Search results for "Diffraction"
showing 10 items of 1584 documents
Parallel phase-shifting digital holography based on the fractional Talbot effect
2010
A method for recording on-axis single-shot digital holograms based on the self-imaging phenomenon is reported. A simple binary two-dimensional periodic amplitude is used to codify the reference beam in a Mach-Zehnder interferometer, generating a periodic three-step phase distribution with uniform irradiance over the sensor plane by fractional Talbot effect. An image sensor records only one shot of the interference between the light field scattered by the object and the codified parallel reference beam. Images of the object are digitally reconstructed from the digital hologram through the numerical evaluation of the Fresnel diffraction integral. This scheme provides an efficient way to perfo…
Spectroscopy of exotic states of 13C
2014
The differential cross-sections of the elastic and inelastic 13C + α scattering were measured at E (α) = 65 MeV. The radii of the states: 8.86 (1/2¯), 3.09 (1/2+ ) and 9.90 (3/2¯) MeV were determined by the Modified diffraction model (MDM). The radii of the first two levels are enhanced relatively that of the ground state of 13C, confirming the suggestion that the 8.86 MeV state could be an analogue of the Hoyle state in 12C and the 3.09 MeV state has a neutron halo. No enhancement of the radius of the 9.90 MeV state was observed. peerReviewed
Grating compensated dispersion-managed systems incorporating nonlinear optical loop mirrors
2006
In this work, we investigate the use of nonlinear optical loop mirrors (NOLMs) in DM fiber systems compensated by CFGs with GDR by launching a 128-bit Gaussian-shaped pseudo-random bit sequence having pulse width of 5 ps for simulating a 40 Gb/s system. The dispersion map contains a fiber segment of length 10.3 km and a CFG with dispersion of -15.6 ps/nm. We consider a lossless grating and the GDR is modeled by a sinusoidal function for simplicity. We have shown that the use of NOLMs can substantially improve the transmission performance in a grating-compensated DM fiber system even with presence of amplifier noise and random variations of GDR, parameters in CFGs along the propagation dista…
Weak itinerant ferromagnetism and electronic and crystal structures of alkali-metal iron antimonides: NaFe4Sb12andKFe4Sb12
2004
The synthesis, chemical, structural, and magnetic properties of alkali-metal compounds with filled-skutterudite structure, $\mathrm{Na}{\mathrm{Fe}}_{4}{\mathrm{Sb}}_{12}$ and $\mathrm{K}{\mathrm{Fe}}_{4}{\mathrm{Sb}}_{12}$, are described. X-ray and neutron diffraction and elemental analysis established the crystal structure without defects and disorder on the cation site. The temperature and pressure dependence of the cubic unit cell of $\mathrm{Na}{\mathrm{Fe}}_{4}{\mathrm{Sb}}_{12}$ and the displacement parameter of Na are investigated. The electronic structure is calculated by density functional methods (LMTO, FPLO). Quantum chemical calculations (electron localization function) reveal …
Modulated magnetic structures of ErPb3, HoPb3, ErTl3 and HoTl3
1981
Neutron diffraction experiments have been carried out on the magnetically ordered phases of ErPb3, HoPb3, ErTl3 and HoTl3. The magnetic moments were found to be sinusoidally modulated with a propagation vector of (0, 0.2, 0.5) for the Pb-compounds and (0.38, 0.38, 0.16) for the Tl-compounds.
SMIM in reflection imaging mode
2019
We present reflective SMIM (initials incoming from Spatially-Multiplexed Interferometric Microscopy) as an extremely simple and low cost way to convert a standard white-light microscope into a holographic one working under reflection imaging mode.
One-dimensional error-diffusion technique adapted for binarization of rotationally symmetric pupil filters
1995
Abstract Two novel algorithms for the binarization of continuous rotationally symmetric real and positive pupil filters are presented. Both algorithms are based on the one-dimensional error diffusion concept. In our numerical experiment an original gray-tone apodizer is substituted by a set of transparent and opaque concentric annular zones. Depending on the algorithm the resulting binary mask consists of either equal width or equal area zones. The diffractive behavior of binary filters is evaluated. It is shown that the filter with equal width zones gives Fraunhofer diffraction pattern more similar to that of the original gray-tone apodizer than that with equal area zones, assuming in both…
Realization of a two-dimensional Ising system: Deuterium physisorbed on krypton-preplated graphite
2004
Volumetric adsorption isotherm, calorimetric, and neutron diffraction measurements were used to characterize the quantum system ${\mathrm{D}}_{2}$ coadsorbed on graphite preplated by a monolayer of Kr. From the results obtained by these methods a detailed phase diagram of the complete submonolayer coverage range up to the initial stages of bilayer formation could be constructed. The dominant feature of the phase diagram is a commensurate $(1\ifmmode\times\else\texttimes\fi{}1)[\frac{1}{2}]$ structure, which was determined by neutron diffraction. Three phase transitions of this phase were studied: The order-disorder transition at the critical point which, according to the influence of the co…
Second-order optical phase transition in a semilinear photorefractive oscillator with two counterpropagating pump waves
2002
Soft-mode onset of coherent oscillation is revealed in a semilinear cavity with two counterpropagating pump waves. From the dynamics of the oscillation intensity and the dynamics of the grating decay with the feedback applied, critical behavior is detected: Both the characteristic time of oscillation onset and grating decay time go to infinity exactly at the threshold coupling strength. A conclusion is made about the similarity of this type of oscillator to the second-order phase transition.
Anisotropic exchange in ErSb
1983
The correlations of the magnetic moments and the magnetic order parameter of ErSb have been studied by neutron diffraction. The antiferromagnetic phase transition is of first order. The diffuse paramagnetic scattering is evaluated in terms of magnetic coupling tensors which are characterized by a strong two-ion anisotropy.