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Showing papers on "Zone plate published in 2005"


Journal ArticleDOI
30 Jun 2005-Nature
TL;DR: The achievement of sub-15-nm spatial resolution with a soft X-ray microscope—and a clear path to below 10 nm—using an overlay technique for zone plate fabrication is reported.
Abstract: The study of nanostructures is creating a need for microscopes that can see beyond the limits of conventional visible light and ultraviolet microscopes. X-ray imaging is a promising option. A new microscope described this week achieves unprecedented resolution, and has the ability to see through containing material. It features a specially made two-component zone plate — a lens with concentric zones rather like the rings in the Fresnel lenses familiar in overhead projectors and elsewhere — that makes use of diffraction to project an image into a CCD camera sensitive to soft X-rays. Spatial resolution of better than 15 nm is possible. Analytical tools that have spatial resolution at the nanometre scale are indispensable for the life and physical sciences. It is desirable that these tools also permit elemental and chemical identification on a scale of 10 nm or less, with large penetration depths. A variety of techniques1,2,3,4,5,6,7 in X-ray imaging are currently being developed that may provide these combined capabilities. Here we report the achievement of sub-15-nm spatial resolution with a soft X-ray microscope—and a clear path to below 10 nm—using an overlay technique for zone plate fabrication. The microscope covers a spectral range from a photon energy of 250 eV (∼5 nm wavelength) to 1.8 keV (∼0.7 nm), so that primary K and L atomic resonances of elements such as C, N, O, Al, Ti, Fe, Co and Ni can be probed. This X-ray microscopy technique is therefore suitable for a wide range of studies: biological imaging in the water window8,9; studies of wet environmental samples10,11; studies of magnetic nanostructures with both elemental and spin-orbit sensitivity12,13,14; studies that require viewing through thin windows, coatings or substrates (such as buried electronic devices in a silicon chip15); and three-dimensional imaging of cryogenically fixed biological cells9,16.

842 citations


Journal ArticleDOI
TL;DR: In this article, a Fresnel zone plate lens coupled to a single-element square-spiral-coupled infrared detector has been fabricated and its performance compared to single element antenna-couple detectors and 2-D arrays of antenna coupled detectors.
Abstract: Infrared focal plane arrays (IRFPAs) are a critical component in advanced infrared imaging systems. IRFPAs are made up of two parts, a detector array and a readout integrated circuit (ROIC) multiplexer. Current ROIC technology has typical pitch sizes of 20/spl times/20 to 50/spl times/50 /spl mu/m/sup 2/. In order to make antenna-coupled detectors suited for infrared imaging systems, two-dimensional (2-D) arrays have been fabricated that cover a whole pixel area with the penalty of increasing the noise figure of the detector and, therefore, reducing its performance. By coupling a Fresnel zone plate lens to a single element antenna-coupled detector, infrared radiation can be collected over a typical pixel area and still keep low-noise levels. A Fresnel zone plate lens coupled to a single-element square-spiral-coupled infrared detector has been fabricated and its performance compared to single element antenna-coupled detectors and 2-D arrays of antenna coupled detectors. Measurements made at 10.6 /spl mu/m showed a two-order-of-magnitude increase in SNR and a /spl sim/3/spl times/ increase in D/sup */ as compared to 2-D arrays of antenna-coupled detectors.

101 citations


Journal ArticleDOI
TL;DR: In this paper, a tantalum Fresnel zone plate with an outermost zone width of 50 nm and a thickness of 0.5 µm has been fabricated by electron-beam lithography.
Abstract: A microfocusing experiment for hard X-rays has been performed to evaluate the performance of Fresnel zone plate optics. A tantalum Fresnel zone plate with an outermost zone width of 50 nm and a thickness of 0.5 µm has been fabricated by electron-beam lithography. The focused beam size measured by a knife-edge scan is 58 nm in full-width at half-maximum for the first-order diffraction at an X-ray energy of 8 keV. It can be concluded that this zone plate has nearly diffraction-limited resolution in the hard X-ray region. The measured diffraction efficiency is 5% at 8 keV. The spot size using the third-order focus of the zone plate is measured to be approximately 30 nm.

