We have combined two high transmission planar x-ray waveguides glued onto each other in a crossed geometry to form an effective quasi-point source. From measurements of the far-field diffraction pattern, the phase and amplitude of the near-field distribution is retrieved using the error-reduction algorithm. In agreement with finite difference field simulations (forward calculation), the reconst...

We show the both amplitude and spectrum dynamics of few-cycle laser pulses in two-photon Raman-type self-induced transparency in Ar ions, that permit to generate half-cycle laser pulses (FWHM) with more high amplitudes and photon energy as well as spectral widths. 2.0

Lorenz-Mie resonances produced by small spheres are analyzed as a function of their size and optical properties (epsi > or < 0, mu > or < 0). New generalized (mu not equal to 1) approximate and compact expressions of the first four Lorenz-Mie coefficients (a1, b1, a2, and b2) are calculated. With these expressions and for small particles with various values of epsi and mu, the extinction cross ...

A high-resolution fluorescence microscopy technique has been developed that achieves a lateral resolution of better than one sixth of the emission wavelength (FWHM). By use of a total-internal-reflection geometry, standing evanescent waves are generated that spatially modulate the excitation of the sample. An enhanced two-dimensional image is formed from a weighted sum of images taken at differ...

Stark broadening of Zeeman absorption lines caused by inhomogeneous electric fields in highly compensated Ge has been studied by means of far-infrared magneto-optical absorption spectroscopy measurements. A number of transmutation-doped Ge single crystals with a systematically varying compensation ratio were employed. The broadening of the full width at half maximum ~FWHM! of an absorption line...

Why Bi(2)Sr(2)CaCu(2)Ox (Bi2212) allows high critical current density Jc in round wires rather than only in the anisotropic tape form demanded by all other high temperature superconductors is important for future magnet applications. Here we compare the local texture of state-of-the-art Bi2212 and Bi2223 ((Bi,Pb)(2)Sr(2)Ca(2)Cu(3)O(10)), finding that round wire Bi2212 generates a dominant a-axi...

We have observed sharp infrared spectral lines ( Deltanu approximately 60 MHz FWHM) in gamma-ray ionized para- H2 crystals. The lines are assigned to the Q1(0) transition of H2 near H+3 and H-, which becomes optically active and Stark shifted by the Coulomb fields of the ions. A simple model calculation gives a spectrum which agrees approximately with the observation. The spectrum stays the sam...

We have detected sub-wavelength spot sizes in the near-field of a metal tip, which is illuminated with terahertz (THz) pulses. The THz near-field is detected by using electro-optic detection in a (100) oriented GaP crystal. Contrary to conventional electro-optic detection, which uses (110) oriented detection crystals, (100) crystals only allow the detection of THz light, polarized perpendicular...

High-quality PbS nanocrystals were produced in multigram-scale quantities through a solventless, heterogeneous, and relatively green route. The heterogeneous nature of this reaction allows one to limit the diffusion in the system, allowing for unprecedented monodispersity and quality of the product demonstrated by a full-width at half-maximum of the photoluminescence peak (PL fwhm) as low as 52...

Results of a search for small-scale anisotropy in the cosmic microwave background (CMB) are presented. Observations were made at the South Pole using the Viper telescope, with a 0&fdg;26 (FWHM) beam and a passband centered at 40 GHz. Anisotropy band-power measurements in bands spanning the range of l in which the first acoustic peak is expected (bands centered at l=108, 173, 237, 263, 422, and ...