Showing papers on "Zone plate published in 2002"
TL;DR: M maskless, single-step fabrication of strongly birefringent Fresnel zone plates by focusing of femtosecond laser pulses deep within silica substrates is demonstrated.
Abstract: We demonstrate maskless, single-step fabrication of strongly birefringent Fresnel zone plates by focusing of femtosecond laser pulses deep within silica substrates. The process allows us to produce alternate zone rings directly by inducing a local refractive-index modification of the order of n~10-2 . The embedded zone plates shown in this Letter exhibit efficiencies that vary by as much as a factor of ~6 for orthogonal polarizations. Focal lengths of primary and secondary foci are shown to compare well with theory.
162 citations
TL;DR: The Fresnel zone plate was fabricated by embedding voids in silica glass and investigated the focusing properties by launching a He-Ne laser beam into the zone plate and agreed with the theoretical value of 6.1 mum.
Abstract: We fabricated the Fresnel zone plate by embedding voids in silica glass. We investigated the focusing properties by launching a He-Ne laser beam into the zone plate. The spot size of the primary focal point was 7.0 mum and agreed with the theoretical value of 6.1 mum. The diffraction efficiency was 2.0 %. This technique enables us to make alignment free micro-scale lenses inside bulk materials.
120 citations
Patent•
29 May 2002
TL;DR: In this paper, the preferential imaging of the optical train is achieved using a chromatic lens in a suitably configured imaging system, which is an example of such a lens; its focal length is inversely proportional to the X-ray wavelength.
Abstract: An element-specific imaging technique utilizes the element-specific fluorescence X-rays that are induced by primary ionizing radiation. The fluorescence X-rays from an element of interest are then preferentially imaged onto a detector using an optical train. The preferential imaging of the optical train is achieved using a chromatic lens in a suitably configured imaging system. A zone plate is an example of such a chromatic lens; its focal length is inversely proportional to the X-ray wavelength. Enhancement of preferential imaging of a given element in the test sample can be obtained if the zone plate lens itself is made of a compound containing substantially the same element. For example, when imaging copper using the Cu La spectral line, a copper zone plate lens is used. This enhances the preferential imaging of the zone plate lens because its diffraction efficiency (percent of incident energy diffracted into the focus) changes rapidly near an absorption line and can be made to peak at the X-ray fluorescence line of the element from which it is fabricated. In another embodiment, a spectral filter, such as a multilayer optic or crystal, is used in the optical train to achieve preferential imaging in a fluorescence microscope employing either a chromatic or an achromatic lens.
97 citations
TL;DR: In this paper, a twin zone plate (TZP) setup was used to generate focal points closely spaced within the TZP spatial resolution of 160 nm for X-ray imaging in differential interference contrast (DIC).
Abstract: X-ray imaging in differential interference contrast (DIC) with submicrometer optical resolution was performed by using a twin zone plate (TZP) setup generating focal spots closely spaced within the TZP spatial resolution of 160 nm. Optical path differences introduced by the sample are recorded by a CCD camera in a standard full-field imaging and by an aperture photodiode in a standard scanning transmission x-ray microscope. Applying this x-ray DIC technique, we demonstrate for both the full-field imaging and scanning x-ray microscope methods a drastic increase in image contrast (approximately 20×) for a low-absorbing specimen, similar to the Nomarski DIC method for visible-light microscopy.
60 citations
Patent•
30 Sep 2002
TL;DR: In this article, a light emitting device and a manufacturing method thereof and a display used the light-emitting device, in which fine patterning for the light emitting devices is realized by a simple process and the light leakage is prevented and the efficiency at extracting light is increased.