97 citations


Journal ArticleDOI
TL;DR: Images with a spatial resolution of 120-150 nm were obtained with 46.9 nm light from a compact capillary-discharge laser by use of the combination of a Sc-Si multilayer-coated Schwarzschild condenser and a free-standing imaging zone plate.
Abstract: Images with a spatial resolution of 120–150?nm were obtained with 46.9?nm light from a compact capillary-discharge laser by use of the combination of a Sc–Si multilayer-coated Schwarzschild condenser and a free-standing imaging zone plate. The results are relevant to the development of compact extreme-ultraviolet laser-based imaging tools for nanoscience and nanotechnology.

65 citations


Journal ArticleDOI
TL;DR: In this paper, the growth and characterization of a depth-graded multilayer suitable for use as a zone plate for hard x-ray focusing was presented, which has a total of 470 alternating layers of WSi2 and Si with thicknesses increasing monotonically from 15 to 60 nm.
Abstract: Fresnel zone plates for x-ray focusing optics are typically made using lithographic techniques. To achieve optimum efficiency for hard x rays, a depth of several microns is required, which limits the minimum zone width and hence minimum focal spot size achievable using lithography. We are exploring the fabrication of zone plates by an alternative technique that surmounts these limitations: the growth of a multilayer film to be used in transmission (Laue) diffraction geometry, in which the thickness of consecutive layers gradually increases according to the Fresnel zone formula; the film is sectioned after growth to the required depth. For a planar multilayer, this produces a linear zone plate that can focus x rays in one dimension. Here we report the growth and characterization of a depth-graded multilayer suitable for use as a zone plate for hard x-ray focusing. The multilayer has a total of 470 alternating layers of WSi2 and Si with thicknesses increasing monotonically from 15 to 60 nm, for a total thic...

59 citations


Journal ArticleDOI
TL;DR: The implementation of an optical encryption method using zone plates shows that the diffraction efficiency of zone plates is relevant to the decryption process.

55 citations


Journal ArticleDOI
TL;DR: In this article, a liquid-crystal Fresnel zone plate (FZP) is fabricated by the LC molecular alignment process without the need for surface relief structures and patterned electrodes.
Abstract: A novel liquid-crystal (LC) Fresnel zone plate (FZP) is fabricated only by the LC molecular alignment process without the need for surface relief structures and patterned electrodes. It is theoretically described that the Fresnel-lens-like phase profile is achieved under optimum LC molecular orientation conditions and the polarization state of incident light, that is, the retardation of the LC cell is (n+1/2)λ (n is an integer) and the incident light is circularly polarized. The optical properties of the fabricated LC FZP are experimentally investigated. Good focusing properties are confirmed (the full width at half maximum of the spot is approximately 8% larger than that of the diffraction limit) and the light intensity of the focusing spot is found to be controllable by adjusting applied voltage.

48 citations


Journal ArticleDOI
TL;DR: In this paper, a coherent soft X-ray beam is selected with a pinhole, and the illuminated specimen is followed by an adjustable beamstop and CCD camera to record diffraction data from non-crystalline specimens.
Abstract: An apparatus for diffraction microscopy of biological and materials science specimens is described. In this system, a coherent soft X-ray beam is selected with a pinhole, and the illuminated specimen is followed by an adjustable beamstop and CCD camera to record diffraction data from non-crystalline specimens. In addition, a Fresnel zone plate can be inserted to allow for direct imaging. The system makes use of a cryogenic specimen holder with cryotransfer capabilities to allow frozen hydrated specimens to be loaded. The specimen can be tilted over a range of ± 80 ∘ for three-dimensional imaging; this is done by computer-controlled motors, enabling automated alignment of the specimen through a tilt series. The system is now in use for experiments in soft X-ray diffraction microscopy.

47 citations


Journal ArticleDOI
TL;DR: The demonstrated demonstration of reflection mode imaging of 100 nm-scale features using 46.9 nm light from a compact capillary-discharge laser advances the development of practical and readily available surface and nanostructure imaging tools based on the use of compact sources of extreme ultraviolet light.
Abstract: We report the demonstration of reflection mode imaging of 100 nm-scale features using 46.9 nm light from a compact capillary-discharge laser. Our imaging system employs a Sc/Si multilayer coated Schwarzschild condenser and a freestanding zone plate objective. The reported results advance the development of practical and readily available surface and nanostructure imaging tools based on the use of compact sources of extreme ultraviolet light.

