Results 181 to 190 of about 657 (221)

Beam wander effects on the scintillation index of a focused beam

SPIE Proceedings, 2005
First-order weak-fluctuation Rytov theory predicts that the longitudinal (on-axis) scintillation component of an untracked focused beam projected along a horizontal path will become significantly smaller as the size of the transmitter aperture increases.
Larry C. Andrews, Ronald L. Phillips, Richard J. Sasiela, Ronald Parenti   +3 more
openaire   +2 more sources

Effect of beam wander on the scintillation characterization for multiple beams

SPIE Proceedings, 2013
An 4km optical link was established to examine the effect of beam wander on the scintillation characterization for multiple focus beams. Multiple beams that sample different portions of the atmosphere reduce the scintillation if the atmospheric turbulence each beam traverses is independent.
Wu-ming Wu, Quan Sun, Guang-sen Ren, Yu Ning, Rui Du, Yi Wu   +5 more
openaire   +1 more source

Beam wander characteristics of cos and cosh-Gaussian beams

Applied Physics B, 2009
Within the context of a general beam formulation, beam wander characteristics of cos and cosh-Gaussian beams are derived and numerically evaluated. In our graphs, the fundamental Gaussian beam is used as a benchmark for comparisons. The associated plots reveal that at small source sizes, a cos-Gaussian beam has the lowest beam wander, while this ...
C. Z. Çil, H. T. Eyyuboğlu, Y. Baykal, Y. Cai   +3 more
openaire   +1 more source

Beam wander of a collimated beam: comparing theory and experiment

SPIE Proceedings, 2008
In this paper we present experimental beam wander measurements and compare them with theory developed from the Kolmogorov model for the atmosphere. Data from a collimated beam over a 1km horizontal terrestrial path were recorded with a high-speed camera.
Wayne, David T., Phillips, Ronald L., Andrews, Larry C., Griffis, Brad   +3 more
openaire   +2 more sources

Comparing Models and Approximations of Beam Wander

2024 14th International Symposium on Communication Systems, Networks and Digital Signal Processing (CSNDSP)
Free space optical communication is a new and promising area with many desirable properties. However, there is no standardized way to model losses and effects of the atmosphere on the propagating beam. This necessitates comparing different models and approximations that are widely used in the literature. We calculate and compare various aspects of beam
Galambos, Máté, Cossu, Giulio, Ciaramella, Ernesto   +2 more
openaire   +3 more sources

Spectrum of the beam wandering noise

2010 9th International Conference on Environment and Electrical Engineering, 2010
Phenomenon of the atmospheric turbulence is well-known from the optical communication systems. In communication systems, only influence of the turbulent flow on the transmitter plane wave affects the beam. In the rangefinder system, influence on the reflected spherical wave and reflecting surface changes caused by the beam wandering phenomenon are ...
openaire   +1 more source

Beam wander experiments: terrestrial path

SPIE Proceedings, 2006
We report on a set of measurements made in December 2005 by researchers from the University of Central Florida, SPAWAR's Innovative Science and Technology Experiment Facility (ISTEF), Harris Corporation, NASA Kennedy Space Center, and Northrop Grumman.
R. L. Phillips, L. C. Andrews, J. Stryjewski, B. Griffis, M. Borbath, D. Galus, G. Burdge, K. Green, C. Kim, D. Stack, C. Harkrider, D. Wayne, D. Hand, J. Kiriazes   +13 more
openaire   +2 more sources

Beam wandering of thin parallel beams through atmospheric turbulence

Waves in Random Media, 1991
Abstract Wandering and correlation of wandering of two parallel laser beams after crossing atmospheric turbulence are theoretically and experimentally investigated. A general expression is given, valid for propagation through a thick layer of turbulence, which includes as a particular case that of a path completely filled with turbulence. Two different
CONSORTINI, ANNA, Kevin A. O'Donnell
openaire   +3 more sources

Beam wander of dark hollow, flat-topped and annular beams

Applied Physics B, 2008
Benefiting from the earlier derivations for the Gaussian beam, we formulate beam wander for dark hollow (DH) and flat-topped (FT) beams, also covering the annular Gaussian (AG) beam as a special case. Via graphical illustrations, beam wander variations of these beams are analyzed and compared among themselves and to the fundamental Gaussian beam ...
H. T. Eyyuboğlu, C. Z. Çil
openaire   +1 more source

Modeling the PDF for the irradiance of an uplink beam in the presence of beam wander

SPIE Proceedings, 2006
ABSTRACT Recent studies of ground-to-space beam propagation have revealed significant departures from Rytov theory when the beam diameter w 0 is on the order of the atmospheric coherence width r 0 . It has been shown that such departures from Rytov theory are primarily a consequence of beam wander and other low-order aberrations.
Parenti, Ronald, Sasiela, Richard J., Andrews, Larry C., Phillips, Ronald L.   +3 more
openaire   +2 more sources