Showing papers on "Zone plate published in 1995"
TL;DR: In this article, a new variety of millimeter-wave Fresnel-zone plate lens with enhanced focusing quality is described, where each full-wave zone of the lens is divided into four quarter-wave subzones, which are covered by dielectric rings having equal thickness but different permittivities.
Abstract: A new variety of millimeter-wave Fresnel-zone plate lens with enhanced focusing quality is described Each full-wave zone of the lens is divided into four quarter-wave subzones, which are covered by dielectric rings having equal thickness but different permittivities More practical equations are derived for the radii of the zones, and for the thickness of the lens by taking into account the angle of incidence of the electromagnetic wave A Fresnel-zone plate antenna (FZPA) consisting of a quarterwave lens and a scalar feed is developed and analysed theoretically Equations for the aperture field and far field are derived using multiple ray tracing through dielectric plates and vectorial Kirchhoff diffraction theory, respectively It is demonstrated that the proposed transmissive-type FZPA has an aperture efficiency of more than 50% in the 60 GHz frequency band This computed efficiency agree with the measured overall efficiency reported by other researchers for an X-band quarter-wave reflector-type FZPA
114 citations
TL;DR: In this paper, a high resolution cross-linked PMMA resist has been synthesized and optimized for the generation of zone plate patterns down to 19 nm linewidth with e−beam lithography.
Abstract: A high resolution cross‐linked PMMA resist has been synthesized and optimized for the generation of zone plate patterns down to 19 nm linewidth with e‐beam lithography. This resist shows an increased resolution compared to PMMA for generating periodic structures with a line to space ratio of 1:1. Furthermore, we developed a cross‐linked copolymer based on styrene and divinylbenzene, which is used in a new trilevel reactive ion etching (RIE) process. In this process a resist pattern of low aspect ratio can be transferred into a copolymer galvanoform with high aspect ratios for the electrodeposition of nickel. The copolymer has also been used as a highly selective etching mask for zone plate pattern transfer into germanium by RIE.
84 citations
TL;DR: The ESCA microscopy beamline as mentioned in this paper is dedicated to high spatial resolution quantitative and qualitative analysis on surfaces and interfaces, with a spatial resolution of ∼0.1 μm.
Abstract: The article describes the ESCA microscopy beamline dedicated to high spatial resolution quantitative and qualitative analysis on surfaces and interfaces. The scanning microscope is constructed to work both in transmission and photoemission within the photon energy range from 200 to 1200 eV with a spatial resolution of ∼0.1 μm. A Fresnel zone plate demagnifies the photon beam to submicrometer dimensions with 109–1010 photons/s in the focus spot. A photodiode and a hemispherical electron energy analyzer are used as detectors for recording the transmitted x‐rays and emitted photoelectrons, respectively. The operation modes in photoemission give the opportunity to obtain conventional energy distribution curve spectra from a microspot or a two‐dimensional micrograph of the spatial distribution and local concentration of a selected element as the sample is mechanically scanned. For conductive specimen topography measurements of a selected surface area probed by SPEM are possible using a scanning tunnelling microscope. The first test images of a zone plate and an e‐beam written specimen with 1 μm2 Au squares on Si have shown a spatial resolution better than 0.2 μm.
71 citations
TL;DR: In this paper, a new computational approach is suggested to the analysis of imaging properties of realistic X-ray Fresnel zone plates with high aspect ratio, based on the parabolic wave equation (PWE) describing diffraction inside the zone plate body as well as wave propagation and focusing throughout the optical system.
71 citations
TL;DR: In this article, a zone-plate microscope at beamline 6.1 of the ALS was used for high-resolution zone-plating at synchrotron radii.
Abstract: (1995). New high‐resolution zone‐plate microscope at beamline 6.1 of the ALS. Synchrotron Radiation News: Vol. 8, No. 3, pp. 29-33.
56 citations
TL;DR: In this paper, a planar Fresnel-zone antenna for DBS-reception with more than 50% aperture efficiency was developed and examined theoretically, where each full-wave zone is divided into four quarter-wave subzones, which are covered by dielectric rings having equal thickness but different permittivities.
Abstract: A new variety of the Fresnel zone planar lens with enhanced focusing quality is proposed. Each full-wave zone is divided into four quarter-wave subzones, which are covered by dielectric rings having equal thickness but different permittivities. Based on this planar lens configuration, a transmissive-type Fresnel-zone antenna for DBS-reception with more than 50% aperture efficiency is developed and examined theoretically. >
56 citations
TL;DR: In this paper, a hard x-ray imaging microscope based on a phase zone plate has been developed and tested, which can be used to obtain nearly diffraction-limited resolution over the entire imaging field and its resolution is almost independent of source size and source motions.
