Showing papers on "Zone plate published in 2010"

Planar plasmonic focusing and optical transport using CdS nanoribbon.

Abstract: Planar plasmonic focusing of surface plasmon polaritons (SPPs) by an in-plane nanostructure consisting of Ag-column arrays and an in-plane Fresnel zone plate (FZP) with a Cu grating underneath for energy compensation was demonstrated. The CdS-based hybrid plasmonic waveguide generated in the Ag-column arrays was characterized with a scanning near-field optical microscope. By using the FZP focusing structure, the SPP modes were separated from the CdS photoluminescence background and focused at the FZP focus area, and in this way, were used as the source for the SPP waveguide. Finite-difference time-domain simulations correspond with the experimental observations, suggesting that this is indeed an effective approach to control SPP coupling within the dielectric nanoribbon waveguide.

Sub-70 nm resolution tabletop microscopy at 13.8 nm using a compact laser–plasma EUV source

Abstract: We report the first (to our knowledge) demonstration of a tabletop, extreme UV (EUV) transmission microscope at 13.8nm wavelength with a spatial (half-pitch) resolution of 69nm. In the experiment, a compact laser–plasma EUV source based on a gas puff target is applied to illuminate an object. A multilayer ellipsoidal mirror is used to focus quasi-monochromatic EUV radiation onto the object, while a Fresnel zone plate objective forms the image. The experiment and the spatial resolution measurements, based on a knife-edge test, are described. The results might be useful for the realization of a compact high-resolution tabletop imaging systems for actinic defect characterization.

Analysis of spectrum distribution and optical losses under Fresnel lenses

Abstract: During late 1970s and early 1980s, Fresnel lenses have received more attention in the field of solar energy application. This paper briefly examines the Fresnel lens development since 1970s and investigates the losses inherent in the linear Fresnel lenses. The research develops the formulation that helps to quantify the linear lens’ transmittance loss and prism-tip scattering loss and then derive a realistic model to simulate the measured data. In addition, the research has identified an elliptical-based lens that comes closest to the condition of minimum deviation. Such lens closely duplicates the curvature needed for maximum transmission. The researcher applies different design wavelengths to study the contribution of each wavelength interval on the receiving plane.

Multifractal zone plates.

Abstract: We present multifractal zone plates (MFZPs) as what is to our knowledge a new family of diffractive lenses whose structure is based on the combination of fractal zone plates (FZPs) of different orders. The typical result is a composite of two FZPs with the central one having a first-order focal length f surrounded by outer zones with a third-order focal length f. The focusing properties of different members of this family are examined and compared with conventional composite Fresnel zone plates. It is shown that MFZPs improve the axial resolution and also give better performance under polychromatic illumination.

Feasibility study of hard-x-ray nanofocusing above 20 keV using compound photon sieves

Abstract: Combining the advantages of photon sieves (PSs) and compound Fresnel zone plates (CZPs), we designed compound photon sieves (CPSs) for hard-x-ray nanofocusing. A CPS consists of an inner PS using the first-order diffraction surrounded by an outer zone plate using the third-order diffraction. A robust digital prolate spheroidal window was used as an apodization window for the inner PS, making CPSs more flexible than CZPs. CPSs can provide not only slightly better resolution compared to CZPs, but also it can significantly suppress the sidelobes, leading to a high signal-to-noise ratio. Further improvement of the high-aspect-ratio metal nanostructure process will allow CPSs to be a promising candidate for hard-x-ray nanofocusing in the high-energy region above 20keV.

Focusing properties of Fresnel zone plates with spiral phase

Abstract: Focusing properties of Fresnel zone plates with spiral phase with integer and fractional topological charges illuminated by plane wave are studied. Numerical results show that hollow beams can be generated and can also be controlled by the number of the zones and the topological charge, which implies the potential applications of such kind of zone plate in trapping and manipulating particles.