Abstract: A light emitting device and a manufacturing method thereof and a display used the light emitting device, in which fine patterning for the light emitting device is realized by a simple process and the light leakage is prevented and the efficiency at extracting light is increased, are provided. The light emitting device provides an organic electroluminescent (EL) device in which electrodes and a luminescent layer are formed, a diffraction grating or a zone plate, and a filter. Light emitted from the luminescent layer transmits through the diffraction grating or the zone plate, which is formed with a designated grating pitch, or is reflected at the diffraction grating or the zone plate. With this, the transmitting or reflecting light is controlled to be in a designated angle region. And when the light is transmitted through the filter, light having different color tone and chromaticity from those of the light emitted from the luminescent layer is extracted.
59 citations
TL;DR: In this paper, an x-ray microtomography method combined with hard X-ray imaging microscopy was developed that has a potential spatial resolution of the order of 10-100 nm.
Abstract: An x-ray microtomography method combined with hard x-ray imaging microscopy was developed that has a potential spatial resolution of the order of 10–100 nm. The system consists of a high-brilliance undulator source of SPring-8, a beam diffuser plate to reduce the coherence of the illumination, a high-precision rotating sample stage, a Fresnel zone plate objective, and a high-resolution x-ray imaging detector. The three-dimensional images of several samples were observed and successfully reconstructed with a pitch pattern of 0.6 μm.
54 citations
Book•
31 Aug 2002
TL;DR: In this article, an overview of Fresnel Zone Antenna Antennas is presented, including offset Fresnel zone antennas, single printed flat reflector, and phase correcting zone plate.
Abstract: Acknowledgement. 1: Introduction. 2: Offset Fresnel Zoneplate. 3: Phase Correcting Zoneplates. 4: Zonal Reflectors. 5: Single Printed Flat Reflector. 6: Reflective Array Antenna. 7: Other Fresnel Zone Antennas. Bibliography. Index.
46 citations
Patent•
15 Feb 2002
TL;DR: In this article, a diffraction type optical pickup lens is formed with an aspheric surface that a luminous flux having a wavelength λ 1 is converged at a first predetermined position.
Abstract: In a diffraction type optical pickup lens, at least one surface of a convergent lens is formed with such an aspheric surface that a luminous flux having a wavelength λ 1 is converged at a first predetermined position. At least one surface of the convergent lens is formed with a zone plate having such a wavelength selectivity that a luminous flux having a wavelength λ 2 is converged at a second predetermined position whereas the luminous flux having a wavelength λ 1 is transmitted therethrough as it is. The convergent lens is transparent to the luminous fluxes having the wavelengths λ 1 and λ 2 .
45 citations
TL;DR: In this paper, a simple setup using a zone plate as objective and a back-illuminated CCD as detector yields at moderate magnifications of M≈60 a spatial resolution of δx < 0.8μm demonstrated with a sample of mica.
Abstract: We report on experiments using high-harmonic (HH) radiation for microscopy imaging at 13 nm wavelength. A simple setup using a zone plate as objective and a back-illuminated CCD as detector yields at moderate magnifications of M≈60 a spatial resolution of δx<0.8 μm demonstrated with a sample of mica. The HH radiation was monochromatized by means of a high-efficiency multilayer monochromator consisting of two Mo/Si-mirros.
42 citations
TL;DR: A full-wave approach to quantitative characterization of x-ray zone plate lenses is proposed, and the possibilities of second-order focus enhancement by optimization of the zone plate thickness, line-to-space ratio, and zone tilt are studied numerically.
Abstract: A full-wave approach to quantitative characterization of x-ray zone plate lenses is proposed. Distributed focusing efficiency η(z) of a multifocus optical element is defined as the energy flux through the Airy disk of a reference perfect lens with variable focal length z. Maxima of this function characterize diffraction efficiencies and spatial resolution of the zone plate foci. The parabolic wave equation is used to take into account diffraction effects inside the optical element. Rough and fuzzy interface models are introduced to describe realistic zone profiles. Numerical simulation reveals the limited capability of zone width reduction to improve the zone plate imaging performance. The possibilities of second-order focus enhancement by optimization of the zone plate thickness, line-to-space ratio, and zone tilt are studied numerically.
42 citations
TL;DR: A proposed generalization of the Fresnel zone concept is described in the context of femtosecond optics, and experimentally verified using terahertz time-domain spectroscopy.