Abstract: A hard x‐ray imaging microscope based on a phase zone plate has been developed and tested. The zone plate, with a 5 cm focal length and a 0.2 μm smallest linewidth, was used to image 8 keV x rays from the samples. The imaging microscope can be used to obtain nearly diffraction‐limited resolution over the entire imaging field, and its resolution is almost independent of source size and source motions. We have tested such an imaging microscope, and a resolution of about 0.4 μm was obtained. The images were obtained with an exposure time of less than 1 min, for a magnification factor of 30 in the x rays. The x rays were then converted into visible light, and another 7 times magnification were obtained by using a lens system coupled to a charge coupled device camera. The results from the imaging microscope, and possible applications, will be discussed.
52 citations
TL;DR: In this paper, a diffractive element composed of a binary phase zone-plate array is proposed to condition the intensity distribution in the focal plane of a conventional refractive lens to generate a flattop intensity envelope on target.
Abstract: We report on the theory and development of a diffractive element composed of a binary phase zone-plate array. This component conditions the intensity distribution in the focal plane of a conventional refractive lens to generate efficiently (82%) a flattop intensity envelope on target. Analysis of the design indicates that manufacturing tolerances are not critical. Experimental performances on target from x-ray emission and shock-breakout measurements are also presented.
48 citations
TL;DR: In this paper, an explanation for interference observed at the focal point of regular X-ray capillary lenses is given, compared with the optics of Fresnel zone plates, and a comparison of the two types of lenses is made.
44 citations
TL;DR: In this paper, an instrument that combines the techniques of x-ray photoelectron spectroscopy and zone plate microfocusing to perform spectromicroscopy was developed.
Abstract: We have been developing an instrument that combines the techniques of x‐ray photoelectron spectroscopy and zone plate microfocusing to perform spectromicroscopy. The X1A undulator provides a bright photon source in the soft x‐ray range with a high degree of spatial coherence (a requirement for zone plate focusing). A spherical grating monochromator selects the desired photon energy in the 280–800 eV range. A Fresnel zone plate focuses the beam to a small spot. Photoelectron spectra can be acquired from the small irradiated area with an electron energy analyzer. With the beam focused on the surface and the sample mechanically scanned, element‐specific or chemical‐state‐specific images of the surface can be obtained.
29 citations
TL;DR: In this paper, a sputtered-sliced hard x-ray zone plate has been made by the physical vapor deposition of alternating transparent and opaque layers onto a fine gold wire core of 50 μm diameter.
Abstract: A sputtered‐sliced hard x‐ray zone plate has been made by the physical vapor deposition of alternating transparent and opaque layers onto a fine gold wire core of 50 μm diameter The zone plate is designed to operate with a focal length of 124 mm at 805 eV and consists of 25 pairs of alternating Ag and C layers with a thickness of ∼40 μm along the wire axis Using monochromized synchrotron x ray with an energy of 805 keV the minimum focal spot size attained for the first order focal beam was 23 μm in the vertical and horizontal directions, respectively The light‐collecting efficiency was determined to be ∼4% The focal spot size obtained was substantially larger than the 12 μm φ spatial resolution predicted from the contradiction of the light source size
TL;DR: In this paper, an e-beam tool consisting of a commercial pattern generator and a scanning electron microscope is used for the fabrication of high-resolution zone plates for x-ray microscopy applications.
Abstract: In this work, an e‐beam tool consisting of a commercial pattern generator and a scanning electron microscope is used for the fabrication of high‐resolution zone plates for x‐ray microscopy applications. In order to avoid misplacement of the zone plate structures, which would result in a deterioration of the imaging properties, various possible distortions of the lithography system are investigated. Misscaling and nonorthogonality of the deflection axes are eliminated by a simple alignment routine using contamination marks. Drift is found to be sufficiently small after several hours of thermal stabilization. The nonlinearity error is measured by the exposure of Moire patterns. We were able to reduce the total misplacement of the zone plate structures to less than 3×10−4 of the zone plate’s diameter. The resist patterns can be transferred in germanium and tantalum by reactive ion etching using trilevel processes resulting in structures with linewidths down to 26 nm. The quality of the dry etching process is shown by measurement of the x‐ray diffraction efficiency. Imaging an e‐beam‐generated test object with the fabricated zone plates at λ=2.4 nm proves that the total distortions of the e‐beam tool were sufficiently reduced.