46 citations


Journal ArticleDOI
TL;DR: Using a laser driven high-harmonic light source, optimized for having the maximum brightness at around 100 eV, a pair of multilayer mirrors to select a narrow spectral band and acting simultaneously as a condenser and a Fresnel zone plate as microscope objective, this paper was able to resolve 200 nm structures of a diatom sample.

46 citations


Patent
10 Aug 2005
TL;DR: In this paper, a fabrication process for zone plate lenses is based on controlled thin layer deposition for fabricating structures as small as 2 nanometers (nm) in width, and potentially smaller, and the substrate for deposition will take the form of a precision hole, fabricated in a substrate, such as silicon by electron beam lithography and subsequent reactive ion etching.
Abstract: A fabrication process for zone plate lenses is based on controlled thin layer deposition for fabricating structures as small as 2 nanometers (nm) in width, and potentially smaller. The substrate for deposition will take the form of a precision hole, fabricated in a substrate, such as silicon by electron beam lithography and subsequent reactive ion etching. A controlled layer deposition is then used to form the required zone plate structure. A subsequent thinning process is used to section the hole and produce a zone plate with the required layer thicknesses.

Journal ArticleDOI
11 Jul 2005-Polymer
TL;DR: In this article, narrow banded structures of spherulites of poly[( R )-3-hydroxybutyrate] (P(3HB)) and its copolymers, with different second monomer unit of 4-hydroxbutyrates, 3-hydrohexanoate or 6-hydoxyhexanoates, were investigated by microbeam X-ray diffraction with the Fresnel Zone Plate technique in synchrotron radiation (SPring-8).

Journal ArticleDOI
TL;DR: In this paper, an immersion scheme is used to improve resolution, exposure latitude, and depth-of-focus in zone-plate-array lithography (ZPAL) systems.
Abstract: An immersion scheme is used to improve resolution, exposure latitude, and depth-of-focus in zone-plate-array lithography (ZPAL). We believe this is the first implementation of an immersion scheme in a maskless lithography system. Replacing air with de-ionized water as the medium between the zone-plate array and the substrate effectively increases the system’s numerical aperture and consequently, enhances its patterning capabilities. The design and fabrication process of an immersion zone plate is described. Its behavior is then characterized through the experimental reconstruction of its point-spread function, and compared to the theoretical model. A wide variety of patterns were printed, demonstrating the improved lithographic performance of immersion ZPAL.

Journal ArticleDOI
TL;DR: In this paper, a new kind of interferometric array that yields images of high dynamic range and large field was proposed for astrophysical imaging over a broad spectral bandwidth spanning from the UV (50 nanometers) to the IR (20 µm).
Abstract: We propose a new kind of interferometric array that yields images of high dynamic range and large field. The numerous individual apertures in this array form a pattern related to a Fresnel zone plate. This array can be used for astrophysical imaging over a broad spectral bandwidth spanning from the UV (50 nanometers) to the IR (20 µm). Due to the long focal lengths involved, this instrument requires formation-flying of two space borne vessels. We present the concept and study the S/N ratio in different situations, then apply these results to probe the suitability of this concept to detect exoplanets.

Journal ArticleDOI
TL;DR: In this article, reflection zone plates and Bragg-Fresnel lenses can be used to achieve sub-nanometer spatial resolution, subject to source size limitations, by using a beamforming method.

Patent
13 Jan 2005
TL;DR: A Fresnel lens sheet comprises a fly-eye lens or prisms as a regular concavities and convexities configuration for suppressing regular reflection on the surface thereof on a side opposite to the side having the lens formed thereon as discussed by the authors.
Abstract: A Fresnel lens sheet comprises a Fresnel lens on one surface thereof, wherein respective unit surfaces constructing the Fresnel lens sheet have rough surfaces. Since it has a rough surface, it enables suppressing the occurrence of moire, when making up a screen. The other Fresnel lens sheet comprises a Fresnel lens on one surface thereof, and a fly-eye lens or prisms as a regular concavities and convexities configuration for suppressing regular reflection on the surface thereof on a side opposite to the side having the Fresnel lens formed thereon. Since it has on its rear surface a fly-eye lens or a prism, it enables suppressing the occurrence of ghost image.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the influence of the spatial coherence on the focal shift of the Fresnel zone plate and showed that focal shift is not only dependent upon the number of Fresnel numbers of the focusing system, but also on the spatial coherentness of the incident partially coherent light.

