Selective page-addressable fixing of volume holograms in Sr0.75Ba0.25Nb2O6 crystals

We demonstrate selective fixing of volume holograms in photorefractive media. Each holographic page may be fixed individually and overwritten without destroying the other fixed pages. We present experimental results describing this process in Cr-doped Sr0.75Ba0.5Nb2O6 at room temperature, with hologram lifetimes exceeding 100 days during continuous readout with an intense beam (1 W/cm^2)

Electric-field multiplexing/demultiplexing of volume holograms in photorefractive media

We propose a new method of volume hologram multiplexing/demultiplexing in noncentrosymmetric media. Volume holograms may be multiplexed by tuning the material parameters of the recording medium (such as refractive index or lattice parameters) while keeping the external parameters (wavelength and angles) fixed. For example, an external dc electric field alters the index of refraction through the electro-optic effect, effectively changing the recording and reconstruction wavelengths in the storage medium. Then the storage of holograms at different fields, hence different indices of refraction, is closely related to wavelength multiplexing. We demonstrate this concept in a preliminary experiment by electrically multiplexing two volume holograms in a strontium barium niobate crystal

Optical and electrical Barkhausen noise induced by recording ferroelectric domain holograms

Ferroelectric domain gratings with periods of the order of an optical wavelength are induced in strontium barium niobate by photorefractive space-charge fields. We measure the Barkhausen noise in current and diffraction efficiency while optically recording domain gratings and show that the two are strongly correlated in time. Significant random depolarization occurs under high-intensity illumination. We deduce the kinetics of the domain inversion process from the shape of the current transients

Vector solitons in (2+1) dimensions

We address the problem of existence and stability of vector spatial solitons formed by two incoherently interacting optical beams in bulk Kerr and saturable media. We identify families of (2+1)-dimensional two-mode self-trapped beams, with and without a topological charge, and describe their properties analytically and numerically.Comment: 3 pages, 5 figures, submitted to Opt. Let

The single-particle density matrix and the momentum distribution of dark "solitons" in a Tonks-Girardeau gas

We study the reduced single-particle density matrix (RSPDM), the momentum distribution, natural orbitals and their occupancies, of dark "soliton" (DS) states in a Tonks-Girardeau gas. DS states are specially tailored excited many-body eigenstates, which have a dark solitonic notch in their single-particle density. The momentum distribution of DS states has a characteristic shape with two sharp spikes. We find that the two spikes arise due to the high degree of correlation observed within the RSPDM between the mirror points ($x$ and $-x$) with respect to the dark notch at $x=0$; the correlations oscillate rather than decay as the points $x$ and $-x$ are being separated.Comment: 9 pages, 8 figure