Abstract: The concept of the Fresnel zone is central to many areas of imaging. In tomographic imaging, the transverse spatial resolution can be limited by the size of the first Fresnel zone, usually defined only for monochromatic radiation. With the increasing prevalence of broadband tomographic imaging systems, a generalization of this concept is required. Here, a proposed generalization is described in the context of femtosecond optics, and experimentally verified using terahertz time-domain spectroscopy. Based on this definition, a simple zone plate design is demonstrated.
Patent•
05 Nov 2002
TL;DR: In this article, a Fresnel zone plate and a refractive lens are combined to solve the high chromatic aberration problem of zone plates, allowing the use of short wavelength radiation in the 1-15 nm spectral range.
Abstract: A lithography apparatus having achromatic Fresnel objective (AFO) that combines a Fresnel zone plate and a refractive Fresnel lens. The zone plate provides high resolution for imaging and focusing, while the refractive lens takes advantage of the refraction index change properties of appropriate elements near absorption edges to recombine the electromagnetic radiation of different energies dispersed by the zone plate. This compound lens effectively solves the high chromatic aberration problem of zone plates. The lithography apparatus allows the use of short wavelength radiation in the 1-15 nm spectral range to print high resolution features as small as 20 nm.
TL;DR: A novel diffractive optical element that combines the functions of a grating and a zone plate is fabricated with Fourier optical techniques and employed here for the first time at EUV/soft-x-ray wavelengths, which results in the first direct measurement of the dispersive part of the refractive index.
Abstract: To the best of our knowledge, the first direct measurement of the dispersive part of the refractive index is performed at extreme-ultraviolet (EUV) wavelengths, where absorption is higher as compared with hard-x-ray and visible wavelengths. A novel diffractive optical element that combines the functions of a grating and a zone plate is fabricated with Fourier optical techniques and employed here for the first time at EUV/soft-x-ray wavelengths. Both the real and the imaginary parts of the complex refractive indices are measured directly by this technique without recourse to Kramers-Kronig transformations. Data for Al and Ni in the vicinity of their L and M edges, respectively, are presented as first examples of this technique.
TL;DR: A differential phase contrast, similar to Nomarski's differential interference contrast for the light microscope, is observed, which results in a tremendous increase in image contrast of up to 20 % when imaging low absorbing specimen.
Abstract: It is demonstrated that in a zone plate based scanning X-ray microscope, used to image low absorbing, heterogeneous matter at a mesoscopic scale, differential phase contrast (DPC) can be implemented without adding any additional optical component to the normal scheme of the microscope. The DPC mode is simply generated by an appropriate positioning and alignment of microscope apertures. Diffraction from the apertures produces a wave front with a non-uniform intensity. The signal recorded by a pinhole photo diode located in the intensity gradient is highly sensitive to phase changes introduced by the specimen to be recorded. The feasibility of this novel DPC technique was proven with the scanning X-ray microscope at the ID21 beamline of the European Synchrotron Radiation facility (ESRF) operated at 6 keV photon energy. We observe a differential phase contrast, similar to Nomarski’s differential interference contrast for the light microscope, which results in a tremendous increase in image contrast of up to 20 % when imaging low absorbing specimen.
TL;DR: In this paper, a rotating spiral zone plate was used to implement and measure the rotational Doppler effect for plane-polarized optical beams with helical wave front (optical vortices).
Abstract: A rotating spiral zone plate was used to implement and measure the rotational Doppler effect for plane-polarized optical beams with helical wave front (optical vortices). The frequency shift was analyzed in terms of energy exchange between the beams and moving optical elements.
TL;DR: It can be said from results that a spatial resolution better than 0.1 microm in the high-energy X-ray region is in prospect by the development of a multilayer FZP with a narrower outermost zone width in the near future.