TL;DR: In this article, a wave front measuring interferometer at 12-13 nm wavelength was used to measure the aberrations in 0.1 numerical aperture Fresnel zone plate lenses.
Abstract: Diffraction‐limited optical imaging systems for extreme ultraviolet (EUV) lithography require wave front aberrations to be limited to a fraction of the EUV wavelength. Surface figure metrology and wave front measurement at this level of accuracy represent key challenges in the development of EUV lithography. We have constructed and operated a wave front measuring interferometer at 12–13 nm wavelength. This interferometer is being used to measure the aberrations in 0.1 numerical aperture Fresnel zone plate lenses. Factors limiting the resolution and accuracy of the interferometer were studied. Substantial progress toward λ/20 wave front measurement accuracy has been made.
TL;DR: In this article, a multilayer zone plate with a crystal is used as a monochromatizing and focusing device for hard X-rays, i.e., a Bragg-Fresnel lens.
Abstract: Multilayer zone plates whose outermost zone widths are less than 100 nm have been fabricated. Alternate deposition of Ag and Al layers has been performed using a helicon plasma sputtering technique, in which Ar gas pressure was less than 1×10-3 Torr, which is one order lower than in conventional magnetron sputtering. More than 100 Ag/Al layers were deposited, with the thickness of each layer being monitored and controlled by a computer. The multilayered plane was sliced vertically and thinned after the deposition. The multilayer zone plate combined with a crystal acts as a monochromatizing and focusing device for hard X-rays, i.e., a Bragg-Fresnel lens.
Patent•
29 Jun 1995TL;DR: In this article, an apparatus of an objective lens for guiding an exposure beam emitted by a light source toward a first region on a rotary table, a lighting light source for irradiating lighting light in the direction of the first region via the objective lens, an image pickup device for picking up an image from the first obtained via the lens, modulation means for changing the propagating direction of exposure beam, and a controller for controlling the modulation means on the basis of a signal input from the image pickup devices.
Abstract: An apparatus of this invention has an objective lens for guiding an exposure beam emitted by a light source toward a first region on a rotary table, a lighting light source for irradiating lighting light in the direction of the first region via the objective lens, an image pickup device for picking up an image from the first region obtained via the objective lens, modulation means for changing the propagating direction of the exposure beam, and a controller for controlling the modulation means on the basis of a signal input from the image pickup device.
TL;DR: In this paper, a vectorial far field analysis of the Fresnel-zone plate antenna (FZPA) is presented using two different calculation methods: Physical Optics and Uniform Theory of Diffraction Expressions.
Abstract: A vectorial far-field, analysis of the Fresnel-zone plate antenna (FZPA) is presented using two different calculation methods The first method, Physical Optics, is based on Kirchhoff's diffraction theory and holds for apertures which are large in terms of the wavelength Because this is not the case for the width of all the radiating rings of the FZPA, a second method is used which accounts for the influence of the edges of the rings on the incident field This method is based on a combination of the Geometrical Theory of Diffraction and the Uniform Theory of Diffraction Expressions which describe the radiation patterns are derived using both methods, and the differences and similarities between them are examined The results of this analysis give good insight into the influence of the FZPA geometry on its radiation properties
TL;DR: A simple analysis of these binary phase zone plates using diffraction theory is presented and used both to optimise the uniformity of the focal spot by modifying the Fresnel zone structure and to produce noncircular foci as discussed by the authors.
TL;DR: In this article, an electromagnetic analysis of diffraction by Fresnel linear zone plates ruled into a homogeneous or a stratified media is developed, taking advantage of the new possibilities brought by the R-matrix propagation algorithm into the theory of lamellar gratings, namely, the large increase of the stability domain of numerical results.
Abstract: An electromagnetic analysis of diffraction by Fresnel linear zone plates ruled into a homogeneous or a stratified media is developed. It takes advantage of the new possibilities brought by the introduction of the R-matrix propagation algorithm into the theory of lamellar gratings, namely, the large increase of the stability domain of the numerical results. Thus a linear Fresnel zone plate can be delt with as a period of such a grating, and the diffracted field can be computed for both TE and TM polarizations. Numerical examples show the convergence of the method and study the focusing properties of positive and negative zone plates. The influence of different parameters such as incidence or number of lines is pointed out.
TL;DR: In this article, a phase Fresnel zone plate for two-dimensional X-ray focusing at grazing incidence was fabricated, and a 4 × 1 μm2 Xray source image was obtained for wavelength λ = 1.54 A.
