47,754 research outputs found
Light dynamics in glass-vanadium dioxide nanocomposite waveguides with thermal nonlinearity
We address the propagation of laser beams in Si02-VO2 nanocomposite
waveguides with thermo-optical nonlinearity. We show that the large
modifications of the absorption coefficient as well as notable changes of
refractive index of VO2 nanoparticles embedded into the SiO2 host media that
accompany the semiconductor-to-metal phase transition may lead to optical
limiting in the near-infrared wave range.Comment: 13 pages, 3 figures, to appear in Optics Letter
M-theory Inspired No-scale Supergravity
We propose a supergravity model that contains elements recently shown to
arise in the strongly-coupled limit of the heterotic string
(M-theory), including a no-scale--like K\"ahler potential, the identification
of the string scale with the gauge coupling unification scale, and the onset of
supersymmetry breaking at an intermediate scale determined by the size of the
eleventh dimension of M-theory. We also study the phenomenological consequences
of such scenario, which include a rather constrained sparticle spectrum within
the reach of present-generation particle accelerators.Comment: 8 pages, LaTeX, 3 figures (included
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