent combination case. The propagation distance required for the reconstruction of Airy array beams with main lobes blocked decreases due to the Kerr effect. The reconstruction of an Airy array beam with main lobes blocked may complete before or after focusing, which depends on the intensity distribution and the coherence of the array beam and is independent of the Kerr effect.
[en] In the classical approach giant magnetoimpedance (GMI) is driven by the transverse permeability of the sample, as excited by the current flowing through it. Transverse permeability is usually taken as a constant, while detailed magnetization processes are important for the interpretation of GMI data. In most cases the transverse permeability (or magnetization) is only guessed by looking at the longitudinal magnetization curve and direct determinations of such parameter are scarce in the literature. In this work we report on the operation of a simple setup which provides the transverse magnetization of amorphous ribbons as a function of the current intensity flowing through it, by means of the magnetooptical kerr effect (MOKE). The system has been tested on low magnetostriction amorphous ribbons of very soft character with both longitudinal and transverse anisotropy. The transverse magnetization as a function of both the current and a DC longitudinal field applied, was compared with magneto impedance measurements