Showing papers on "Zone plate published in 1988"
TL;DR: A scanning soft x-ray microscope has been built and operated at the National Synchrotron Light Source as discussed by the authors, which makes use of a mini-undulator as a bright source of 3.2-nm photons.
Abstract: A scanning soft x‐ray microscope has been built and operated at the National Synchrotron Light Source. It makes use of a mini‐undulator as a bright source of 3.2‐nm photons. An electron beam fabricated Fresnel zone plate focuses the beam onto the specimen, which is scanned under computer control. The scanning stage can be moved by both piezoelectric transducers and stepping motors, and the location is monitored by a high‐speed laser interferometer. X rays transmitted through the specimen are detected using a flow proportional counter. Images of biological specimens and of artificial microstructures have been made with resolution in the 75–100‐nm range. Acquisition time for 256×256‐pixel images is about 5 min.
99 citations
Patent•
27 May 1988
TL;DR: A liquid crystal lens includes a liquid crystal cell formed by lens component members, at least one of the component members being formed of a Fresnel lens whose surface is formed by a number of annular ring-shaped Fresnel grooves with their crests leveled as discussed by the authors.
Abstract: A liquid crystal lens includes a liquid crystal cell formed by lens component members, at least one of the lens component members being formed of a Fresnel lens whose surface is formed by a number of annular ring-shaped Fresnel grooves with their crests leveled.
92 citations
TL;DR: An antenna consisting of a flat printed reflector and a feed horn was investigated at mm-wave frequencies in this paper, where the dielectric material is fully metal covered at the side opposite to the feed, whereas the side facing the feed is provided with a number of metallic annular rings forming a Fresnel zone plate.
Abstract: An antenna consisting of a flat printed reflector and a feed horn was investigated at mm-wave frequencies. The dielectric material is fully metal covered at the side opposite to the feed, whereas the side facing the feed is provided with a number of metallic annular rings forming a Fresnel zone plate. >
53 citations
TL;DR: In this article, a thermal infrared sensing array based on integrated silicon thermopiles and fabricated by using standard silicon planar technology and silicon micromachining is presented, each element of the array consists of a 10.um thick cantilever beam with one half covered by an absorbing layer and the other half containing a p-Si/Al thermopile.
41 citations
TL;DR: In this paper, a zone plate for 8 keV X-rays with alternative WSi2 and C layers was fabricated using a DC planer magnetron sputtering, and the zone plate had 20 pairs of a high aspect ratio for hard X-ray.
Abstract: A zone plate for 8 keV X-rays with alternative WSi2 and C layers was fabricated using a DC planer magnetron sputtering. The zone plate had 20 pairs of a high aspect ratio for hard X-rays. Its thickness was about 50 µm. An X-ray interference pattern through the zone plate was observed using monochromated synchrotron X-rays, and a focusing property of the zone plate was confirmed. The focal length was about 67 mm and the spot size (FWHM) was smaller than 8 µm.
36 citations
TL;DR: In this paper, the authors analyzed the effect of the distortions on the properties of a superimposed zone plate with common types of pattern inaccuracies, such as ellipticity, radial displacement, and nonconcentricity.
Abstract: Moire patterns obtained from superimposed zone plates with common types of pattern inaccuracies are analyzed. Tolerances for the distortions characterized as ellipticity, radial displacement, and nonconcentricity of the zones, are obtained from the corresponding equations for lenses. The formulas for moire fringes resulting from superimposed zone plate patterns having these defects are derived. The feasibility of moire pattern techniques to detect and measure inaccuracies of the zone plate is demonstrated. The sensitivity and the limitations of the method are discussed.
32 citations
Patent•
16 Nov 1988TL;DR: A diffractive bifocal eye lens, an otpical system, and processes for fabrication of such lenses are disclosed in this article, which includes a laser for emission of ultraviolet light along the optical axis; a zone plate mask in the path of irradiation by the laser; and an imaging lens to project, with radiation from the laser, an image of the mask on the concave inner surface of an eye lens mounted coincident with the image surface of the optical system.
