248 research outputs found

    Nanostructuring of solid surfaces by femtosecond laser pulses

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    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

    Systematic analysis of SNR in bipartite Ghost Imaging with classical and quantum light

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    We present a complete and exhaustive theory of signal-to-noise-ratio in bipartite ghost imaging with classical (thermal) and quantum (twin beams) light. The theory is compared with experiment for both twin beams and thermal light in a certain regime of interest

    Characteristics of the electric field accompanying a longitudinal acoustic wave in a metal. Anomaly in the superconducting phase

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    The temperature dependence of the amplitude and phase of the electric potential arising at a plane boundary of a conductor when a longitudinal acoustic wave is incident normally on it is investigated theoretically and experimentally. The surface potential is formed by two contributions, one of which is spatially periodic inside the sample, with the period of the acoustic field; the second is aperiodic and arises as a result of an additional nonuniformity of the electron distribution in a surface layer of the metal. In the nonlocal region the second contribution is dominant. The phases of these contributions are shifted by approximately \pi /2. For metals in the normal state the experiment is in qualitative agreement with the theory. The superconducting transition is accompanied by catastrophically rapid vanishing of the electric potential, in sharp contrast to the theoretical estimates, which predict behavior similar to the BCS dependence of the attenuation coefficient for a longitudinal sound.Comment: 9 pages, 6 figure

    Entangled-State Lithography: Tailoring any Pattern with a Single State

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    We demonstrate a systematic approach to Heisenberg-limited lithographic image formation using four-mode reciprocal binominal states. By controlling the exposure pattern with a simple bank of birefringent plates, any pixel pattern on a (N+1)×(N+1)(N+1) \times (N+1) grid, occupying a square with the side half a wavelength long, can be generated from a 2N2 N-photon state.Comment: 4 pages, 4 figure

    Femtosecond laser writing of subwave one-dimensional quasiperiodic nanostructures on a titanium surface

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    One-dimensional quasiperiodic structures whose period is much smaller than the wavelength of exciting radiation have been obtained on a titanium surface under the multipulse action of linearly polarized femtosecond laser radiation with various surface energy densitiesye

    Surface modification of titanium by pulsed laser radiation of femtosecond duration

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    The effect of an infrared pulse laser with femtosecond radiation (λ = 744 nm, τ ≈ 120 fs, E ≤ 8 mJ) on the surface of Ti of commercially purity in the submicrocrystalline state is investigated using scanning electron microscopy (SEM)yesBelgorod State Universit

    Structure and diffusion processes in laminated composites of a Cu-Ti system

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    Characteristics of diffusion transformations in a multi-layer composite of a Cu-Ti system, which was produced by high-temperature diffusion welding followed by rolling at room temperature, are reportedye
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