Journal ArticleDOI
TL;DR: In this article, planar, Fresnel-like microlenses are prepared by a spontaneous chemical process of periodic precipitation (PP) occurring in a thin layer of a dry gel, and initiated by wet stamping.
Abstract: Arrays of planar, Fresnel-like microlenses are prepared by a spontaneous chemical process of periodic precipitation (PP) occurring in a thin layer of a dry gel, and initiated by wet stamping. The PP lenses focus white light more efficiently than the conventional Fresnel zone plates of similar dimensions. Nanoscale topographies of the micropatterned gels can be replicated into transparent elastomers, and used for focusing based on optical path differences. Experimental observations for both types of structures are in agreement with the Fresnel diffraction calculations.

Proceedings ArticleDOI
18 May 2005
TL;DR: The phase-correcting Fresnel zone plate provides lens-like focusing and imaging of electromagnetic waves by means of diffraction instead of refraction, often referred to as diffraction optics.
Abstract: The phase-correcting Fresnel zone plate provides lens-like focusing and imaging of electromagnetic waves by means of diffraction instead of refraction, often referred to as diffraction optics The zone plate has seen extensive investigation and use at microwave and millimeter-wave frequencies, and recently has been applied in the terahertz region These cases have dealt principally with large-angle designs, where the focal length (F) and diameter (D) are comparable (F/D = 03 to 25), unlike the typical optical examples The planar zone plate, in particular, offers the advantages of simplicity of design and construction, low loss, low weight, and low cost, while giving performance similar to that of a refractive lens As one goes to terahertz frequencies, ease of construction becomes more difficult The attenuation in conventional low-loss materials increases at higher frequencies, and dimensional tolerances become smaller, making fabrication more difficult Although earlier designs employing polystyrene have been built and tested at frequencies up to 280 GHz, higher frequency designs are simpler to fabricate and have lower loss if low dielectric constant materials are used This investigation addressed designs for terahertz frequencies The optimization of the zone plate has also been examined, and improvement has been found for radial compression, where the radii of the zone boundaries are slightly shortened

Patent
30 Dec 2005
TL;DR: In this article, a focusing unit includes a Fresnel lens combination, where the Fresnel lenses are oriented to reduce shadowing losses, which is a scattering of light from reflection at the facet walls that separate adjacent Fresnel zones on a given lens.
Abstract: A focusing unit includes a Fresnel lens combination, where the Fresnel lenses are oriented to reduce shadowing losses. Shadowing is a scattering of light from reflection at the facet walls that separate adjacent Fresnel zones on a given Fresnel lens. Two substantially adjacent Fresnel lenses make up the focusing unit, which can be used as a condenser that collects light from a source in a projection system. Both Fresnel lenses have non-faceted sides that face the light source. The first Fresnel lens collimates the light from the source. The second Fresnel lens receives the collimated beam, with a range of incident angles determined by the spatial extent of the source. Components such as reflective polarizers and anti-reflection coatings can be used between the Fresnel lenses and can be applied to the non-faceted side of the second Fresnel lens.

Journal ArticleDOI
TL;DR: A diffraction field-focusing equation based on a specific conical-segment linearization procedure is derived for the Fresnel zone plate (FZP) lens of arbitrary curved profile and is applied for contrasting plane, spherical, parabolic and conical zone plate lenses, convex-side illuminated by a paraxial plane wave front.
Abstract: A diffraction field-focusing equation based on a specific conical-segment linearization procedure is derived for the Fresnel zone plate (FZP) lens of arbitrary curved profile and is applied for contrasting plane, spherical, parabolic and conical zone plate lenses, convex-side illuminated by a paraxial plane wave front. Two sets of 100-GHz curvilinear and plane FZP lenses are studied numerically with regards to their dimensions, axial focusing intensity and footprint, and frequency bandwidth. For the first set , where the curvilinear and plane lenses share a common lens base aperture and have equal focal lengths, the following new finding has resulted: regardless of their different in shape profiles the FZP lenses have equal zone numbers and produce similar axial focusing. The second set also consists of plane, spherical, parabolic and conical lenses. They share a common apex, and have equal in diameter base apertures and focal lengths but different thicknesses. For such disposition and proportions, the FZP lenses possess different zone numbers and focusing parameters (gain, efficiency, footprint and bandwidth). The belief that the curvilinear FZP have superior (or inferior) electromagnetic characteristics, compared to those of the plane FZP lens with equal number of zones is not in general true. Their relative focusing qualities can vary significantly depending on the lens positioning and dimensions.