Abstract: A diffractive bifocal eye lens, an otpical system, and processes for fabrication of such lenses are disclosed. The optical system includes the following principal elements in optical alignment along an optical axis, for accomplishing the indicated steps of the process: a laser for emission of ultraviolet light along the optical axis; a zone plate mask in the path of irradiation by the laser; and an imaging lens to project, with radiation from the laser, an image of the mask on the concave inner surface of an eye lens mounted coincident with the image surface of the optical system, thereby ablating the eye lens imagewise of the mask to generate a phase zone plate on the eye lens. The laser beam scans the zone plate mask to generate a composite image on the image surface. Alternatively, the phase zone plate is generated on the concave surface of a glass blank at the image surface to form a tool from which molds, and in turn lenses, are replicated. The light source is an argon fluoride excimer laser, emitting at 193 nm. The lens is a variable magnification lens to project various size images of the mask for producing zone plates of various powers as desired.
23 citations
01 Apr 1988-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: Fresnel zone plate lenses with feature sizes as small as 50 nm have been constructed and used in the Stony Brook/NSLS scanning X-ray microscope with 3.1 nm radiation from Brookhaven's X-17 mini-undulator as discussed by the authors.
Abstract: Fresnel zone plate lenses with feature sizes as small as 50 nm have been constructed and used in the Stony Brook/NSLS scanning X-ray microscope with 3.1 nm radiation from Brookhaven's X-17 mini-undulator. The zone plates were fabricated at IBM using electron beam writing techniques, moire pattern techniques to monitor ellipticity, and a double development/double plating technique to provide additional thickness in the central region. A spatial resolution down to 75 nm was measured in the microscope. Using these zone plates, biological images were obtained of unaltered subcellular components. The images highlight protein concentration in unsectioned, unfixed, and unstained enzymatic granules in an aqueous environment.
22 citations
TL;DR: Blazed zone plates have been manufactured by recording in photoresist the circular fringes transmitted by a Fabry-Perot interferometer as discussed by the authors, where the fringe pattern is scanned through one order by an axial translation of one of the mirrors and a series of exposures is recorded in such a way that a triangular groove profile is generated.
Abstract: Blazed zone plates have been manufactured by recording in photoresist the circular fringes transmitted by a Fabry-Perot interferometer. The fringe pattern is scanned through one order by an axial translation of one of the mirrors and a series of exposures is recorded in such a way that a triangular groove profile is generated. It has been demonstrated that it is possible to achieve efficiencies of the order of 70% for zone plates working in transmission and on axis. Unfortunately their numerical apertures are limited by the properties of the camera used to photograph the fringes and this limits the range of application of technique is capable of generating zone plates that might seriously be considered as alternatives to conventional lenses.
15 citations
TL;DR: In this article, the authors describe the use of a zone plate as the dispersing element in a monochromator in which the spectrum is scanned by means of a linear axial displacement.
Abstract: The authors describe the use of a zone plate as the dispersing element in a monochromator in which the spectrum is scanned by means of a linear axial displacement. It is considered for use as a wavelength-encoded linear displacement transducer and is shown to be both effective and simple to construct.
15 citations
TL;DR: Fresnel zone plates with minimum zone widths down to 50 nm were fabricated by electron-beam lithography, tested, and used in the scanning x-ray microscope at the Brookhaven National Synchrotron Light Source.
Abstract: Fresnel zone plates with minimum zone widths down to 50 nm were fabricated by electron‐beam lithography, tested, and used in the scanning x‐ray microscope at the Brookhaven National Synchrotron Light Source. The zone plates consist of gold rings on a silicon nitride window. Characterization of the zone plates included efficiency and resolution measurements in the first order focus. Spatial resolution down to 75 nm was measured. The best zone plates showed negligible astigmatism, and a first order efficiency in excess of 5% has been achieved. A new method for development monitoring during the fabrication procedure using an optical microscope with polarized light and crossed analyzer was introduced. For the inspection of the fabrication accuracy and, in particular, for ellipticity, a moire pattern technique was employed. Using these zone plates as objective lenses, x‐ray images of biological specimens were obtained with 70 nm resolution.
TL;DR: In this article, a common-path interferometer which uses zone plates as beam-splitting and imaging components is described, where a two-dimensional array of reflective zone plates is used to define a 3D array of positions.
Abstract: Interferometry gives a precise indication of the relative separation of two coherent sources If the sources are images produced by an optical system, their positions are controlled by the respective components of the system Interferometry can therefore be used to measure the relative positions, in three-dimensions, of the optical components This paper describes a common-path interferometer which uses zone plates as beam-splitting and imaging components A two-dimensional array of reflective zone plates is used to define a three-dimensional array of positions, ie an optical ‘space frame’ Particular examples of wavefront geometry are used to show how the sensitivity to displacement can be varied by controlling the relative shear of the wavefronts The device has applications in metrology, for example in checking the positioning performance of multi-axis measuring machines
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TL;DR: In this paper, the phase contribution obtained by the superposition of two tilted wavefronts, one cylindrical and the other plane, is considered and the effect of diffraction on the obtained holograms is calculated.