Abstract: Hard X-ray microscopy with high spatial resolution (≤0.1 µm) using a high-energy and high-brilliance X-ray microprobe is expected to be a promising technology for various types of analysis, imaging etc. in materials science, biology and medicine. A multilayer Fresnel zone plate (FZP) could be a promising approach to focusing optics in the high-energy X-ray region (≥20 keV) because a large thickness (aspect ratio) can be available. Various types of multilayer FZPs have been fabricated by DC sputtering deposition. Their focusing characteristics have been evaluated at the high-brilliance undulator beamline BL47XU of SPring-8. An optical system using a Cu/Al multilayer FZP (with an outermost zone width of 0.25 µm) as the focusing optics fabricated by the optimum deposition condition with precise film (zone) thickness control has attained an almost diffraction-limited microbeam of 0.3–0.35 µm at 8.9 keV. A line-and-space resolution test pattern has been observed: fine structures up to 0.2 µm were clearly observed in the measured image. This FZP has been working since 1995, keeping good focusing characteristics. It can be said from these results that a spatial resolution better than 0.1 µm in the high-energy X-ray region is in prospect by the development of a multilayer FZP with a narrower outermost zone width in the near future.
20 Sep 2002
TL;DR: In this article, the zone plates are aligned laterally to within better than an outermost zone width and longitudinally within the optical near-field, and they form a single optical element of larger effective thickness and improved efficiency and reduced background from undiffracted radiation.
Abstract: We use Fresnel zone plates as focusing optics in hard x-ray microprobes at energies typically between 6 and 30 keV While a spatial resolution close to 01 {micro}m can currently be achieved, highest spatial resolution is obtained only at reduced diffraction efficiency due to manufacturing limitations with respect to the aspect ratios of zone plates To increase the effective thickness of zone plates, we are stacking several identical zone plates on-axis in close proximity If the zone plates are aligned laterally to within better than an outermost zone width and longitudinally within the optical near-field, they form a single optical element of larger effective thickness and improved efficiency and reduced background from undiffracted radiation This allows us both to use zone plates of moderate outermost zone width at energies of 30 keV and above, as well as to increase the efficiency of zone plates with small outermost zone widths particularly for the energy range of 6-15 keV
TL;DR: In this paper, a linear-transmission Fresnel-zone-plate lens is used for coupling a monochromatic X-ray beam of 13.2 V into a planar waveguide.
Abstract: A linear-transmission Fresnel-zone-plate lens is used for coupling a monochromatic X-ray beam of 13.2 keV into a planar X-ray waveguide. The zone plate focuses the beam parallel to the entrance of the waveguide, by which means a flux enhancement of a factor of 54 inside the waveguide is obtained. This substantially enlarges the range of X-ray diffraction experiments that can be performed on samples confined within the waveguide. The coherent properties of the beam, as obtained at a third-generation synchrotron facility, are investigated by comparing the experimental data with numerical calculations in which partial coherence is taken into account by propagation of the mutual intensity function. The conditions for which the X-rays travelling through the waveguide are coherent are discussed.
TL;DR: In this article, a Zernike-type phase-contrast X-ray microscope with a zone plate and a phase plate was constructed at the Photon Factory BL3C2.
Abstract: A Zernike-type phase-contrast X-ray microscope with a zone plate and a phase plate was constructed at the Photon Factory BL3C2. Parallel monochromatic X-rays of 8.97 keV were incident on a specimen and a direct beam transmitted through the specimen was focused on the back focal plane of the zone plate, where an aluminium phase plate was placed. Tantalum line patterns as fine as 0.3 µm could be imaged. Phase-contrast images of polypropylene wires and polystyrene latex beads were obtained, which showed better contrast than that of their bright field images.
Patent•
20 May 2002
TL;DR: In this article, a system for inspecting lithography masks utilizing a laser source to produce a coherent electromagnetic radiation pulse is presented, where the pulse is passed to a target which creates a plasma resulting in an extreme ultraviolet (EUV) beam.
