Sub-wavelength surface IR imaging of soft-condensed matter

Outlined here is a technique for sub-wavelength infrared surface imaging performed using a phase matched optical parametric oscillator laser and an atomic force microscope as the detection mechanism. The technique uses a novel surface excitation illumination approach to perform simultaneously chemical mapping and AFM topography imaging with an image resolution of 200 nm. This method was demonstrated by imaging polystyrene micro-structures

Formation of Multicharged Ions at Quasi-Gasdynamic Plasma Confinement in a Mirror trap

It was shown in [1] that an increase in plasma density Ne in sources of multicharged ions leads to a substantial increase of ion current and improves slightly the ion distribution over charge states. Validity of this statement was verified in experiments with plasma densities not exceeding several units of 1012 cm-3. It was revealed [2] that, for the electron densities exceeding 1013 cm-3, the regime of plasma confinement in a trap changes significantly, the scaling described in [1] is no longer valid, and the quasi-gasdynamic regime of plasma confinement is realized. The plasma confinement time ti in this regime weakly depends on electron density. Consequently, the parameter governing formation of multicharged ions, Neti , grows as the electron density is increased. This means that an increase in plasma density results not only in an increase in the total ion current but also in the shift of the ion charge state distribution towards higher charge states. The present work concerns experimental investigation of the quasi-gasdynamic regime of confinement of a hot plasma in a direct magnetic trap and formation of multicharged ions in this regime. Experiments were conducted on the setup described in detail in [3]. Millimeter wave radiation with maximum power W=130 kW, frequency f=37.5 GHz, and pulse duration up to 1.5 ms was focused along magnetic field lines into a simple mirror trap with mirror ratio 3.4, length 25 cm, and maximum magnetic field 2.5 T. The temperature and density of the electrons were determined from spectral analysis of X-ray bremsstrahlung of plasma in the 2-20 keV range and from the transmission factor of diag-nostic microwave radiation through the plasma. It is concluded that a quasi-gasdynamic regime of plasma confinement is realized. Ion distribution over charge states in the quasi-gasdynamic regime is calculated and the re-sults obtained are compared with experimental data. A strong effect of anisotropy of the electron distribution function over energies on the efficiency of plasma confinement and formation of multicharged ions is considered. Problems of plasma stability in an axisymmetric mirror trap un-der powerful microwave pumping are addressed

The influence of spin-dependent phases of tunneling electrons on the conductance of a point ferromagnet/isolator/superconductor contact

The Andreev reflection probability for a ferromagnet/isolator/superconductor (FIS) contact at the arbitrary spin-dependent amplitudes of the electron waves transmitted through and reflected from the potential barrier is found. It is shown that Andreev reflection probabilities of electron and hole excitations in the FIS contact are different. The energy levels of Andreev bound states are found. The ballistic conductance of the point FIS contact is calculated.Comment: e.g.:10 pages, 3 figures added in tex. file: abstract and article's titl

Re-entrant superconductivity in Nb/Cu(1-x)Ni(x) bilayers

We report on the first observation of a pronounced re-entrant superconductivity phenomenon in superconductor/ferromagnetic layered systems. The results were obtained using a superconductor/ferromagnetic-alloy bilayer of Nb/Cu(1-x)Ni(x). The superconducting transition temperature T_{c} drops sharply with increasing thickness d_{CuNi} of the ferromagnetic layer, until complete suppression of superconductivity is observed at d_{CuNi}= 4 nm. Increasing the Cu(1-x)Ni(x) layer thickness further, superconductivity reappears at d_{CuNi}=13 nm. Our experiments give evidence for the pairing function oscillations associated with a realization of the quasi-one dimensional Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) like state in the ferromagnetic layer.Comment: 3 pages, 3 figures, REVTEX4/twocolum

ON THE CONVERGENCE OF MAPPINGS WITH k-FINITE DISTORTION.

We prove that a locally uniform limit of a sequence of homeomorphisms with finite k-distortion is also a mapping with finite k-distortion. We obtain also an estimation for the distortion coefficient of the limit mapping

Status of the ALICE magnet system

ALICE is the LHC experiment dedicated to heavy ion (Pb, Ca) physics. ALICE will be installed in point 2 of LHC, the former point 2 of LEP. The luminosity at the interaction point will be in the order of 10 /sup 27/ (10/sup 31/ for p-p). Consequently, the radiation level in ALICE will be comparatively low. We will use the existing infrastructure. Therefore, no noticeable civil engineering work will be necessary. Minor modifications will be made to gain a second access to the experiment cavern-mainly for the union arm spectrometer. ALICE will reuse the L3 solenoid, which is already installed and has been used in LEP as spectrometer magnet. A dipole magnet with a very large aperture is in addition required for the Dimuon Arm spectrometer and will be installed next to the L3 solenoid. The detectors in ALICE are concentrated around the IP inside L3 (Barrel) and along the muon arm. Some small forward detectors will be located toward the injection area at a larger distance from IP (~100 m). After a review of the present status of both projects some important milestones will be highlighted in the conclusion. (9 refs)