A fast Gaussian beam tracing method for reflection and refraction of general vectorial astigmatic Gaussian beams from general curved surfaces

2004 ◽  
Vol 232 (1-6) ◽  
pp. 1-10 ◽  
Author(s):  
A. Rohani ◽  
A.A. Shishegar ◽  
S. Safavi-Naeini
Keyword(s):  
Gaussian Beam ◽  
Gaussian Beams ◽  
Curved Surfaces ◽  
Reflection And Refraction ◽  
Tracing Method

Relative phase shifts of apertured Gaussian beams and transformation of a Gaussian beam through a phase aperture

1997 ◽  
Vol 36 (4) ◽  
pp. 772 ◽  
Author(s):  
Zhiping Jiang ◽  
Qisheng Lu ◽  
Zejin Liu
Keyword(s):  
Gaussian Beam ◽  
Relative Phase ◽  
Phase Shifts ◽  
Gaussian Beams

Gaussian beam migration

Geophysics ◽  
1990 ◽  
Vol 55 (11) ◽  
pp. 1416-1428 ◽  
Author(s):  
N. Ross Hill
Keyword(s):  
Gaussian Beam ◽  
Wave Field ◽  
Seismic Source ◽  
Velocity Model ◽  
Downward Continuation ◽  
Gaussian Beams ◽  
Seismic Velocities ◽  
Migration Method ◽  
Gaussian Beam Migration ◽  
Lateral Variations

Just as synthetic seismic data can be created by expressing the wave field radiating from a seismic source as a set of Gaussian beams, recorded data can be downward continued by expressing the recorded wave field as a set of Gaussian beams emerging at the earth’s surface. In both cases, the Gaussian beam description of the seismic‐wave propagation can be advantageous when there are lateral variations in the seismic velocities. Gaussian‐beam downward continuation enables wave‐equation calculation of seismic propagation, while it retains the interpretive raypath description of this propagation. This paper describes a zero‐offset depth migration method that employs Gaussian beam downward continuation of the recorded wave field. The Gaussian‐beam migration method has advantages for imaging complex structures. Like finite‐difference migration, it is especially compatible with lateral variations in velocity, but Gaussian beam migration can image steeply dipping reflectors and will not produce unwanted reflections from structure in the velocity model. Unlike other raypath methods, Gaussian beam migration has guaranteed regular behavior at caustics and shadows. In addition, the method determines the beam spacing that ensures efficient, accurate calculations. The images produced by Gaussian beam migration are usually stable with respect to changes in beam parameters.

An efficient ray-tracing method and its application to Gaussian beam migration in complex multilayered anisotropic media

Geophysics ◽  
2018 ◽  
Vol 83 (5) ◽  
pp. T281-T289 ◽  
Author(s):  
Qianru Xu ◽  
Weijian Mao
Keyword(s):  
Gaussian Beam ◽  
Ray Tracing ◽  
Initial Conditions ◽  
Anisotropic Media ◽  
Memory Storage ◽  
Ray Tracing Method ◽  
Embedded Discontinuities ◽  
Model Parameterization ◽  
Gaussian Beam Migration ◽  
Tracing Method

We have developed a fast ray-tracing method for multiple layered inhomogeneous anisotropic media, based on the generalized Snell’s law. Realistic geologic structures continuously varying with embedded discontinuities are parameterized by adopting cubic B-splines with nonuniformly spaced nodes. Because the anisotropic characteristic is often closely related to the interface configuration, this model parameterization scheme containing the natural inclination of the corresponding layer is particularly suitable for tilted transverse isotropic models whose symmetry axis is generally perpendicular to the direction of the layers. With this model parameterization, the first- and second-order spatial derivatives of the velocity within the interfaces can be effectively obtained, which facilitates the amplitude computation in dynamic ray tracing. By using complex initial conditions for the dynamic ray system and taking the multipath effect into consideration, our method is applicable to Gaussian beam migration. Numerical experiments of our method have been used to verify its effectiveness, practicability, and efficiency in memory storage and computation.

Turbulent Distance of Partially Coherent Hollow Gaussian Beams

2011 ◽  
Vol 321 ◽  
pp. 256-260
Author(s):  
Bang Yuan Hao
Keyword(s):  
Gaussian Beam ◽  
Optical Communication ◽  
Beam Propagation ◽  
Gaussian Beams ◽  
Partially Coherent ◽  
Propagation Factor ◽  
Communication Links ◽  
Beam Propagation Factor ◽  
Angular Spreading

For partially coherent hollow Gaussian beam (HGB), the turbulent distance, in which all of the spatial and angular spreading and the beam propagation factor increasing due to turbulence can be neglected, has been investigated in detail. It is shown that the turbulent distance of partial coherent HGBs increases with increasing beam order and wavelength, and decreasing turbulent parameter and coherent parameter. With increasing waist width, the turbulent distance first increases and then decreases. Furthermore, the turbulent distance of a HGB is much larger than that of the corresponding Gaussian Schell-model (GSM) beam when choosing the appropriate value of the waist width, implying that a HGB may be more appropriate to be used in optical communication links than a GSM beam.

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