263 research outputs found
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Diode-pumped solid state lasers (DPSSLs) for Inertial Fusion Energy (IFE)
The status of diode-pumped, transverse-gas-flow cooled, Yb-S-FAP slab lasers is reviewed. Recently acquired experimental performance data are combined with a cost/performance IFE driver design code to define a cost-effective development path for IFE DPSSL drivers. Specific design parameters are described for the Mercury 100J/10 Hz, 1 kW system (first in the development scenario)
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New solid state lasers from the ultraviolet to the mid-infrared
The authors discuss three new laser materials that offer improved access to the ultraviolet, near infrared and mid-infrared spectral regions. In order for each of these materials to have been identified, a particular hurdle needed to be overcome with respect to the fundamental laser physics impacting the material. In the case of the 280-320nm Ce:LiSAF laser, the main issue is the need to reduce the loss associated with excited state absorption, while for 1047nm Yb:S-FAP it is the ground state absorption at the laser wavelength that must be minimized. Cr:ZnSe has been down-selected from a number of potential candidates which could lase in the 2200-3000nm region, in order to mitigate the detrimental impact of nonradiative decay. In all three cases the authors discuss how appropriate consideration of fundamental concerns has led to the identification and understanding of the new laser system
Evidence for Surface Andreev Bound states in Cuprate Superconductors from Penetration Depth Measurements
Tunneling and theoretical studies have suggested that Andreev bound states
form at certain surfaces of unconventional superconductors. Through studies of
the temperature and field dependence of the in-plane magnetic penetration depth
lambda_ab at low temperature, we have found strong evidence for the presence of
these states in clean single crystal YBCO and BSCCO. Crystals cut to expose a
[110] interface show a strong upturn in lambda_ab at around 7K, when the field
is oriented so that the supercurrents flow around this surface. In YBCO this
upturn is completely suppressed by a field of ~0.1 T.Comment: 4 pages 2 column revtex + 4 postscript figures. Submitted to PR
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New tunable lasers for potential use in LIDAR systems
We discuss the optical and laser properties of two new tunable laser crystals, Ce:LiSrAlF{sub 6} and Cr:ZnSe. These crystals are unique in that they provide a practical alternative to optical parametric oscillators as a means of generating tunable radiation in the near ultraviolet and mid-infrared regions (their tuning ranges are at least 285-315 nm and 2.2-2.8 microns, respectively). While these crystals are relatively untested in field deployment, they are promising and likely to be useful in the near future
Theory of magnetotunneling spectroscopy in spin triplet p-wave superconductors
We study the influence of a magnetic field on the zero-bias conductance
peak (ZBCP) due to zero-energy Andreev bound state (ZES) in normal metal /
unconventional superconductor. For p-wave junctions, ZBCP does not split into
two by even for sufficiently low transparent junctions, where ZBCP clearly
splits for d-wave. This unique property originates from the fact that for
p-wave superconductors, perpendicularly injected quasiparticle form ZES, which
contribute most dominantly on the tunneling conductance. In addition, we show
that for +i-wave superconductor junctions, the height of ZBCP is
sensitive to due to the formation of broken time reversal symmetry state.
We propose that tunneling spectroscopy in the presence of magnetic field,
, , is an promising method to determine the pairing
symmetry of unconventional superconductors.Comment: 4 pages, 6 figures, using jpsj2.cl
Evidence of a d to s-wave pairing symmetry transition in the electron-doped cuprate superconductor PrCeCuO
We present point contact spectroscopy (PCS) data for junctions between a
normal metal and the electron doped cuprate superconductor
PrCeCuO (PCCO). For the underdoped compositions of this cuprate
() we observe a peak in the conductance-voltage characteristics of
the point contact junctions. The shape and magnitude of this peak suggests the
presence of Andreev bound states at the surface of underdoped PCCO which is
evidence for a d-wave pairing symmetry. For overdoped PCCO () the
PCS data does not show any evidence of Andreev bound states at the surface
suggesting an s-wave pairing symmetry.Comment: 4 pages Latex, 4 eps figures included. Submitted to Phys. Rev. Let
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