Compound X-ray lens having multiple aligned zone plates

Abstract: A compound zone plate comprising a first zone plate frame including a first zone plate, a second zone plate frame including a second zone plate, and a base frame to which the first zone plate frame and the second zone plate frame are bonded. In examples, two more zone plates are added to make a four element optic. In the assembly process, the microbeads are used to ensure the parallelism, dial in the distance precisely between the zone plates by selecting the microbead size, possibly in response to the width of the frames, and ensure low friction lateral movement enabling nanometer precision alignment of the zone plates with respect to each other prior to being fixed by the adhesive. That is, when the frames are pressed together to ensure parallelism, it is still possible to align them to each other since the microbead layer facilitates the inplane movement of the alignment process.

Sub-15 nm Hard X-Ray Focusing with a New Total-Reflection Zone Plate

Abstract: A new total-reflection zone plate that consists of a reflective zone pattern with varied-space on a flat substrate was fabricated for hard X-ray nanofocusing. This device is much easier to fabricate than other focusing devices. This is because its focusing size is much smaller than its finest constituent structure since it exploits the effect of glancing X-rays by having a small total reflection angle. Its focusing properties were evaluated using 10-keV X-rays and a focusing size of 14.4 nm was achieved.

Square Fresnel zone plate with spiral phase for generating zero axial irradiance

Abstract: A type of square Fresnel zone plate with spiral phase for generating zero axial irradiance is proposed. Diffraction patterns of the zone plates with different generalized topological charges are given by numerical simulation, which also suggests their potential applications in generating hollow beams.

Fabrication of multilayer Laue lenses by a combination of pulsed laser deposition and focused ion beam

Abstract: X-ray diffractive techniques using Fresnel zone plate lenses of various forms are of great technical interest because of their ability to form images at very high spatial resolution, but the zone plates are unfortunately very hard to produce by lithography. Alternatively, multilayer Laue lenses (MLLs) and multilayer zone plates are used due to the higher and easily adjustable aspect ratio necessary for different wavelengths. In this paper, the fabrication of a MLL by a combination of pulsed laser deposition and focused ion beam machining is described. All steps of the production of a Ti/ZrO(2) microlens test structure with focal length of 220 microm (for a wavelength of 2.88 nm in the "water window" regime) are explained in detail. It is shown that this combination of two powerful techniques is very effective for the fabrication of MLL. All steps can be done in a very precise and controlled way without introducing damage to the grown multilayer structures.

Thin microwave phase-shifting surface lens antenna made of square elements

Abstract: A 90° phase-correcting Fresnel zone plate (FZP) antenna has been realised at 30°GHz using a thin three-layer microwave phase-shifting surface (PSS) with square conducting shapes as the unit cell elements. These square elements allow dual-polarisation or circular-polarisation capabilities, which could not be achieved by the previously reported PSS structures the unit cell elements of which were strip-based. This new PSS lens was compared with the previously reported strip-element version. The square element PSS lens has slightly higher gain, but a small degradation to cross-polarisation level and gain bandwidth. The effect of altering the roll angle of the lens with the feed kept fixed was also investigated. This revealed that gain bandwidth is unchanged, but there is a marginal gain degradation and increase in the cross-polarisation level (albeit still well within an acceptable range) for certain roll angles.

High efficiency multilevel phase-type Fresnel zone plates produced by two-photon polymerization of SU-8

Abstract: In this paper, we report on high quality two-level phase-type Fresnel zone plates (FZPs) produced by femtosecond laser two-photon polymerization of the resin SU-8. The optical focusing property was tested using a simple experimental setup. Moreover, the lens imaging functions 'JLU' and '' (English and Chinese abbreviations for Jilin University) were also demonstrated. In order to further enhance the diffraction efficiency, four-level and eight-level FZPs were designed using theoretical calculation and rapidly realized by point-to-point femtosecond laser scanning. In this way, the diffractive efficiency was enhanced from 35.8% for the two-level phase lens to 67% for the four-level phase lens and 73.9% for the eight-level phase lens, which are the largest values reported so far.