Journal ArticleDOI
TL;DR: In this article, an optical system consisting of an x-ray objective lens (Fresnel zone plate) and a wave front-division-type interferometer with prism optics was developed and preliminary experiments have been done at SPring-8 undulator beamline 20XU.
Abstract: An optics for hard x-ray holographic microscopy has been developed and preliminary experiments have been done at SPring-8 undulator beamline 20XU. The optical system consists of an x-ray objective lens (Fresnel zone plate) and a wave front-division-type interferometer with prism optics. The illuminating x-ray beam is coherent with parallel radiation, and the spatially coherent area is much larger than the aperture of the objective lens. The refractive prism is placed behind the back focal plane of the objective lens in order to configure the wavefront-dividing interferometer. Half of the illuminating radiation is used for illuminating an object, and the other half is used for forming a reference wave. The magnified image of the object is generated at an image plane, and the reference wave is superimposed on the magnified image of the object. The recorded interferogram includes both amplitude and phase information of the object. The spatial resolution is determined by the numerical aperture of the objective lens. Therefore, in principle, this method enables holographic imaging at nanometer scale to be carried out in the hard x-ray region.

Patent
27 Jan 2005
TL;DR: In this article, a light-reflecting layout material has lines, each line incorporating at least two strings of lightreflecting elements installed in layout material; each light reflecting element is made in the form of at least part of lens, zone plate, Fresnel lens, or their parts in all respective lines.
Abstract: FIELD: light-reflecting layout materials. ^ SUBSTANCE: proposed layout material has lines, each line incorporating at least two strings of light-reflecting elements installed in layout material; each light-reflecting element is made in the form of at least part of lens or at least part of phase zone plate, or at least part of Fresnel lens made of material whose reflective index is higher by at least 3% than that of layout material, or it may have reflecting layer applied to rear surface of each lens, zone plate, Fresnel lens, or their parts to produce pattern of respective lens, zone plate, Fresnel lens, or their parts above their respective front surfaces; all strings of lenses, zone plates, Fresnel lenses, or their parts in all respective lines are installed in layout material in common vertical and/or horizontal plane. ^ EFFECT: enhanced descriptiveness, enlarged functional capabilities, and improved appearance. ^ 32 cl, 9 dwg

Proceedings ArticleDOI
07 Feb 2005
TL;DR: In this article, a fast algorithm using the host Fresnel zone plate was proposed to improve the computational efficiency of computer-generated hologram (CGH) for 3D objects, where the spatial position information of each point of the 3D object was obtained directly.
Abstract: A new fast algorithm using the “host” Fresnel zone plate was proposed to improve the computational efficiency of computer-generated hologram (CGH) for 3D objects. By reading .3DS files, the spatial position information of each point of the 3D object was obtained directly. With the illumination of plane wave, the “host” Fresnel zone plate of a single point could be equal to all points located in the same depth plane - as the Fresnel zone plate was translated and superimposed along the horizontal and vertical axes. Consequently, the hologram of a 3D object could be built up by superimposing different Fresnel zone plates in the corresponding depth planes. For a digital object composed of 1060 points, it cost about 83s to generate a hologram of 1024*768 pixels. The CGH of 3D objects with the results of the reconstruction was presented in this paper, which proved the feasibility of this algorithm.