01 Jan 1988
TL;DR: Based on Kirchhoff's diffraction theory, the modulation transfer function MTF has been calculated as a criterion for the imaging quality of a micro zone plate as discussed by the authors, which is used for imaging with high magnification in x-ray microscopes.
Abstract: Based on Kirchhoff’s diffraction theory, the modulation transfer function MTF has been calculated as a criterion for the imaging quality of a micro zone plate. The micro zone plate will be used for imaging with high magnification in x-ray microscopes. The optical arrangement of an x-ray microscope is sketched in Fig.1 [1].
Patent•
19 Jan 1988
TL;DR: A Fresnel zone-plate reflector of a transmitting/receiving antenna contains a flat metal reflector and a plurality of concentrically arranged metal circular rings in a plane parallel to the reflector at a spacing of a quarter of a wavelength.
Abstract: A Fresnel zone-plate reflector of a transmitting/receiving antenna contains a flat metal reflector and a plurality of concentrically arranged metal circular rings in a plane parallel to the reflector and at a spacing of a quarter of a wavelength, such that the wave elements of a spherical wave front reflected on the circular rings are added in the correct phase to the wave elements reflected (in the ideal case) on the reflector surface, to form a flat wave front.
Patent•
17 Oct 1988
TL;DR: In this paper, an optical pickup with variable focal length is obtained by making the resultant focal length variable by means of a Fresnel zone plate using a liquid crystal panel, which is applied to the focus servo of the optical pickup.
Abstract: PURPOSE:To obtain an optical pickup, which is light in weight and to which application of any mechanical focus servo is not required, by making the resultant focal length of an optical system variable by means of a Fresnel zone plate using a liquid crystal panel CONSTITUTION:Laser light 11 emitted from a semiconductor laser 1 is focused on a disk base plate 7 after it is passed through a Fresnel zone plate using a transmission type liquid crystal panel 3 and optical lens 5 When this optical system is applied to the focus servo of the optical pickup, the focusing position is controlled by calculating a new focusing position by means of a CPU 15 in accordance with a detection signal of a focusing position shifting detecting circuit 13 and changing the resultant focal length by changing the spatial frequency of the Fresnel zone plate using the liquid crystal panel 3 by accessing a pattern generator 9 Therefore, an optical system which has no mechanically driven section and whose focal length is variable can be formed
TL;DR: In this paper, a prototype synchrotron radiation stepper for quarter-micron devices has been developed and installed at the Photon Factory in the National Laboratory for High Energy Physics, Japan.
Abstract: A prototype synchrotron radiation (SR) stepper for quarter‐micron devices has been developed and installed at the Photon Factory in the National Laboratory for High Energy Physics, Japan. The stepper features are, (i) exposure in an atmospheric environment, (ii) large exposure area (25‐mm sq), and (iii) alignment error detection at all times, including during exposure. The stepper consists of an SR extracting chamber, precision mechanical stages, and an alignment error detection system. An SR beam in UHV goes through a beryllium window into an atmospheric environment, and covers the 25‐mm sq exposure area by using an oscillating mirror. Patterns on a mask are imprinted onto a wafer. Mask and wafer are, respectively, held in place with vacuum chucks. Their subsequent positioning movements are driven in 6 degrees of freedom by piezoelectric actuators for fine alignment and gap setting. The alignment system, based on the previous Fresnel lens optical system, newly employs a differential mode linear Fresnel zone plate alignment method. As the optical system for this method is located at the outside of an SR beam, it can detect an alignment error between a mask and a wafer at all times, including during exposure. Patterns measuring 0.2 μm were completely successfully imprinted on a wafer. Until now, 0.03‐μm (3σ) positioning accuracy and 0.2‐μm (3σ) overlay accuracy were achieved.
TL;DR: In this paper, a composite zone plate was used to construct an optical pulse delay unit with a reduced number of components by using composite zone plates and its successful implementation with a dynamic range of 300 ps delay of 40 ps diode laser pulses.
