A method for predicting the reflection and refraction of spherical waves across a planar interface

1994 ◽  
Vol 76 (1) ◽  
pp. 25-32 ◽  
Author(s):  
J. R. Furlong ◽  
Catherine F. Westbury ◽  
E. A. Phillips
Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Maxim Mazanov ◽  
Danica Sugic ◽  
Miguel A. Alonso ◽  
Franco Nori ◽  
Konstantin Y. Bliokh

Abstract Transverse (Hall-effect) and Goos–Hänchen shifts of light beams reflected/refracted at planar interfaces are important wave phenomena, which can be significantly modified and enhanced by the presence of intrinsic orbital angular momentum (OAM) in the beam. Recently, optical spatiotemporal vortex pulses (STVPs) carrying a purely transverse intrinsic OAM were predicted theoretically and generated experimentally. Here we consider the reflection and refraction of such pulses at a planar isotropic interface. We find theoretically and confirm numerically novel types of OAM-dependent transverse and longitudinal pulse shifts. Remarkably, the longitudinal shifts can be regarded as time delays, which appear, in contrast to the well-known Wigner time delay, without temporal dispersion of the reflection/refraction coefficients. Such time delays allow one to realize OAM-controlled slow (subluminal) and fast (superluminal) pulse propagation without medium dispersion. These results can have important implications in various problems involving scattering of localized vortex states carrying transverse OAM.


2000 ◽  
Vol 6 (S2) ◽  
pp. 156-157
Author(s):  
K.T. Moore ◽  
E.A. Stach ◽  
J.M. Howe ◽  
D.C. Elbert ◽  
D.R. Veblen

When acquiring energy-filtered TEM (EFTEM) images of a crystalline material, the detrimental effects of diffraction contrast can often be seen in raw energy-filtered images (EFI) (i.e., pre-edge and post-edge images), jump-ratio images and elemental maps as residual diffraction contrast. Residual diffraction contrast occurs in raw EFI because of plural scattering (i.e., inelastic-elastic and elastic-inelastic electron scattering) and in jump-ratio images and elemental maps because background removal procedures often are unable to completely account for intensity changes due to dynamical effects (elastic scattering) that occur between pre-edge and post-edge images acquired at different energy losses.It is demonstrated in these experiments that, when examining a planar interface, EFTEM images have increased compositional contrast and decreased residual diffraction contrast when the sample is oriented so that the interface is parallel to the electron beam, but not directly on a zone axis.


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