375 research outputs found
Squeezed-light source for the superresolving microscopy
We propose a source of multimode squeezed light that can be used for the
superresolving microscopy beyond the standard quantum limit. This source is an
optical parametric amplifier with a properly chosen diaphragm on its output and
a Fourier lens. We demonstrate that such an arrangement produces squeezed
prolate spheroidal waves which are the eigen modes of the optical imaging
scheme used in microscopy. The degree of squeezing and the number of spatial
modes in illuminating light, necessary for the effective object field
reconstruction, are evaluatedComment: 6 pages, 1 figure, RevTeX4. Shortened version will appear in Optics
Letter
Quantum teleportation of optical images with frequency conversion
We describe a new version of continuous variables quantum holographic
teleportation of optical images. Unlike the previously proposed scheme, it is
based on the continuous variables quantum entanglement between the light fields
of different frequencies and allows for the wavelength conversion between the
original and the teleported images. The frequency tunable holographic
teleportation protocol can be used as a part of light-matter interface in
parallel quantum information processing and parallel quantum memoryComment: 4 pages, 3 Postscript figures, RevTeX
Quantum parallel dense coding of optical images
We propose quantum dense coding protocol for optical images. This protocol
extends the earlier proposed dense coding scheme for continuous variables
[S.L.Braunstein and H.J.Kimble, Phys.Rev.A 61, 042302 (2000)] to an essentially
multimode in space and time optical quantum communication channel. This new
scheme allows, in particular, for parallel dense coding of non-stationary
optical images. Similar to some other quantum dense coding protocols, our
scheme exploits the possibility of sending a classical message through only one
of the two entangled spatially-multimode beams, using the other one as a
reference system. We evaluate the Shannon mutual information for our protocol
and find that it is superior to the standard quantum limit. Finally, we show
how to optimize the performance of our scheme as a function of the
spatio-temporal parameters of the multimode entangled light and of the input
images.Comment: 15 pages, 4 figures, RevTeX4. Submitted to the Special Issue on
Quantum Imaging in Journal of Modern Optic
Peculiarities of charged particle kinetics in spherical plasma
We describe kinetic simulations of transient problems in partially ionized
weakly-collisional plasma around spherical bodies absorbing or emitting charged
particles. Numerical solutions of kinetic equations for electrons and ions in
1D2V phase space are coupled to an electrostatic solver using the Poisson
equation or quasineutrality condition for small Debye lengths. The formation of
particle groups and their contributions to electric current flow and screening
of charged bodies by plasma are discussed for applications to Langmuir probes
and solar wind
Quantum memory for images - a quantum hologram
Matter-light quantum interface and quantum memory for light are important
ingredients of quantum information protocols, such as quantum networks,
distributed quantum computation, etc. In this Letter we present a spatially
multimode scheme for quantum memory for light, which we call a quantum
hologram. Our approach uses a multi-atom ensemble which has been shown to be
efficient for a single spatial mode quantum memory. Due to the multi-atom
nature of the ensemble it is capable of storing many spatial modes, a feature
critical for the present proposal. A quantum hologram has a higher storage
capacity compared to a classical hologram, and is capable of storing quantum
features of an image, such as multimode superposition and entangled quantum
states, something that a standard hologram is unable to achieve. Due to optical
parallelism, the information capacity of the quantum hologram will obviously
exceed that of a single-mode scheme.Comment: 5 pages, 3 figure
Nanostructuring of solid surfaces by femtosecond laser pulses
One-dimensional quasi-periodic structures whose period is much smaller than the wavelength of exciting optical radiation have been obtained on a titanium surface under the multi-shot action of linearly polarized femtosecond laser radiation at various surface energy densities. As the radiation energy density increases, the one-dimensional surface nanogratings oriented perpendicularly to the radiation polarization evolve from quasi-periodic ablative nanogrooves to regular lattices with sub-wavelength periods (90-400 nmyesRussian Academy of Science
Study of the evolution of the Cu/Nb interphase boundary by the molecular dynamics method
The evolution of atomic structure of the interphase boundary for composites from immiscible Cu/Nb elements is studied by the molecular dynamics method. It is established that the planar interphase boundary is stable at temperatures up to 1200 K. Atomic dissolution of elements is not revealed in the entire examined temperature interval, and the components are mixed on the interphase boundary of finite curvature in the form of clusters and nanolamellas; moreover, the amorphous state is not formed in the process of migration of the interphase boundaryyesBelgorod State Universit
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