Journal ArticleDOI
TL;DR: Three most important advantages of the proposed moiré zone plates are: a constant aperture of the created element during the mutual movement of basic grids, lack of aberrations due to their undesired mutual lateral displacements and high diffraction efficiency of the binary phase version.
Abstract: We present equilateral hyperbolic zone plates with variable focal length, which are formed as moire patterns by a mutual rotation of two identical basic grids. Among others, all principal zone plates, except of the spherical one, can be used as these basic transmittances. Three most important advantages of the proposed moire zone plates are: a constant aperture of the created element during the mutual movement of basic grids, lack of aberrations due to their undesired mutual lateral displacements and high diffraction efficiency of the binary phase version. To obtain clearer moire fringe pattern, a radial carrier frequency can be added additionally to the transmittances of basic grids. The destructive interference between both arms of the focal cross of the equilateral hyperbolic moire zone plate can be obtained by a constant phase shift introduced in the transmittances of the basic grids. Potential applications of discussed elements are indicated, including the most promising one in the three-point alignment technique.

Proceedings ArticleDOI
01 Jan 2005
TL;DR: The existence of a free parameter in the design of Fresnel zone plates can be chosen to have non-standard values which are shown to improve important aspects of antenna performance and to add new functionality to zone plate antennas.
Abstract: We call attention to the existence of a free parameter in the design of Fresnel zone plates. Historically, zone plates have been designed with a specific choice for this parameter, which can be taken as a type of phase reference. We present two methods of interpreting the parameter, either in terms of a reference radius or equivalently a reference phase. Importantly, the parameter can be chosen to have non-standard values which are shown to improve important aspects of antenna performance and to add new functionality to zone plate antennas

Patent
22 Nov 2005
TL;DR: In this paper, a single light source-compatible Fresnel lens sheet for a transmission type screen, comprising a base material sheet and a lens part, was constructed on the base material, and a relation between the haze value H (%) and the thickness T (mm) at a Fresnel center part was established.
Abstract: A single light source-compatible Fresnel lens sheet for a transmission type screen, comprising a base material sheet (11) and a Fresnel lens part (12) formed on the base material sheet (11). A relation between the haze value H (%) and the thickness T (mm) of the Fresnel lens sheet (10) at a Fresnel center part (14) fulfills the requirement of the expression below. H ≥ 3.15T3 - 23.6T2 + 63.8T - 20.5 ... 1

Proceedings ArticleDOI
TL;DR: The photon sieve as discussed by the authors is a flat diffractive element which requires no out-of-plane deformation and is thus much simpler to deploy than the Fresnel zone plate.
Abstract: The creation of next generation, ultra-large space telescopes (>20m diameter) will require novel technologies. Many current concepts involve curved membrane reflectors but the problem is creating a diffraction-limited, three-dimensional surface. Here we present the idea of using a flat diffractive element which requires no out-of-plane deformation and is thus much simpler to deploy. The primary is a photon sieve--a diffractive element consisting of a large number of precisely positioned holes distributed over a flat surface. Photon sieves can be simply designed to any conic, apodization and operating bandwidth. The photon sieve is easier to fabricate than the better known Fresnel zone plate as a single substrate can be used since there are no connected regions requiring support. Presented here are results of prototypes capable of diffraction-limited imaging over wide fields and useful bandwidths.

Journal ArticleDOI
TL;DR: In this article, an analytical expression based on an improved Rayleigh-Sommerfeld diffraction formula with evanescent term is derived for analyzing the axial light intensity distribution throughout the whole space behind a Fresnel zone plate.
Abstract: An analytical expression based on an improved Rayleigh–Sommerfeld diffraction formula with evanescent term is derived for analyzing the axial light intensity distribution throughout the whole space behind a Fresnel zone plate. The effects of the number of Fresnel zones and the size of aperture on the axial intensity distribution are calculated for two kinds of Fresnel zone plate with larger and smaller aperture. The validity of the general formulae for calculating the focal lengths and the relative intensities of the foci of a Fresnel zone plate is analyzed.

Journal ArticleDOI
TL;DR: In this paper, a multiphase Fresnel zone plate was used to improve the resolution of near-field optical system with a solid immersion lens by using scalar angular spectrum theory, which can not only decrease the spot size but also decrease the sidelobe intensity and enhance greatly the diffractive efficiency.
Abstract: We propose a method to improve the resolution of near-field optical system with a solid immersion lens by using a multiphase level Fresnel zone plate. The analyses are based on scalar angular spectrum theory. The results show that the multiphase Fresnel zone plate can not only decrease the spot size but also decrease the sidelobe intensity and enhance greatly the diffractive efficiency compared with annular amplitude filter or binary 2-, 3-, 4-zone phase filter.