20 Apr 1995
TL;DR: An optical two by two exchange bypass module formed by a combination of static and dynamic Fresnel zone lenses is proposed in this paper, where two types of elements are designed, to operate at wavelengths of 1.52 and 0.633 micrometers.
Abstract: An optical two by two exchange bypass module formed by a combination of static and dynamic Fresnel zone lenses is proposed. The basic concept of this switching element is to cascade pairs of dynamic Fresnel zone lenses and pairs of static Fresnel zone lenses, located on each side of a 1.5 mm thick quartz-glass substrate. Two types of elements were designed, to operate at wavelengths of 1.52 micrometers and 0.633 micrometers . The dynamic Fresnel zone lenses on the frontside of the substrate are off-axis lenses which are made switchable by filling them with a liquid crystal after covering the Fresnel structure with a transparent electrode. The second electrode is deposited on a face down mounted cover-glass. The static lenses on the backside of the substrate are conventional on-axis Fresnel zone lenses. The dynamic and the static Fresnel zone lenses, whose blazed profiles have been approximated by multi-levels, have been fabricated by means of micro-structuring techniques. Static and dynamic, on-axis and off-axis Fresnel zone lenses with different focal lengths and of different circular diameters ranging from 0.2 mm to 2.0 mm have been realized. The measured spot-sizes of the Fresnel zone lenses were close to eighth diffraction limited values and the diffraction efficiency of the eight-level lenses was higher than 80%. The switching times of the dynamic lenses were in the range of several milli-seconds and the switching contrast was about 1:10.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this paper, a modification of the spiral zone plate is proposed to decrease the central dark spot in the focus of the zone plate by introducing the π-phase jump around the circle at a properly chosen radius.
20 Apr 1995
TL;DR: In this paper, a method for uniform top-hat intensity focal spot profiles obtained from Fresnel binary phase zone plate (PZP) arrays of various designs is presented. But, the intensity envelopes have in general been of a sinc form rather than ''top-hat''.
Abstract: Binary-phase optics have been used by a number of high-power laser laboratories in order to achieve relatively smooth focal spots. However, the intensity envelopes have in general been of a sinc form rather than `top-hat.' This paper presents work on the production of uniform `top-hat' intensity focal spot profiles obtained from Fresnel binary phase zone plate (PZP) arrays of various designs. Phase plates are used to generate large area smooth focal spots and both theoretical and experimental focal spots are presented. These demonstrate the flexibility of this technique which provides a simple method of generating both uniform `top-hat' intensity profiles and spatially shaped foci, for use with high-power lasers.
25 Sep 1995
TL;DR: Lithographic techniques for fabrication of hard x-ray Fresnel zone plates are discussed in this paper, where the results achieved at the Center for X-ray Lithography of the University of Wisconsin- Madison are presented.
Abstract: Lithographic techniques for fabrication of hard x-ray Fresnel zone plates are discussed. Practical results achieved at the Center for X-ray Lithography of the University of Wisconsin- Madison are presented. Fabrication technology includes replication of an e-beam written master mask into a thick photoresist by synchrotron radiation x-ray lithography, and subsequent electroplating of a metal zone plate structure using photoresist pattern as a mold.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
04 Apr 1995
TL;DR: In this paper, the authors analyzed the FZPA with absorbing rings for both linear and circular polarization and showed that for the latter, a squint of the antenna beam is expected, because of the asymmetric antenna geometry.
Abstract: The growing number of direct broadcast satellites (DBS) asks for simple, low-cost home receiving systems. The use of the Fresnel-zone plate antenna (FZPA), which is related to the optical lens, is also promising for this application. The aperture of the FZPA is plane and its structure is determined by the well-known Fresnel ellipsoids. In a practical situation the Fresnel zones are often attached to a window of a building. Then, the line between satellite and receiver is not perpendicular to the aperture and, consequently, the rings become elliptical. In the paper this elliptical FZPA is analysed for both linear and circular polarization. The latter is included because most of the future DBS will transmit circularly polarized waves. For this particular polarization a squint of the antenna beam is expected, because of the asymmetric antenna geometry. Kirchhoff's diffraction theory is used to calculate the mainlobe, the first sidelobe and the corresponding crosspolar lobes of elliptical FZPAs with absorbing rings.
Patent•
30 Oct 1995
TL;DR: In this article, the authors describe the X-ray fluorescence microscopy process in which a pulsed pinched plasma is excited by laser to produce X-rays to analyse a sample having at least one chemical element.
