A quantum volume hologram

We propose a new scheme for parallel spatially multimode quantum memory for light. The scheme is based on counter-propagating quantum signal wave and strong classical reference wave, like in a classical volume hologram, and therefore can be called a quantum volume hologram. The medium for the hologram consists of a spatially extended ensemble of atoms placed in a magnetic field. The write-in and read-out of this quantum hologram is as simple as that of its classical counterpart and consists of a single pass illumination. In addition we show that the present scheme for a quantum hologram is less sensitive to diffraction and therefore is capable of achieving higher density of storage of spatial modes as compared to previous proposals. A quantum hologram capable of storing entangled images can become an important ingredient in quantum information processing and quantum imaging.Comment: 8 pages, 2 figure

Cathodoluminescence read-out of the structural phase of gallium nanoparticles

We report on a method of phase identification of gallium nanoparticles via their cathodoluminescence when excited by a scanning electron beam. This feature can be used for high-density phase change memory element

Cathodoluminescence and phase-change functionality of metallic nanoparticles

Nanoscale resolution cathodoluminescence (CL) has been used to demonstrate and investigate the functionality of nanoparticle-based components for future nanophotonic phase-change memory and optical antenna applications. An integrated experimental system based on a scanning electron microscope was developed for the fabrication and in situ characterization of nanoparticles. It was equipped with an atomic beam source for gallium nanoparticle growth, a liquid-nitrogen-cooled cryostat to control substrate temperature in the range from 90 to 315 K and a spectroscopic CL detection system to enable the analysis of electron-beam-induced light emission from nanoparticles across the wavelength range from 350 to 1150 nm. A new technique of light-assisted, size-controlled growth of gallium nanoparticles from an atomic beam has been developed. Through coupling to surface plasmons in nanoparticles, infrared radiation controls the adsorption/desorption rate of gallium atoms on the particles' surface. The experiments revealed a decrease in mean particle diameter (from 68 to 45 nm) with increasing infrared excitation intensity (from 160 to 630 W·cm-2) during deposition, and the production of larger particles with a narrower size distribution for longer deposition times. Gallium nanoparticle phase-change memory provides an important possibility to achieve small element size and low energy consumption. For the first time, it has been shown that information can be written into the structural phase of bistable gallium nanoparticles by electron beam excitation and readout achieved via measurements of their CL emission. Change of up to 20 % in CL emission intensity was observed following low fluence (> 35 fJ/nm2) electron-beam-induced, solid-to-liquid phase switching of a monolayer of 60 nm particles. Selective electron beam addressing and CL readout of individual memory elements (comprising less than 50 particles each), within a gallium nanoparticle film, have been also demonstrated. Numerical modeling of CL emission from gallium nanoparticles, performed using the boundary element method, qualitatively reproduces the experimentally observed effects. Optical antennae are expected to become essential elements of future nanophotonic circuits. For the first time, it has been demonstrated that electron-beam-excited pairs of coupled gold nanorods can act as transmitting optical antennae; i.e. they can efficiently convert the energy from a nanoscale excitation (created by a focused 40 keV electron beam) into far-field visible radiation. Enhanced light emission was observed for electron beam injection points in the vicinity of the junction between coupled nanorods, illustrating the increased local density of electromagnetic states in such areas

Optical size control in growth of gallium nanoparticles

We report that a low level of optical excitation provides a substantial influence on the size distribution of gallium nanoparticles grown from the atomic beam on a cryogenic substrate, thus providing a new way of achieving tailored films of nanoparticles with given characteristics. The growth experiments, performed in situ in the vacuum chamber of a scanning electron microscope (SEM) equipped with an inverted effusion cell, revealed that the median diameter of the nanoparticles decreases with increasing irradiating optical power, with 0.1, 0.2 and 0.4 mW average power resulting in 70, 50 and 45 nm particles, respectively

