Fluctuations of Focal Spot within the Fresnel Zone of a Circular Focused Aperture with the Availability of Phase Errors

2006 ◽  
Vol 65 (14) ◽  
pp. 1267-1273
Author(s):  
V. V. Dolzhikov ◽  
A. V. Serbin
Keyword(s):  
Focal Spot ◽  
Fresnel Zone ◽  
Phase Errors

Investigation of axial and transverse focal spot sizes of Fresnel zone plates

2017 ◽  
Vol 56 (13) ◽  
pp. 3725 ◽  
Author(s):  
Tao Liu ◽  
Qiang Liu ◽  
Shuming Yang ◽  
Zhuangde Jiang ◽  
Tong Wang ◽  
...  
Keyword(s):  
Focal Spot ◽  
Fresnel Zone ◽  
Fresnel Zone Plates ◽  
Zone Plates

scholarly journals Controlling near-field focusing of a mesoscale binary phase plate in an optical radiation field with circular polarization

2021 ◽  
Vol 45 (4) ◽  
pp. 512-519
Author(s):  
Y.E. Geints ◽  
O.V. Minin ◽  
E.K. Panina ◽  
I.V. Minin
Keyword(s):  
Focal Spot ◽  
Fresnel Zone ◽  
Near Field ◽  
Polarized Light ◽  
Minimum Size ◽  
Phase Plate ◽  
Focal Distance ◽  
Optical Wave ◽  
Circularly Polarized Light ◽  
Binary Phase

Binary Fresnel zone plates (ZP) are one of the most frequently used focusing elements of inplane optical schemes in micro- and nanophotonics. With a decrease in the diameter and focal distance of the ZP to meso-wavelength sizes, the parameters of the focusing region begin to be significantly influenced by features of the ZP design (material, thickness, relief depth). The spatial structure of the focal spot formed in the near-field is investigated by the numerical finite elements (FEM) simulations of the transmission of a plane optical wave through a mesoscale binary phase ZP. We show that there is a range of optimal etching depths of the ZP ridges and optimal thicknesses of the plate substrate, at which the best focusing of the incident optical wave is realized in terms of the maximum field intensity and the minimum size of the focal spot. In addition, a concept of a super-focusing binary phase ZP with an immersion layer in the form of a truncated cone fabricated of ZP material is proposed, which makes it possible to focus the circularly polarized light wave into a subdiffraction region with a half-width of about "lambda"/2n (n is the ZP refractive index).

XRMF applications of a monolithic, polycapillary, focusing x-ray optic

1996 ◽  
Vol 54 ◽  
pp. 240-241
Author(s):  
D. A. Carpenter ◽  
Ning Gao ◽  
G. J. Havrilla
Keyword(s):  
Trace Elements ◽  
Point Source ◽  
Focal Spot ◽  
Fluorescence Analysis ◽  
X Rays ◽  
Focal Distance ◽  
Spot Diameter ◽  
X Ray ◽  
Focal Spot Diameter

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.

Computational Technique for the Qualification of Focal Spot Size and Shape of Industrial Radioscopy Equipment Using Star Patterns

2020 ◽  
Vol 78 (4) ◽  
pp. 479-486
Author(s):  
Marcela Tatiana Fernandes Beserra ◽  
◽  
Ricardo Tadeu Lopes ◽  
Davi Ferreira de Oliveira ◽  
Claudio Carvalho Conti ◽  
...  
Keyword(s):  
Focal Spot ◽  
Spot Size ◽  
Computational Technique ◽  
Focal Spot Size ◽  
Size And Shape
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