Fresnel zones

Fresnel zone plate producing a virtual image (any cross section of the hyperboloids) [29]... 

To produce micrometer sized focused beams, one employs highly demagnifying optics to image the source onto the sample. Such optics can include Kirkpatrick-Baez mirrors, Fresnel zone plates, tapered capillaries, and compound refractive lenses, all of which have been used to produce submicron focal spots at third generation storage rings. 

Diffraction-based focusing devices include Fresnel zone plate (FZP) multilayer structures. Zone plates operating in the hard X-ray regime have achieved sub-micrometer beams (Yun et al. 1999 Kagoshima et al. 2001 Suzuki et al. 2001) at the expense of... 

Sutton SR, Rivers ML (1999) Hard X-ray synchrotron microprobe techniques and applications. In Synchrotron Methods in Clay Science. CMS Workshop Lectures Vol. 9. Schulze DG, Stucki JW, Bertsch PM. (eds). The Clay Mineral Society, Boulder CO, p 146-163 Sutton SR, Flynn G, Rivers M, Newville M, Eng P (2000) X-ray fluorescence microtomography of individual interplanetary dust particles. Lunar Planet Sci XXXI 1857 Sutton SR, Rivers ML, Bajt S, Jones KW, Smith JV (1994) Synchrotron X-ray-fluorescence microprobe-a microanalytical instrument for trace element studies in geochemistry, cosmochemistry, and the soil and environmental sciences. Nucl Instrum Methods Phys Res A 347 412-416 Suzuki Y, Awaji M, Kohmura Y, Takeuchi A, Takano H, Kamijo N, Tamura S, Yasumoto M, Handa (2001) X-ray microbeam with sputtered-shced Fresnel zone plate at SPring-8 undulator beamline. Nucl Instrum Methods Phys Res A 467-468 951-953... 

Abstract. Many different patterns have been proposed for coded masks, from Fresnel zone plates, through scatter-hole designs, to various patterns which are optimal in different senses. We present a compendium of such patterns, with examples and their autocorrelation functions, together with a bibliography of associated literature. 

Since Mertz and Young (1961) introduced the concept of indirect imaging using shadows cast by Fresnel Zone plates, a wide range of patterns has been proposed for what has become known as coded mask imaging . Visually some of these patterns are strikingly different, while in many cases their performance, encapsulated in the autocorrelation function (ACE) of the mask pattern, is identical to that of other patterns. We present a compilation of patterns which have been proposed. 

The field of view of the system is defined by the fringe pattern. It extends to an angle of tan The fringe pattern contains satellite Fresnel zones... 

Another important new direction is improving the spatial resolution of APXPS, in particular, for the investigation of inhomogeneous samples, such as industrial catalysts and electrochemical devices. This can be achieved by focusing the incident X-rays using either Kirkpatrick-Baez mirror pairs (for hard X-rays, beam spots of 100 run have been achieved [79]) or Fresnel zone plates, for which a spatial resolution of 10 nm was demonstrated in the soft X-ray regime [80]. 

Microbeam X-ray diffraction with beam sizes in the micrometer range is a useful and powerful method to investigate the in situ transition of the crystalline region and the local structure for monofilaments. To reveal the detailed fiber structure and the distribution of the two types of molecular conformations (a- and P-structure crystals) in monofilaments, microbeam X-ray diffraction was performed using synchrotron radiation at SPring-8, Japan. The beam size was focused to 0.5 pm with a Fresnel zone plate (Suzuki et al. 2001) and the monofilament was linearly scanned perpendicularly to the fiber axis with a step of 2 pm. 

In a free space, the sound source can be considered as a point source (see Figure 13.1). In practical industrial applications, however, sound is either radiated from the source of definite size (e.g., loudspeaker membrane) or, more frequently, reflected from the point source by surfaces of different shapes such as horn, paraboloid, ellipsoid, etc. In both cases such sound radiation can be regarded as coming from a plane source. This results in a specific pattern of sound intensity in the zone near the sound source, the sound intensity is constant (Fresnel zone), whereas outside this zone (the Fraunhofer zone) the sound intensity decreases inversely with the square of the distance from the plane source, i.e., in the same way as for a point source (Figure 13.4). 

In some configurations of dryers the length of zones and thus the sound intensity distribution may become important. For example, the Fresnel zone for the plane source 10 cm in diameter is negligible (couple of millimeters) for sound at 100 Hz (cf. frequency of pulse combustion) but extends for 15.6 cm in the range of ultrasound at 20 kHz and 31.2 cm at 40 kHz. 

Using the similar principle of contact imaging, an optofluidic fluorescence microscope was fabricated [6]. Here an array of Fresnel zone plates (FZP) were used to generate focused light spots inside the chip. Similar to the OFM, here the FZP is fabricated in a diagonal fashion so that all the portions of the particle can be captured by the sensor (Fig. 2b). Unlike OFM, apertures are not created over the CMOS sensor, but instead specific filters are coated over the CMOS sensor to assist in the detection of fluorescence (Fig. 2a). The performance of the microscope seemed good when compared to... 

Optofluidic Imaging Techniques, Fig. 2 (a) Schematic of the FZP-based fluorescence optofluidic microscope (FOFM) showing the focused light spots due to the FZP. (b) Top view schematics, (c) SEM image of a Fresnel zone plate (FZP). (d) Picture of the actual device signifying its size, (e-g) Fluorescence image of HeLa cells... 

Pang S et al (2011) Fluorescenee microseopy imaging with a Fresnel zone plate array based optofluidic microscope. Lab Chip ll(21) 3698-3702... 

The general shape of the bistatic pattern in the back sector is readily nnderstood by noting that the scattered field is essentially coming from the first Fresnel zone associated with the particnlar bistatic directions as shown at the top of Fig. 8.1. 

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