Phase-change memory functionality in gallium nanoparticles

We report that the structural phase of gallium nanoparticles can be switched by optical excitation and read via their cathodoluminescence (CL) when excited by a scanning electron beam. This opens a new paradigm in developing high-density phase change optical memory elements. A film of gallium nanoparticles was sputtered at the end face of an optical fiber, through which the reflectivity at 195 K was monitored by a 1.31 µm laser. By launching a single pulse from a 1.55 µm laser (17 mW, 1 µs) to the sample, a solid-to-liquid phase transition was observed as an immediate change of reflectivity from 10.0 to 10.5 %. CL spectra were measured immediately before and after the phase transition. The spectra show that gallium nanoparticles luminesce in the range of 400-650 nm, in which there at 520 nm is a 10 % difference of emission before and after the phase transition, due to a difference in optical properties. In future continuation of this first demonstration of electron beam read-out of the phase of nanoparticles, it is likely that the electron beam itself can change the phase of individual nanoparticles in the film, and that this phase furthermore can be read out at lower power by its cathode luminescence response with the same electron beam

Expression of Recombinant Proteins in Bacteria for Antibody Production

The protozoan parasite Trypanosoma brucei causes fatal African trypanosomiasis in humans and nagana in cattle. Transmitted by the tsetse fly, T. brucei proliferates in the bloodstream of its mammalian host and evades the host\u27s immune response by regularly switching its major surface antigen, VSG, which forms a thick coat on its cell membrane. VSGs are exclusively expressed from sub-telomeric regions of the T. brucei genome in a strictly monoallelic fashion. Telomeres, DNA-protein complexes located at chromosome ends, help maintain chromosome stability and integrity. We have also found that telomere proteins are important for regulating VSG expression and switching. We are currently studying functions of telomere proteins in antigenic variation. Antibodies against several proteins including a novel telomere protein, Tb1710, the catalytic subunit of telomerase, TbTERT, and a DNA recombination protein involved in DNA damage repair, TbRAD51, are important reagents enabling us to detect these molecules using molecular approaches. We therefore aim to express recombinant proteins in bacteria and raise customized antibodies that specifically recognize these proteins. We have made all expression constructs for these recombinant proteins and are currently purifying these proteins.https://engagedscholarship.csuohio.edu/u_poster_2016/1009/thumbnail.jp

Expression of Recombinant Proteins in Bacteria for Antibody Production

The protozoan parasite Trypanosoma brucei causes fatal African trypanosomiasis in humans and nagana in cattle. Transmitted by the tsetse fly, T. brucei proliferates in the bloodstream of its mammalian host and evades the host\u27s immune response by regularly switching its major surface antigen, VSG, which forms a thick coat on its cell membrane. VSGs are exclusively expressed from sub-telomeric regions of the T. brucei genome in a strictly monoallelic fashion. Telomeres, DNA-protein complexes located at chromosome ends, help maintain chromosome stability and integrity. We have also found that telomere proteins are important for regulating VSG expression and switching. We are currently studying functions of telomere proteins in antigenic variation. Antibodies against several proteins including a novel telomere protein, Tb1710, the catalytic subunit of telomerase, TbTERT, and a DNA recombination protein involved in DNA damage repair, TbRAD51, are important reagents enabling us to detect these molecules using molecular approaches. We therefore aim to express recombinant proteins in bacteria and raise customized antibodies that specifically recognize these proteins. We have made all expression constructs for these recombinant proteins and are currently purifying these proteins.https://engagedscholarship.csuohio.edu/u_poster_2016/1009/thumbnail.jp

Observation of asymmetric spectrum broadening induced by silver nanoparticles in a heavy-metal oxide glass

We demonstrate experimentally and support by a theoretical analysis an effect of asymmetric spectrum broadening, which results from doping of silver nanoparticles into a heavy-glass matrix, 90(0.5WO3-0.3SbPO4-0.2PbO)-10AgCl. The strong dispersion of the effective nonlinear coefficient of the composite significantly influences the spectral broadening via the self-phase modulation, and leads to a blue upshift of the spectrum. Further extension of the spectrum towards shorter wavelengths is suppressed by a growing loss caused by the plasmon resonance in the silver particles. The red-edge spectral broadening is dominated by the stimulated Raman Scattering.Comment: Accepted for publishing epl13477; EPL Journal 201