Abstract: X-ray fluorescence microscopy process in which a pulsed pinched plasma is excited by laser to produce X-rays (11) to analyse a sample (12) having at least one chemical element. X- ray fluorescent radiation is emitted from the sample and by means of a Fresnel zone plate (15) or another similar X-ray optical imaging system, which has been adjusted to the wavelength of the element to be examined, forms an image on an X-ray sensitive detector (14). The exciting radiation (11) has a wavelength which is just below a maximum (resonance) absorption wavelength.
19 May 1995
TL;DR: In this paper, a prototype EUV point diffraction interferometer is presented, which is capable of performing wavefront measurement of EUV optical elements at their operational wavelength at their optical elements with wavefront aberrations limited to a fraction of an EUV wavelength.
Abstract: Optical systems for extreme ultraviolet (EUV) lithography require optical elements with wavefront aberrations limited to a fraction of an EUV wavelength to achieve diffraction-limited performance. Achieving wavefront and surface figure metrology at this level of accuracy is one of the key challenges in the development of EUV lithography. We have successfully built and operated a prototype EUV point diffraction interferometer which is capable of performing wavefront measurement of EUV optical elements at their operational wavelength. Initial experiments to characterize the interferometer, and to measure the optical wavefront diffracted from a Fresnel zone plate lens are discussed.
TL;DR: A scanning x-ray microscope using circularly polarized radiation has been constructed at the beamline NE1B of the 6.5 GeV TRISTAN accumulation ring (AR).
Abstract: A scanning x‐ray microscope using circularly polarized radiation has been constructed at the beamline NE1B of the 6.5‐GeV TRISTAN accumulation ring (AR). It uses a Fresnel zone plate as an x‐ray focusing lens. Its spatial resolution has been evaluated to be ∼1.2 μm at the energy of 933 eV. Depending on the relative orientation between the photon spin and the local magnetization direction, the magnetic domains recorded in a piece of videotape have been successfully observed visually at the L2,3 absorption edges of cobalt. The contrast of the image arises from the magnetic circular dichroism in core‐level photoemission of ferromagnets. The observed contrast was certainly reversed between L2 and L3 edges.
TL;DR: In this paper, a new method is proposed for obtaining spatially resolved multicharged ion spectra of microplasma sources with resolution better than 0.5 μm, based on making a Bragg-Fresnel lens structure on a mica crystal surface.
Abstract: A new method is proposed for obtaining spatially resolved multicharged ion spectra of microplasma sources with resolution better than 0.5 μm. The method is based on making a Bragg–Fresnel lens structure on a mica crystal surface. The lens was formed in a direction normal to the direction of dispersion and was used for the investigation of plasma created in nanosecond X pinch. The method may be used in studies of plasma heated by pico‐ and femtosecond laser radiation.
Patent•
26 Apr 1995
TL;DR: In this paper, a solid-state image pickup device with a lens structure ideal for improving sensitivity and which can form it stably and its manufacturing method is presented. But it does not specify a manufacturing method.
Abstract: PURPOSE: To provide a solid-state image pickup device which has a lens structure ideal for improving sensitivity and which can form it stably and its manufacturing method. CONSTITUTION: This is a solid-state image pickup device 11 having a light- receiving part 3 which performs photoelectric conversion and a shielding film 6 provided without covering a light receiving face 3a of the part 3. A flattening transparent layer 8 is provided over the light receiving face 3a. A lens part 12 which comprises a diffraction grating and which is in the shape of a zone plate concentrating light onto the light receiving face 3a is provided on top of the flattening transparent layer 8. The lens part 12 is made up of, for example, a Fresnel zone part. COPYRIGHT: (C)1996,JPO
TL;DR: In this article, a soft x-ray microscope has been developed at the beamline NE1B of the 6.5 GeV TRISTAN Accumulation Ring (AR), which makes use of undulator radiation as its source and a zone plate with the outermost zone width of 50 nm as its imaging element.
Abstract: A soft x‐ray microscope has been developed at the beamline NE1B of the 6.5‐GeV TRISTAN Accumulation Ring (AR). It makes use of undulator radiation as its source and a zone plate with the outermost zone width of 50 nm as its imaging element. It has two main features. First, the undulator radiation is monochromatized by a grazing incidence grating monochromator to match to the monochromaticity requirement of the zone plate. Second, a visible light prefocus unit consisting of two objectives has been designed and installed in the x‐ray microscope. The x‐ray optical system of the microscope can be adjusted easily, quickly, and precisely by using this unit. The microscope can resolve 55‐nm lines and spaces in a zone plate test pattern.