15,178 research outputs found
Dielectric-waveguide mode of light propagation in p-n junctions
The condition for coherent laser emission from forward-biased p-n junctions [1-3] can be written as [4] [equation 1]...
In order for the reported values [1-3] of Ic/A to agree with Eq. (1), must must use values pf d ~50 μ [4]. The question arises as to the nature of the mechanism which could confine the light generated near the junction to such small distances
Perturbations to observed ambient neutral densities due to presence of an Orbiting Geophysical Observatory
Perturbations in density of ions and neutral particles in upper atmosphere due to OG
Ab initio calculation of the dynamical properties of PPP and PPV
In this work, we have calculated the vibrational modes and frequencies of the
crystalline PPP (in both the Pbam and Pnnm symmetries) and PPV (in the P21/c
symmetry). Our results are in good agreement with the available experimental
data. Also, we have calculated the temperature dependence of their specific
heats at constant volume, and of their vibrational entropies. Based on our
results, at high temperatures, the PPP is more stable in the Pnnm structure
than in the Pbam one.Comment: 5 pages, 7 figures, accepted for publication in Braz. J. Phys.,
special number, Proceedings of BWSP-12, 12th Brazilian Workshop on
Semiconductor Physic
Phonon-assisted and phonon-free radiative transitions in sulfur-doped GaAs diffused junctions
In the course of electroluminescence studies of GaAs junctions we investigated the emission spectra of sulfur-doped zinc-diffused diodes. The peaks in the spectra correspond to three main transitions and their associated phonon emission satellites
Reduction and analysis of data from OGO-4 experiment 15 Final report, 1 Nov. 1969 - 30 Nov. 1970
Procedures for processing atmospheric composition data obtained through use of sweeping quadrupole mass spectrometer on OGO-4 satellit
Detection of Spiral photons in Quantum Optics
We show that a new type of photon detector, sensitive to the gradients of
electromagnetic fields, should be a useful tool to characterize the quantum
properties of spatially-dependent optical fields. As a simple detector of such
a kind, we propose using magnetic dipole or electric quadrupole transitions in
atoms or molecules and apply it to the detection of spiral photons in
Laguerre-Gauss (LG) beams. We show that LG beams are not true hollow beams, due
to the presence of magnetic fields and gradients of electric fields on beam
axis. This approach paves the way to an analysis at the quantum level of the
spatial structure and angular momentum properties of singular light beams.Comment: 5 pages, 4 figure
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