Abstract: Optical pulse delay technique is important in such fields as time-resolved spectroscopy, optical sampling and very high speed time division multiplexing of digital data. This paper reports a proposal to assemble an optical pulse delay unit with a reduced number of components by using a composite zone plate and its successful implementation with a dynamic range of 300 ps delay of 40 ps diode laser pulses.
Patent•
15 Jun 1988
TL;DR: In this article, a flexible Fresnel zone plate was used to receive microwave signals, adapted to be wound on a cylindrical member similar to that used in a roller blind.
Abstract: Flat antennas such as Fresnel zone plates may be used to receive microwave signals. Such antennas are mounted on windows (4) and focus the signals on a horn feed (10). This invention discloses a flexible Fresnel zone plate (1) adapted to be wound on a cylindrical member (3) similar to that used in a roller blind. The antenna may thus be readily mounted against a window (4), and the Fresnel zone plate unwound to receive signals.
20 Aug 1988
TL;DR: In this article, a composite zone plate was used to construct an optical pulse delay unit with a reduced number of components by using composite zone plates and its successful implementation with a dynamic range of 300 ps delay of 40 ps diode laser pulses.
Abstract: Optical pulse delay technique is important in such fields as time-resolved spectroscopy, optical sampling and very high speed time division multiplexing of digital data. This paper reports a proposal to assemble an optical pulse delay unit with a reduced number of components by using a composite zone plate and its successful implementation with a dynamic range of 300 ps delay of 40 ps diode laser pulses.
01 Jan 1988
TL;DR: In this paper, the authors present a method for fabricating effective focusing X-ray elements with the structure of three-dimensional Fresnel zones, that is, Bragg Fresnel optics.
Abstract: Possibilities of control and focusing of X-rays have been discussed repeatedly since the discovery made by Rontgen. It turned out, however, that applications of the principles of optical element fabrication adopted in visible light, infrared radiation and other wavelength ranges are rather limited due to negligible difference of the refractive index from unity, a relatively large absorption coefficient and the necessity to fabricate optical elements with the accuracy compared to a radiation wavelength. In the last years the methods of X-ray optics acquire further extensive development because of the advances in microstructuring technology, namely, structure fabrication with element sizes up to one hundred angstroms, sputtering technology and that of the growth of thin films of different materials, and due to the advances in the investigation of X-ray diffraction. In our opinion, at present there exists a possibility to set and solve the task of fabricating effective focusing X-ray elements with the structure of three-dimensional Fresnel zones, that is, Bragg Fresnel optics. These elements can be made on the basis of multilayer interference mirrors for the nanometer wavelength range (0.5nm≲λ≲10nm) and semiconductor perfect crystals with heterostructures for the wavelength range of 0.1A≲λ≲5A. The principal peculiarity of Bragg-Fresnel X-ray elements lies in the fact that coherent Bragg scattering by separate layers is used in them. As it will be shown, this phenomenon permits increasing their diffraction efficiency, widening the spectrum range and angular aperture and gives a possibility to realize amplitude and phase modulations of radiation, to switch X-ray elements by an electrical signal, ultrasound and light signals.
Patent•
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16 Apr 1988
Abstract: PURPOSE:To permit formation of a large-diameter FZP by dividing diffraction rings to plural groups successively from the inner side and setting the positions of two light sources at the time of exposing in such a manner that the ring radii applying prescribed condensing characteristics at the use wavelengths of the representative diffraction rings and the radii of the interference ring is of the same sequence from the center at the time of exposing coincide with each other for each of the respective groups. CONSTITUTION:The Fresnel zone plate (FZP) patterns are divided to the diffraction ring groups on the inside L1, middle side L2, outside L3, etc. The representative rings are respectively selected with the respective groups. The ring radii are calculated from the conditions for using the FZP and the positions of the two light sources which give the same diffraction ring radii as the radii calculated with the diffraction rings of the same number at the time of exposing are counted back and determined. The interference pattern at the time of exposing and the diffraction ring pattern required at the time of use can be made identical with each other respectively at sufficient approximations for each of the respective groups, so that the FZP corrected in aberration is obtd. Since the aberrations are thereby removed in the prepn. of the FZP by a holographic exposing method, the formation of the larger-diameter FZP is permitted.
TL;DR: In this article, the authors show a step-by-step improvement of fabricated microzone plates with an outermost zone width of 50 nm, and a thin titanium intermediate layer is used as a stable mask to generate ion-milled gold absorber rings with very steep walls.
