DIFFRACTION OF 3.2 CM. ELECTROMAGNETIC WAVES BY CYLINDRICAL OBJECTS

1954 ◽  
Vol 32 (6) ◽  
pp. 372-380 ◽  
Author(s):  
A. B. McLay ◽  
S. T. Wiles
Keyword(s):  
Electromagnetic Waves ◽  
Incident Beam ◽  
Diffraction Theory ◽  
Central Peak ◽  
Beam Direction ◽  
Cylinder Axis ◽  
Scalar Diffraction ◽  
Conducting Cylinder ◽  
Scalar Diffraction Theory ◽  
Diffraction Patterns

Diffraction patterns of a brass tube and a hard rubber rod, each a cylinder of 1 in. diameter, in a nearly plane beam of square-wave modulated 3 cm. waves with electric vector parallel to the cylinder axis, have been measured in several planes transverse to the incident beam direction. Experimental results for the conducting cylinder agree closely with calculations based on scalar diffraction theory. Patterns of the dielectric rod show a pronounced central peak immediately behind the rod and other intensity effects differing from the conducting cylinder patterns, particularly in the vicinity of the shadow.

DIFFRACTION OF 3.2 CM. ELECTROMAGNETIC WAVES BY DIELECTRIC RODS: I. LUCITE AND TENITE 1 IN. DIAMETER CYLINDERS

1956 ◽  
Vol 34 (6) ◽  
pp. 546-554 ◽  
Author(s):  
M. K. Subbarao ◽  
A. B. McLay
Keyword(s):  
Electromagnetic Waves ◽  
Incident Beam ◽  
Geometrical Optics ◽  
Dielectric Constants ◽  
Electric Vector ◽  
Beam Direction ◽  
Cylinder Axis ◽  
Experimental Conditions ◽  
Surface Reflection ◽  
Diffraction Patterns

Diffraction patterns of lucite and tenite cylindrical rods of approximately one inch diameter, in a nearly plane beam of square-wave modulated 3.2 cm. waves with electric vector parallel to the cylinder axis, have been measured in several planes transverse to the incident beam direction. Patterns are compared with theoretical ones (Froese and Wait 1954) and with ones obtained earlier, under similar experimental conditions, for brass and hard rubber cylinders (Wiles and McLay 1954). Some general marked trends in the patterns of the four rods, comprising a conductor, two nearly lossless dielectrics with different dielectric constants, and a lossier dielectric, are related to the effects of transmission and/or surface reflection expected from geometrical optics considerations.

DIFFRACTION OF 3.2 CM. ELECTROMAGNETIC WAVES BY DIELECTRIC RODS: II. LUCITE IN. DIAMETER CYLINDER AND SEMICYLINDER

1956 ◽  
Vol 34 (6) ◽  
pp. 555-562 ◽  
Author(s):  
A. B. McLay ◽  
M. K. Subbarao
Keyword(s):  
Electromagnetic Waves ◽  
Incident Beam ◽  
Geometrical Optics ◽  
Electric Vector ◽  
Beam Direction ◽  
Cylinder Axis ◽  
Square Wave ◽  
Surface Reflection ◽  
Plane Face ◽  
Diffraction Patterns

Diffraction patterns of a lucite cylinder and a half cylinder in a nearly plane beam of square-wave modulated 3.2 cm. waves, with electric vector parallel to the cylinder axis, have been measured in several planes transverse to the incident beam direction. Patterns of the half cylinder were obtained with the plane face toward and away from the source of radiation. Marked trends in the patterns are related qualitatively to the effects of transmission and surface reflection, both external and internal, expected from geometrical optics considerations.

Electron Diffraction Study of Multilayer Structures with Partially Coherent Illumination

1985 ◽  
Vol 62 ◽  
Author(s):  
N. Otsuka ◽  
C. Choi ◽  
L. A. Kolodziejski ◽  
R. L. Gunshor
Keyword(s):  
Electron Diffraction ◽  
Incident Beam ◽  
Electron Diffraction Study ◽  
Diffraction Theory ◽  
Diffraction Spot ◽  
Multilayer Structures ◽  
Intensity Calculations ◽  
Diffraction Patterns ◽  
Monochromatic Source

ABSTRACTThe effect of partial coherency on electron diffraction patterns of Cd1−xMnxTe – Cd1−yMny Te superlattices has been investigated. Observed diffraction patterns are compared with intensity calculations performed using dynamical diffraction theory with a model of an extended incoherent monochromatic source. From this study, a new method of electron diffraction for characterization of multilayer structures can be developed. Under the condition that the lateral coherent distance of the incident beam covers two adjacent layers, diffraction beams arising from the two layers give rise to an interference fringe in a diffraction spot. With this type of diffraction pattern, one can determine the refractive index of a crystal in the multilayer structure.

Relationship between the technique of integral equation and Kirchhoff approximation in scalar diffraction theory

2020 ◽  
Author(s):  
Grygorij S. Tymchik ◽  
Maryna V. Filippova ◽  
Oleg S. Bezverkhyi ◽  
Waldemar Wójcik ◽  
Bakhyt Yeraliyeva ◽  
...  
Keyword(s):  
Integral Equation ◽  
Diffraction Theory ◽  
Kirchhoff Approximation ◽  
Scalar Diffraction ◽  
Scalar Diffraction Theory

scholarly journals Multidither coherent optical adaptive technique for deep tissue two-photon microscopy

2019 ◽  
Vol 12 (04) ◽  
pp. 1942003 ◽  
Author(s):  
Biwei Zhang ◽  
Wei Gong ◽  
Chenxue Wu ◽  
Lejia Hu ◽  
Xinpei Zhu ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Diffraction Theory ◽  
Fluorescence Signal ◽  
Two Photon Microscopy ◽  
Scalar Diffraction ◽  
Two Photon ◽  
Scalar Diffraction Theory ◽  
Adaptive Technique ◽  
Photon Imaging ◽  
Two Photon Imaging

Two-photon microscopy normally suffers from the scattering of the tissue in biological imaging. Multidither coherent optical adaptive technique (COAT) can correct the scattered wavefront in parallel. However, the determination of the corrective phases may not be completely accurate using conventional method, which undermines the performance of this technique. In this paper, we theoretically demonstrate a method that can obtain more accurate corrective phases by determining the phase values from the square root of the fluorescence signal. A numerical simulation model is established to study the performance of adaptive optics in two-photon microscopy by combining scalar diffraction theory with vector diffraction theory. The results show that the distortion of the wavefront can be corrected more thoroughly with our method in two-photon imaging. In our simulation, with the scattering from a 450-[Formula: see text]m-thick mouse brain tissue, excitation focal spots with higher peak-to-background ratio (PBR) and images with higher contrast can be obtained. Hence, further enhancement of the multidither COAT correction performance in two-photon imaging can be expected.

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