Abstract: A system for inspecting lithography masks utilizing a laser source to produce a coherent electromagnetic radiation pulse. The pulse is passed to a target which creates a plasma resulting in an extreme ultraviolet (EUV) beam. The beam is condensed and passed through an aperture to define a cross-sectional area of the condensed EUV beam on a lithography mask. A transmission zone plate resolves the image reflected from the lithography mask and passes the image to a detector for analysis.
TL;DR: In this paper, an example of a 1 mm diameter wide zone plate, optimized for a 23 keV X-ray beam, showing an aspect ratio of the outermost zone of up to 10.
01 Nov 2002
TL;DR: Circular and linear zone plates have been fabricated on the surface of silicon crystals for the energy of 8 keV by electron beam lithography and deep ion plasma etching methods and the experimental testing of the zone plates has been conducted on SPring-8 and ESRF synchrotron radiation sources.
Abstract: Circular and linear zone plates have been fabricated on the surface of silicon crystals for the energy of 8 keV by electron beam lithography and deep ion plasma etching methods. Various variants of compound zone plates with first, second, third diffraction orders have been made. The zone relief height is about 10 mkm, the outermost zone width of the zone plate is 0.4 mkm. The experimental testing of the zone plates has been conducted on SPring-8 and ESRF synchrotron radiation sources. A focused spot size and diffraction efficiency measured by knife-edge scanning are accordingly 0.5 mkm and 39% for the first order circular zone plate.
Patent•
25 Apr 2002
TL;DR: An achromatic Fresnel optic that combines a Fresnel zone plate and a refractive Fresnel lens is proposed in this article, where the zone plate provides high resolution for imaging and focusing, while the refractive lens takes advantage of the refraction index change properties of appropriate elements near absorption edges to recombine the electromagnetic radiation of different energies dispersed by the zone plates.
Abstract: An achromatic Fresnel optic that combines a Fresnel zone plate and a refractive Fresnel lens. The zone plate provides high resolution for imaging and focusing, while the refractive lens takes advantage of the refraction index change properties of appropriate elements near absorption edges to recombine the electromagnetic radiation of different energies dispersed by the zone plate. This compound lens effectively solves the high chromatic aberration problem of zone plates. The AFO has a wide range of potential applications in lithography, microimaging with various contrast mechanisms and measurement techniques.
TL;DR: The feasibility of phase-contrast microscopy for observing transparent samples was successfully demonstrated by imaging small polystyrene particles by placing a phase plate made of gold in the back focal plane of the zone plate.
Abstract: An imaging transmission hard X-ray microscope has been constructed at beamline BL24XU of SPring-8. It makes use of a phase zone plate made of tantalum with a diameter of 1 mm and an outer-most zone width of 50 nm, aiming at a wide field of view and a high spatial resolution. The performance test was carried out at a photon energy of 10 keV. A field of view as wide as ∼200 µm in diameter was achieved. The spatial resolution was measured to be 220 nm by analyzing a knife-edge image. Further, a line-and-space pattern as fine as 100 nm could be imaged. By placing a phase plate made of gold in the back focal plane of the zone plate, phase-contrast microscopy using Zernike's method was also carried out. The feasibility of phase-contrast microscopy for observing transparent samples was successfully demonstrated by imaging small polystyrene particles.
TL;DR: In this article, the use of a Fresnel zone plate to characterize interference fringes was proposed to achieve high precision measurement of fringe characteristics for a wide range of fringe periods with properly controlled errors.
Abstract: In scanning beam interference lithography, a resist-coated substrate is scanned under phase-locked interfering beams to pattern large gratings or grids with nanometer level distortions. To achieve design goals, it is required to measure the spatial period, phase, and rotation of the interference fringes in real-time with high precision. In this article, we report the use of a Fresnel zone plate to characterize interference fringes. With properly controlled errors, it should enable us to achieve high precision measurement of fringe characteristics for a wide range of fringe periods. The mathematical model, details of the metrological procedure, and experimental results are presented.
