Effects of a modified spectrum on the wave structure function of a Gaussian beam

1994 ◽  
Author(s):  
Larry C. Andrews ◽  
Cynthia Y. Young
Keyword(s):  
Structure Function ◽  
Gaussian Beam ◽  
Wave Structure

scholarly journals Wave Structure Function and Long-Exposure MTF for Gaussian-Beam Waves Propagating in Anisotropic Maritime Atmospheric Turbulence

2020 ◽  
Vol 10 (16) ◽  
pp. 5484
Author(s):  
Bing Guan ◽  
Haiyang Yu ◽  
Wei Song ◽  
Jaeho Choi
Keyword(s):  
Structure Function ◽  
Gaussian Beam ◽  
Atmospheric Turbulence ◽  
Isotropic Turbulence ◽  
Imaging System ◽  
Wave Structure ◽  
Modulation Transfer ◽  
Horizontal Path ◽  
Kolmogorov Turbulence ◽  
Waves Propagation

The expressions of wave structure function (WSF) and long-exposure modulation transfer function (MTF) for laser beam propagation through non-Kolmogorov turbulence were derived in our previous work. In this paper, based on anisotropic maritime atmospheric non-Kolmogorov spectrum, the new analytic expression of WSF for Gaussian-beam waves propagation through turbulent atmosphere in a horizontal path is derived. Moreover, using this newly derived expression, long-exposure MTF for Gaussian-beam waves is obtained for analyzing the degrading effects in an imaging system. Using the new expressions, WSF and MTF for Gaussian-beam waves propagating in terrestrial and maritime atmospheric turbulence are evaluated. The simulation results show that Gaussian-beam waves propagation through maritime turbulence obtain more degrading effects than terrestrial turbulence due to the humidity and temperature fluctuations. Additionally, the degrading effects under anisotropic turbulence get less loss than that of isotropic turbulence.

Interferential seeing monitor, a seeing monitor for atmospheric turbulence studies: calibration with the differential image motion monitor

2020 ◽  
Vol 500 (2) ◽  
pp. 1884-1888
Author(s):  
Mohammed Sabil ◽  
A Habib ◽  
Z Benkhaldoun
Keyword(s):  
Structure Function ◽  
Atmospheric Turbulence ◽  
Wave Structure ◽  
Image Motion ◽  
Phase Fluctuations ◽  
Amplitude Fluctuations ◽  
Focus Plane ◽  
Cross Calibration ◽  
Double Slit ◽  
Good Agreement

ABSTRACT In this work, we aim to calibrate an interferential seeing monitor (ISM), which is a testing instument used at astronomical sites. Its method is based on the study of the diffraction pattern produced by a Young’s double-slit at the focus plane of a telescope. This method allows us to obtain the wave structure function by taking into account both phase and amplitude fluctuations of the light wavefront. A phase seeing εϕ was assigned to phase fluctuations and an amplitude seeing εχ was assigned to amplitude fluctuations (scintillation phenomenon), which allows us to obtain both phase and amplitude fluctuations. The feasibility of the ISM method was demonstrated by numerical simulations presented in a previous work. In this work, we have conducted a cross-calibration campaign of the ISM with a differential image motion monitor (DIMM) over 16 nights at the Oukaimeden and Atlas Golf Marrakech Observatories. The goal of this campaign was to study the reliability of this new method. In this paper, we present the calibration measurements and a comparison between the seeing measured by the ISM (εϕ, εχ) and that obtained by the DIMM (εdimm). These results show good agreement between the phase- eeing εϕ and εdimm.

scholarly journals Effects of Turbulence on the Vortex Modes Carried by Quasi-Diffracting Free Finite Energy Beam in Ocean

2020 ◽  
Vol 8 (6) ◽  
pp. 458
Author(s):  
Qiyong Liang ◽  
Yixin Zhang ◽  
Dongyu Yang
Keyword(s):  
Gaussian Beam ◽  
Cone Angle ◽  
Wave Structure ◽  
Beam Width ◽  
Finite Energy ◽  
Energy Beam ◽  
Initial Beam ◽  
Oceanic Turbulence ◽  
Wireless Optical Communication ◽  
Ellipticity Parameter

By developing new wave structure function of a beam waves, we derive the transmitting probability of signal vortex modes in oceanic turbulence based on Rytov approximation theory. Applying this transmitting probability of signal vortex modes, we study the influence of oceanic turbulence on the transmittance of the vortex modes carried by Mathieu-Gaussian beam. This model shows the transmitting probability of Mathieu-Gaussian beam with narrow initial beam width, long wavelength, and small ellipticity parameter is higher than the transmitting probability of the signal vortex modes in case of the beam with wide initial beam width, short wavelength, and great ellipticity parameter. Furthermore, when Mathieu-Gaussian beam has a suitable semi-cone angle, the effect of weak-turbulence channel on the transmitting probability of signal vortex modes with different topological charge can be ignored. Mathieu-Gaussian beam is a more suitable carrier for high information channel of underwater wireless optical communication than Laguerre-Gaussian beam.

Study on the wave structure function and spatial coherence radius with a power-law spectrum of oceanic turbulence

Optik ◽  
2019 ◽  
Vol 187 ◽  
pp. 172-184
Author(s):  
Peng Yue ◽  
Dongling Xu ◽  
Xiang Yi ◽  
Zongmin Cui ◽  
Xiaohui Luan ◽  
...  
Keyword(s):  
Structure Function ◽  
Power Law ◽  
Spatial Coherence ◽  
Wave Structure ◽  
Oceanic Turbulence

Theoretical wave structure function when the effect of the outer scale is significant

2007 ◽  
Vol 46 (4) ◽  
pp. 559 ◽  
Author(s):  
Robert L. Lucke ◽  
Cynthia Y. Young
Keyword(s):  
Structure Function ◽  
Wave Structure ◽  
Outer Scale
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