Fresnel zone plates

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. 

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. 

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... 

Soft X-ray transmission scanning microscope Scanning transmission X-ray microscopes (STXRM) for soft X-rays use Fresnel zone plates as high-resolution objectives to form a focused spot. Scanning microscopes require coherent illumination and are... 

Fig. 1.30 Fabricated Fresnel zone plate, (a) SEM image, (b) Relation between the order of rings and the contrast. Zigzag lines A and B represent the contrasts of the Fresnel zone plates made by phonon-assisted and conventional adiabatic lithography, respectively...

Fig. 1.31 Two-dimensional array of 7 x 7 Fresnel zone plates, (a) Patterns on the photomask.

FIGURE 14 Fresnel zone plate (hologram due to a point object). 

Figure 5.10 illustrates the fabrication of the Fresnel lens. The key element is the photomask with transparent odd zones and opaque even zones. The photomask was produced by etching a chromium oxide layer using electron beam lithography. The radius rj of the innermost zone was 5.5 mm and the radius of the nth zone (r ) was given by = nr, where n is the zone number. The Fresnel zone plate consisted of 80 zones in a 1 cm aperture. 

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