Fabrication and Performance Test of Fresnel Zone Plate with 35 nm Outermost Zone Width in Hard X-Ray Region

Abstract: A Fresnel zone plate (FZP) with 35 nm outermost zone width has been fabricated and tested in the hard X-ray region. The FZP was made by electron beam lithography and reactive ion etching technique. The performance test of the FZP was carried out by measuring the focused beam profile for coherent hard X-ray beam at the beamline 20XU of SPring-8. The full width at half maximum of the focused beam profile measured by knife-edge scan method is 34.9±2.7 nm, that agrees well with the theoretical value of diffraction-limited resolution. Applications to scanning microscopy were also carried out.

Modeling of kinematic diffraction from a thin silicon film illuminated by a coherent, focused X‐ray nanobeam

Abstract: A rigorous model of a diffraction experiment utilizing a coherent, monochromatic, X-ray beam, focused by a Fresnel zone plate onto a thin, perfect, single-crystal layer is presented In this model, first the coherent wave emanating from an ideal zone plate equipped with a direct-beam stop and order-sorting aperture is computed Then, diffraction of the focused wavefront by a thin silicon film positioned at the primary focal spot is calculated This diffracted wavefront is propagated to the detector position, and the intensity distribution at the detector plane is extracted The predictions of this model agree quite well with experimental data measured at the Center for Nanoscale Materials nanoprobe instrument at Sector 26 of the Advanced Photon Source

X-ray Phase Imaging Microscopy using a Fresnel Zone Plate and a Transmission Grating

Abstract: We report on a hard X‐ray phase imaging microscopy (a phase‐difference microscopy) that consists of an objective and a transmission grating. The simple optical system provides a quantitative phase image, and does not need a wave field mostly coherent on the objective. Our method has a spatial resolution almost same as that of the absorption contrast microscope image obtained by removing the grating. We demonstrate how our approach provides a phase image from experimentally obtained images. Our approach is attractive for easily appending a quantitative phase‐sensitive mode to normal X‐ray microscopes, and has potentially broad applications in biology and material sciences.

Zone-plate focusing of Bose–Einstein condensates for atom optics and erasable high-speed lithography of quantum electronic components

Abstract: We show that Fresnel zone plates (ZPs), fabricated in a solid surface, can sharply focus atomic Bose?Einstein condensates that quantum reflect from the surface or pass through the etched holes. The focusing process compresses the condensate by orders of magnitude despite inter-atomic repulsion. Crucially, the focusing dynamics are insensitive to quantum fluctuations of the atom cloud and largely preserve the condensates' coherence, suggesting applications in passive atom-optical elements, for example ZP lenses that focus atomic matter waves and light at the same point to strengthen their interaction. We explore transmission ZP focusing of alkali atoms as a route to erasable and scalable lithography of quantum electronic components in two-dimensional electron gases (2DEGs) embedded in semiconductor nanostructures. To do this, we calculate the density profile of a 2DEG immediately below a patch of alkali atoms deposited on the surface of the nanostructure by zone-plate focusing. Our results reveal that surface-induced polarization of only a few thousand adsorbed atoms can locally deplete the electron gas. We show that, as a result, the focused deposition of alkali atoms by existing ZPs can create quantum electronic components on the 50?nm scale, comparable to that attainable by ion beam implantation but with minimal damage to either the nanostructure or electron gas.

New Developments in Femtosecond Soft X‐ray Spectroscopy

Abstract: Recent instrumentation developments in X‐ray spectroscopy for ultra‐fast time‐resolved measurements with soft X‐rays done in HZB Berlin during the last years are described. The significant performance improvements achieved this way are based on Fresnel diffraction from structures being fabricated on a surface of a total externally reflecting mirror. The first type of this spectrometer, an off‐axis reflection zone plate, has been implemented at the BESSY Femtoslicing setup and shows on the order of 20 times higher flux in the focal plane compared to the classical grating monochromator beamline. It has proven to serve very precise experiments with a time resolution down to 100 fs on magnetic materials after optical laser pulse excitation.