TL;DR: In this article, the performance of a Fresnel zone plate has been tested by observing the focusing property of higher-order diffraction, and the zone material was made from 1'µm-thick tantalum and the outermost zone width was 0.25'
Abstract: The performance of a Fresnel zone plate has been tested by observing the focusing property of higher-order diffraction. The Fresnel zone plate was fabricated by the electron-beam lithography technique. The zone material was made from 1 µm-thick tantalum and the outermost zone width was 0.25 µm. The third-order focused spot size measured by the knife-edge scan method was 0.1 µm full width at half-maximum at an X-ray energy of 8 keV, which is exactly equal to one-third of the first-order focal spot size.
TL;DR: A Zernike-type imaging microscope using a sputtered-sliced Fresnel zone plate (SS-FZP) has been developed and tested at an X-ray energy of 25 keV and different image contrast was observed compared with the bright-field image contrast.
Abstract: A Zernike-type imaging microscope using a sputtered-sliced Fresnel zone plate (SS-FZP) has been developed and tested at an X-ray energy of 25 keV. The SS-FZP was used as an objective. A copper (Cu) phase plate was placed at the back focal plane of the SS-FZP in order to produce phase contrast. The performance of the Zernike-type imaging microscope was tested with a gold (Au) mesh and a resolution test pattern at undulator beamline 47 of SPring-8. The Au mesh and the resolution test pattern could be imaged in transmission with a magnification of ×10.2. Owing to the Cu phase plate, different image contrast was observed compared with the bright-field image contrast. Tantalum microstructures down to 0.5 µm line-and-space have been observed on spatial resolution test patterns.
01 Nov 2002
TL;DR: An off-axis zone-plate monochromator for diffraction-imaging experiments at beam line 901 at the Advanced Light Source (ALS) synchrotron-radiation facility at Berkeley USA is described in this paper.
Abstract: We report the design and construction of an off-axis zone-plate monochromator for diffraction-imaging experiments at beam line 901 at the Advanced Light Source (ALS) synchrotron-radiation facility at Berkeley USA The device is based on an off-axis zone plate which can be conveniently inserted into or retracted from the beam We discuss design issues such as the efficiency and spectral purity of the system and the technique for designing heat-tolerant windows for soft x-ray undulator beams The monochromator functions successfully and good-quality diffractions patterns are being made with the beam it delivers
13 Aug 2002
TL;DR: In this article, a phase shifting Fresnel Zone Plate (FZP) was fabricated for hard x-rays and an aspect ratio of 11 has been achieved for 110 nm outermost zone width.
Abstract: Soft x-ray lithography technology has been applied to fabrication of phase shifting Fresnel Zone Plate (FZP's) for hard x-rays. Effects of the exposure conditions, developing system, and electroplating process parameters on line width and aspect ratio have been analyzed. The process has been optimized and an aspect ratio of 11 has been achieved for 110 nm outermost zone width. SEM and AFM have been used for preliminary metrology of the FZPs. The FZP optical performance was characterized at 8 keV photon energy at the 2-ID-D beam line at the Advanced Photon Source. Focusing efficiencies of 23% for FZPs apertures to 100 microns and 18% for 150-micron-diameter apertures have been obtained. The parameters of the fabricated FZP are in good agreement with the predicted values.
TL;DR: As an application of the microbeam technique, a two-dimensional distribution of constituent elements in forensic samples has been obtained (e.g. section view of human and elephant hairs) using fluorescent scanning microscopy.
Abstract: Hard X-ray microbeam experiments with sputtered-sliced Fresnel zone plates have been performed. Zone plates with an outermost zone width of 0.25 µm (#FZP1) and 0.1 µm (#FZP2) were fabricated and evaluated. In a scanning X-ray microscopy experiment, a line-and-space pattern with structure as fine as 0.1 µm was resolved using #FZP2 at an X-ray wavelength of 1 A. As an application of the microbeam technique, a two-dimensional distribution of constituent elements in forensic samples has been obtained (e.g. section view of human and elephant hairs) using fluorescent scanning microscopy.