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.

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.

FERMI PAIRING IN DILUTE 3He-HeII MIXTURES

2006 ◽  
Vol 20 (18) ◽  
pp. 2491-2504 ◽  
Author(s):  
M. K. AL-SUGHEIR ◽  
H. B. GHASSIB ◽  
B. R. JOUDEH
Keyword(s):  
Phase Shift ◽  
Crucial Role ◽  
Relative Phase ◽  
Phase Shifts ◽  
Fermi Momentum ◽  
Relative Momentum ◽  
Many Body ◽  
S Wave ◽  
Wave Phase ◽  
Zero Values

In this paper the Galitskii–Migdal–Feynman (GMF) formalism is applied to dilute 3He-HeII mixtures. In particular, the effect of the hole-hole scattering on pairing in these systems is investigated. To this end, the relative phase shifts incorporating many-body effects based on both Brueckner–Bethe–Goldstone (BBG) and GMF formalisms are calculated. In the GMF formalism, the S-wave phase shift at zero relative momentum is –π and has a cusp at the Fermi momentum; while in the BBG formalism, this phase shift has zero values up to the Fermi momentum. From these results we conclude that hole-hole scattering plays a crucial role in any possible fermion-fermion pairing in these systems.

scholarly journals Relative phase shifts for metaplectic isotopies acting on mixed Gaussian states

2018 ◽  
Vol 59 (5) ◽  
pp. 052106 ◽  
Author(s):  
Maurice A. de Gosson ◽  
Fernando Nicacio
Keyword(s):  
Relative Phase ◽  
Phase Shifts ◽  
Gaussian States

Propagation of Cylindrically Symmetric Gaussian Beams in a Higher-Order Nonlinear Medium

1997 ◽  
Vol 06 (02) ◽  
pp. 209-234 ◽  
Author(s):  
Zlatko Jovanoski ◽  
Rowland A. Sammut
Keyword(s):  
Gaussian Beam ◽  
Analytical Solutions ◽  
Nonlinear Medium ◽  
Variational Approach ◽  
Beam Propagation ◽  
Propagation Distance ◽  
Gaussian Beams ◽  
Cylindrically Symmetric ◽  
Approximate Analytical Solutions ◽  
Symmetric Perturbation

The propagation of a cylindrically symmetric Gaussian beam in a cubic-quintic nonlinear medium is analysed via a variational approach. Explicit conditions for stationary beam propagation are determined and their stability to symmetric perturbation of the spot width is established. Approximate analytical solutions are secured for the spot width modulation with propagation distance. A comparison is made with beams propagating in a medium exhibiting a two-level saturation.

FOCUSING BEHAVIOR OF GAUSSIAN BEAM THROUGH A VARIABLE π-PHASE PLATE PLUS LENS WITH LONG FOCAL DEPTH

2008 ◽  
Vol 22 (03) ◽  
pp. 155-165
Author(s):  
JUAN LIU ◽  
XIAO-DONG SUN ◽  
BEN-YUAN GU ◽  
SHANG-QI WANG ◽  
SI DI ◽  
...  
Keyword(s):  
Gaussian Beam ◽  
Optical Tweezers ◽  
Focal Depth ◽  
Longitudinal Direction ◽  
Spot Size ◽  
Propagation Direction ◽  
Gaussian Beams ◽  
Phase Plate ◽  
Hollow Beam ◽  
Phase Functions

We investigate the optical properties of Gaussian beams diffracted by a variable π-phase plate clinging tightly to the lens with long focal depth and its dependence on the size of the π-phase plate and the preset long focal depth of the lens. The numerical results show that the π-phase plate with appropriate size plus the multifunctional lens illuminated by Gaussian beam can produce bi-focus along the propagation direction and a center hollow light, and the distance between two focal planes along the longitudinal direction and the transverse and longitudinal spot size of the hollow beam will vary when changing the size of the π-phase plate or the preset long focal depth. This investigation indicates that the distance between the focal planes and the spot sizes of the hollow light can be controlled by the appropriately chosen size of the π-phase plate and the preset long focal depth of the lens. Furthermore, we compare the optical characteristics produced by three existing phase functions of the lens with long focal depth. It is expected that this investigation will provide useful information in various optical tweezers for operating and controlling.

Scattering by a Conducting Infinite Cylinder Illuminated with a Gaussian Beam

2011 ◽  
Vol 383-390 ◽  
pp. 1938-1944
Author(s):  
Zhi Wei Shi ◽  
Bo Zhang ◽  
Xian Ming Sun
Keyword(s):  
Gaussian Beam ◽  
Cross Section ◽  
Mie Theory ◽  
Wave Functions ◽  
Infinite Cylinder ◽  
Gaussian Beams ◽  
Arbitrary Orientation ◽  
Cylinder Axis ◽  
Vector Wave ◽  
Differential Scattering Cross Section

An expansion of the incident Gaussian beam in terms of the cylindrical vector wave functions natural to an infinite cylinder of arbitrary orientation is presented. With such an expansion, the problem of interaction between a Gaussian beams and an infinite cylinder is studied in the framework of the generalized Lorenz-Mie theory. As an example, for the case of a tightly focused Gaussian beams propagating perpendicularly to the cylinder axis, the scattering characteristics are described in detail, and numerical results of the normalized differential scattering cross section are evaluated.

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