75,071 research outputs found
Fiber distributed feedback laser
Utilizing round optical fibers as communication channels in optical communication networks presents the problem of obtaining a high efficiency coupling between the optical fiber and the laser. A laser is made an integral part of the optical fiber channel by either diffusing active material into the optical fiber or surrounding the optical fiber with the active material. Oscillation within the active medium to produce lasing action is established by grating the optical fiber so that distributed feedback occurs
Proposed Distributed Feedback Crystal Cavities for X-Ray Lasers
The strong interest in the coherent generation and guiding
of x rays is well known. Many papers have recently
appeared treating different concepts of stimulated x-ray
emissions, and x-ray guiding in thin films was achieved.
Crystals were suggested as end reflectors to generate feedback.
Here we suggest a different type of cavity using zeolite
crystals that would guide the emitted x-rays and at
the same time generate the necessary feedback for self-sustained
oscillation
Laser action generated within a light pipe: A concept
Laser light could be generated within light pipe itself, thereby eliminating coupling losses. Theoretical calculations have shown feasibility of light-pipe laser propagating in circularly-polarized TE mode. It is predicted that fiber-optic distributed-feedback laser would have gain on order of 25 dB
Hard rod gas with long-range interactions: Exact predictions for hydrodynamic properties of continuum systems from discrete models
One-dimensional hard rod gases are explicitly constructed as the limits of
discrete systems: exclusion processes involving particles of arbitrary length.
Those continuum many-body systems in general do not exhibit the same
hydrodynamic properties as the underlying discrete models. Considering as
examples a hard rod gas with additional long-range interaction and the
generalized asymmetric exclusion process for extended particles (-ASEP),
it is shown how a correspondence between continuous and discrete systems must
be established instead. This opens up a new possibility to exactly predict the
hydrodynamic behaviour of this continuum system under Eulerian scaling by
solving its discrete counterpart with analytical or numerical tools. As an
illustration, simulations of the totally asymmetric exclusion process
(-TASEP) are compared to analytical solutions of the model and applied to
the corresponding hard rod gas. The case of short-range interaction is treated
separately.Comment: 19 pages, 8 figure
Status of Lattice QCD
Significant progress has recently been achieved in the lattice gauge theory
calculations required for extracting the fundamental parameters of the standard
model from experiment. Recent lattice determinations of such quantities as the
kaon parameter, the mass of the quark, and the strong coupling constant
have produced results and uncertainties as good or better than the best
conventional determinations. Many other calculations crucial to extracting the
fundamental parameters of the standard model from experimental data are
undergoing very active development. I review the status of such applications of
lattice QCD to standard model phenomenology, and discuss the prospects for the
near future.Comment: 20 pages, 8 embedded figures, uuencoded, 2 missing figures. (Talk
presented at the Lepton-Photon Symposium, Cornell University, Aug. 10-15,
1993.
Highly loaded multi-stage fan drive turbine: Leaned stator configuration design
The results of the high lift blade configuration design study are reported. The three-stage constant-inside-diameter turbine utilizes a ten degree tangentially leaned stator in stage three. All other bladerows use plain blades. Analysis of the leaned stator is discussed, and detailed design data are summarized. Steady-state stresses are discussed, and the results of the mechanical design analysis are presented
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