Lighting system and fresnel lens

Abstract: PROBLEM TO BE SOLVED: To provide a lighting system in which the light emitted to the side direction from a light source is utilized effectively, and most of light entered into an incident surface of a reflective system Fresnel lens is made to enter into a reflecting surface so as to utilize the light effectively. SOLUTION: The Fresnel lens 30 of a lighting system 1 has a refracted type Fresnel lens portion 41 and a reflected type Fresnel lens portion 51. The positions of second valley lines 57 of the reflected type Fresnel lens 51, in a direction along the optical axis Ax, are separated from the light source 20 or are mutually aligned, as the second valley lines 57 are arranged toward the outside. The distance in the direction along the optical axis from a second ridge line 56 to the second valley line 57 at the adjoining outside of the reflected type Fresnel lens 51 becomes larger as the second ridge line 56 is arranged farther outside. The reflecting surface 52 and the incident surface 53 at the outermost of the reflection-type Fresnel lens 51 surround the light source 20 along the circumference direction around the optical axis Ax. COPYRIGHT: (C)2011,JPO&INPIT

Compound Diffractive Lens Consisting of Fresnel Zone Plate and Frequency Selective Screen

Abstract: We describe a new Fresnel zone plate (FZP) and frequency selective screen (FSS) compound lens consisting of a binary FZP and FSS. The FZP has eight circular zones totally, four open and four closed, and the FSS is a square array of 40 × 40 four-leg loaded elements cut in a thin metal sheet. The FZP-FSS lens is designed for a paraxial plane-wave illumination at the frequency of 12 GHz, with a focal length of 15 cm. The compound lens is simulated and analyzed numerically by means of a specially developed hybrid PSTD-FDTD algorithm and software. The PSTD-FDTD results are contrasted with those obtained by lens prototype measurements. As a result, some attractive focusing and spectral properties of the FZP-FSS lens compared to the same-size FZP lens have been found: a frequency filtering property enhancement, about 2 dB increase in the peak focusing intensity, and more than 4 dB reduction of the first off-axis maximum. Both lenses have roughly the same transverse angular resolution.

Nanometer-scale ablation using focused, coherent extreme ultraviolet/soft x-ray light

Abstract: Ablation of holes having diameters as small as 82 nm and having clean walls was obtained in a poly(methyl methacrylate) on a silicon substrate by focusing pulses from a Ne-like Ar, 46.9 nm wavelength, capillary-discharge laser using a freestanding Fresnel zone plate diffracting into third order is described. Spectroscopic analysis of light from the ablation has also been performed. These results demonstrate the use of focused coherent EUV/SXR light for the direct nanoscale patterning of materials.

Fresnel led lens and led assembly thereof

Abstract: A Fresnel light emitting diode (LED) Lens and a LED Assembly thereof are provided. The Fresnel LED Lens is a lens disposed with a plurality of Fresnel optical surfaces. Each Fresnel optical surface includes a zone area having a plurality of drafts with vertical shape. Each Fresnel optical surface is arranged linearly along a center of a corresponding LED, and each Fresnel optical surface can used to focus light emitted from a LED chip so as to generate a quasi-circle distribution pattern of light with uniform light intensity and satisfy special optical requirements. A LED assembled formed by the Fresnel LED lens and a corresponding LED is used as a light source applied to illumination, mobile phone flashlights or camera flashlights.

Magnetic Imaging with X-rays

Abstract: Looking into a magnetic system with X-rays and revealing its secrets by imaging fuels a powerful and beautiful area of research. Magnetic imaging with X-rays allows us to understand and engineer the magnetic properties of thin films, heterostructures, and nanoscale magnets. In this chapter, the underlying concepts of imaging magnetic systems with X-rays are presented, and different microscope techniques are described.

Self-focused acoustic ejectors for viscous liquids

Abstract: Self-focused acoustic ejectors using the Fresnel zone plate (FZP) have been developed for ejecting viscous liquids, without nozzle, in the drop-on-demand mode. The FZP is composed of a lead zirconate titanate piezoelectric plate patterned with a series of annular electrodes, with the unelectroded region of the plate removed. Our results show that the acoustic waves are effectively self-focused by constructive interference in glycerin (with a viscosity of 1400 mPa s), giving small focal points with a high pressure. Due to the high attenuation, the wave pressure decreases significantly with the distance from the FZP. Nevertheless, the pressure at the focal points 2.5 and 6.5 mm from the FZP is high enough to eject glycerin droplets in the drop-on-demand mode. Driven by a simple wave train comprising a series of sinusoidal voltages with an amplitude of 35 V, a frequency of 4.28 MHz, and a duration of 2 ms, the ejector can eject fine glycerin droplets with a diameter of 0.4 mm at a repetition frequency of 120...

