Nonspecular reflection and transmission effects: The general case of incident beams having an arbitrary profile

1983 ◽  
Vol 73 (S1) ◽  
pp. S36-S36
Author(s):  
Tran D. K. Ngoc
Keyword(s):  
Reflection And Transmission ◽  
Arbitrary Profile ◽  
Nonspecular Reflection

scholarly journals Reflection and transmission of high-frequency acoustic, electromagnetic and elastic waves at a distinguished class of irregular, curved boundaries

2019 ◽  
Vol 84 (6) ◽  
pp. 1203-1219
Author(s):  
Anthony Radjen ◽  
Gabriele Gradoni ◽  
Richard Tew
Keyword(s):  
High Frequency ◽  
Two Dimensions ◽  
Wave Number ◽  
Small Scale ◽  
Linear Wave ◽  
Incoming Wave ◽  
Reflection And Transmission ◽  
Large Wave ◽  
Irregular Boundary ◽  
Arbitrary Profile

Abstract Reflection and transmission phenomena associated with high-frequency linear wave incidence on irregular boundaries between adjacent acoustic or electromagnetic media, or upon the irregular free surface of a semi-infinite elastic solid, are studied in two dimensions. Here, an ‘irregular’ boundary is one for which small-scale undulations of an arbitrary profile are superimposed upon an underlying, smooth curve (which also has an arbitrary profile), with the length scale of the perturbation being prescribed in terms of a certain inverse power of the large wave-number of the incoming wave field. Whether or not the incident field has planar or cylindrical wave-fronts, the associated phase in both cases is linear in the wave-number, but the presence of the boundary irregularity implies the necessity of extra terms, involving fractional powers of the wave-number in the phase of the reflected and transmitted fields. It turns out that there is a unique perturbation scaling for which precisely one extra term in the phase is needed and hence for which a description in terms of a Friedlander–Keller ray expansion in the form as originally presented is appropriate, and these define a ‘distinguished’ class of perturbed boundaries and are the subject of the current paper.

Ultrasonic nonspecular reflection and transmission for an immersed multilayered composite

1999 ◽  
Author(s):  
Aziz-Ur Rehman ◽  
Catherine Potel ◽  
Ning Guo ◽  
Jean-Francois de Belleval
Keyword(s):  
Reflection And Transmission ◽  
Multilayered Composite ◽  
Nonspecular Reflection

Parabolas from Reconstructed Surfaces Observed in Convergent-Beam RHEED Patterns

1990 ◽  
Vol 48 (2) ◽  
pp. 398-399
Author(s):  
M. Gajdardziska-Josifovska
Keyword(s):  
Electron Microscopy ◽  
High Energy ◽  
Two Dimensional ◽  
High Energy Electron ◽  
Reflection And Transmission ◽  
Experimental Diffraction Pattern ◽  
Surface Resonance ◽  
Reconstructed Surfaces ◽  
Reflection Electron Microscopy ◽  
Convergent Beam

Parabolas have been observed in the reflection high-energy electron diffraction (RHEED) patterns from surfaces of single crystals since the early thirties. In the last decade there has been a revival of attempts to elucidate the origin of these surface parabolas. The renewed interest stems from the need to understand the connection between the parabolas and the surface resonance (channeling) condition, the latter being routinely used to obtain higher intensity in reflection electron microscopy (REM) images of surfaces. Several rather diverging descriptions have been proposed to explain the parabolas in the reflection and transmission Kikuchi patterns. Recently we have developed an unifying general treatment in which the parabolas are shown to be K-lines of two-dimensional lattices. Here we want to review the main features of this description and present an experimental diffraction pattern from a 30° MgO (111) surface which displays parabolas that can be attributed to the surface reconstruction.

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