Abstract: Microzone plates have been fabricated with the aid of a 100- keV electron beam lithography system. The system has been designed for generating structures with lateral dimensions of less than 100 nm. The particular demands on high resolution, high efficiency imaging Fresnel zone plates and the resultant problems concerning lithography and pattern transfer are discussed. We show a step-by-step improvement of fabricated microzone plates with an outermost zone width of 50 nm. A thin titanium intermediate layer is used as a stable mask to generate ion-milled gold absorber rings with very steep walls. The zone plates have been tested by imaging one another in an x-ray microscope and ave been compared to the image obtained with the holographically fabricated MZP3 microzone plate from Gottingen.
TL;DR: An easy and accurate method to detect the kind of disarrangement and its magnitude in the adjustment process of a Mach-Zehnder interfermeter by means of an equilateral hyperbolic zone plate is explained in this paper.
Abstract: An easy and accurate method to detect the kind of disarrangement and its magnitude in the adjustment process of a Mach-Zehnder interfermeter by means of an equilateral hyperbolic zone plate is explained.
20 Jul 1988
01 Jan 1988
TL;DR: The resolution performance of a soft x-ray microscope which uses a zone plate as its focusing element is primarily dependent on the scale and accuracy with which the zone plate can be made as discussed by the authors.
Abstract: The resolution performance of a soft x-ray microscope which uses a zone plate as its focusing element is primarily dependent on the scale and accuracy with which the zone plate can be made. In order to be capable of attaining spatial resolution in the 10 – 100 nm region it is necessary to fabricate zone plates which have finest rings of this scale. Also the placement of the zones must be accurate to a fraction of the finest zone width across the zone plate diameter if aberrations are not to limit resolution.
01 Jan 1988
TL;DR: In this paper, the authors describe the fabrication and testing of sputtered-sliced linear zone plates, designed to focus 8 keV (λ = 1.54 A) x-ray photons from conventional Cu X-ray sources.
Abstract: We describe the fabrication and testing of sputtered-sliced linear zone plates, designed to focus 8 keV (λ = 1.54 A) x-ray photons from conventional Cu x-ray sources.
01 Jan 1988
TL;DR: The finest soft x-ray probes generated so far have been produced by modified fresnel zone plates [1,2,3] as discussed by the authors, which are used to demagnify a source of x rays.
Abstract: Image formation in scanning x-ray microscopy is achieved by rastering a semi transparent specimen across a small x-ray probe and counting the number of photons transmitted by the specimen at position of the scan. The finest soft x-ray probes generated so far have been produced by modified fresnel zone plates [1,2]. In scanning x-ray microscopy a zone plate is used to demagnify a source of x rays. The dimensions of the probe are primarily determined by the width of the finest zone (dr) of the zone plate. If the zone plate has been fabricated with sufficient accuracy and is illuminated with x-rays which are both spatially and temporally coherent then the probe shape will resemble an airy pattern which has a full width at half maximum (FWHM) which is very nearly equal to the finest zone.
01 Jan 1988
TL;DR: Fresnel zone plates which are used as imaging lenses for soft x-rays are required to have high resolution, high efficiency, and low distortions as discussed by the authors. But this means smallest possible widths of the outer zones, high aspect ratios of the absorber rings, and a positional accuracy of the structures to a fraction of the inner zone width.
Abstract: Fresnel zone plates which are used as imaging lenses for soft x-rays are required to have high resolution, high efficiency, and low distortions. In terms of practical realisation, this means smallest possible widths of the outer zones, high aspect ratios of the absorber rings, and a positional accuracy of the structures to a fraction of the outer zone width. Additionally, the absorptance of the membranes carrying the zone plate has to be minimized.
16 Jan 1988
TL;DR: In this article, a simple method for optical alignment and positioning between two planes by means of a Circular Zone Plate (CZP) is proposed, in which the first plane is determined by the zone plate and the other one is related to position of a reflecting surface situated in the forward space of the ZP.
Abstract: A simple method for optical alignment and positioning between two planes by means of a Circular Zone Plate (CZP), is proposed.The first plane is determinated by the zone plate and the other one is related to position of a reflecting surface situated in the forward space of the zone plate. Two points sources are generated by the same zone plate,when it is illuminated by a plane wave, and by several diffracted orders reflected by the reflecting surface.. Interference pattern produced by two spherical waves depend on the relative position of the generating sources. Tilting or axial misalignment between the planes determine the relative position of the two point sources and it yield fringe pattern variation.