Simulation of heat transfer in zone plate optics irradiated by X-ray free electron laser radiation

Abstract: Zone plates are high quality optics that have the potential to provide diffraction-limited nano-focusing of hard X-ray free electron laser radiation. The present publication investigates theoretically the temperature behavior of metal zone plates on a diamond substrate irradiated by 0.1 nm X-rays from the European X-ray Free Electron Laser. The heat transfer in the optic is simulated by solving the transient heat equation with the finite element method. Two different zone plate designs are considered, one small zone plate placed in the direct beam and one larger zone plate after the monochromator. The main result is that for all investigated cases the maximum temperature in the metal zone plate layer is at least a factor 2 below the melting point of the respective material, proving the efficiency of the proposed cooling scheme. However, zone plates in the direct beam experience large and rapid temperature fluctuations of several hundred Kelvin that might prove fatal to the optic. The situation is different for optics behind the monochromator with fluctuations in the 20 K range and maximum temperatures well below room temperature. The simulation results give valuable indications on the temperature behavior to be expected and are a basis for future experimental heat transfer and mechanical stability investigations of fabricated nanostructures.

A new Scanning Transmission X‐ray Microscope at the ALS for operation up to 2500eV

Abstract: We report on the design and construction of a higher energy Scanning Transmission X‐ray Microscope on a new bend magnet beam line at the Advanced Light Source. Previously we have operated such an instrument on a bend magnet for C, N and O 1s NEXAFS spectroscopy. The new instrument will have similar performance at higher energies up to and including the S 1s edge at 2472eV. A new microscope configuration is planned. A more open geometry will allow a fluorescence detector to count emitted photons from the front surface of the sample. There will be a capability for zone plate scanning in addition to the more conventional sample scanning mode. This will add the capability for imaging a massive sample at high resolution over a limited field of view, so that heavy reaction cells may be used to study processes in‐situ, exploiting the longer photon attenuation length and the longer zone plate working distances available at higher photon energy. The energy range will extend down to include the C1s edge at 300eV, to allow high energy NEXAFS microscopic studies to correlate with the imaging of organics in the same sample region of interest.

Development of a Total Reflection Zone Plate for Hard X-ray Focusing

Abstract: A total reflection zone plate (TRZP) was developed and fabricated as a hard X-ray focusing device. It consists of a Au zone pattern drawn on a flat SiO2 substrate. The reflection only from the zone pattern can be extracted by operating the TRZP with a grazing incident angle between critical angles of Au and SiO2. The effective zone size is fully reduced to the drawn zone size with a small reduction ratio below 1/100. A focusing test using 10 keV X-rays was performed at the "Hyogo-ID" beamline (BL24XU) of SPring-8, and a focusing beam with diffraction-limited size was achieved.

Polarization‐independent and electrically tunable liquid‐crystal Fresnel lenses based on photoalignment in dye‐doped liquid crystals

Abstract: — This work demonstrates polarization-independent and electrically tunable liquid-crystal (LC) Fresnel lenses based on photoalignment in dye-doped liquid crystals (DDLCs). The LC alignments in the adjacent odd and even zones of the LC Fresnel lens are orthogonally hybrid alignments. Those are generated by surface treatment of homeotropic and homogeneous alignment layers, and the dye-adsorption layer onto the UV-cured surface-relief Fresnel zone plate. The maximum focusing efficiency (∼34.14%) of the fabricated LC Fresnel lens by applying a suitable AC voltage is close to the maximal theoretical focusing efficiency of a binary phase LC Fresnel lens (∼40.5%). Additionally, the focusing efficiency is polarization-independent and electrically tunable.