Diffractive Techniques Research Articles

Status of the Nanoscopium Scanning Hard X-ray Nanoprobe Beamline of Synchrotron Soleil

The Nanoscopium 155 m-long scanning hard X-ray nanoprobe beamline of Synchrotron Soleil (St Aubin, France) is dedicated to quantitative multi-modal 2D/3D imaging. The beamline aims to reach down to 30 nm spatial resolution in the 5–20 keV energy range. Two experimental stations working in consecutive operation mode will be dedicated to coherent diffractive imaging and scanning X-ray nanoprobe techniques. The beamline is in the construction phase, the first user experiments are expected in 2014. The main characteristics of the beamline and an overview of its status are given in this paper.

Whole-cell phase contrast imaging at the nanoscale using Fresnel Coherent Diffractive Imaging Tomography

X-ray tomography can provide structural information of whole cells in close to their native state. Radiation-induced damage, however, imposes a practical limit to image resolution, and as such, a choice between damage, image contrast, and image resolution must be made. New coherent diffractive imaging techniques, such Fresnel Coherent Diffractive Imaging (FCDI), allows quantitative phase information with exceptional dose efficiency, high contrast, and nano-scale resolution. Here we present three-dimensional quantitative images of a whole eukaryotic cell by FCDI at a spatial resolution below 70 nm with sufficient phase contrast to distinguish major cellular components. From our data, we estimate that the minimum dose required for a similar resolution is close to that predicted by the Rose criterion, considerably below accepted estimates of the maximum dose a frozen-hydrated cell can tolerate. Based on the dose efficiency, contrast, and resolution achieved, we expect this technique will find immediate applications in tomographic cellular characterisation.

Synthesis and fading of eighteenth-century Prussian blue pigments: a combined study by spectroscopic and diffractive techniques using laboratory and synchrotron radiation sources

Prussian blue, a hydrated iron(III) hexacyanoferrate(II) complex, is a synthetic pigment discovered in Berlin in 1704. Because of both its highly intense color and its low cost, Prussian blue was widely used as a pigment in paintings until the 1970s. The early preparative methods were rapidly recognized as a contributory factor in the fading of the pigment, a fading already known by the mid-eighteenth century. Herein two typical eighteenth-century empirical recipes have been reproduced and the resulting pigment analyzed to better understand the reasons for this fading. X-ray absorption and Mössbauer spectroscopy indicated that the early syntheses lead to Prussian blue together with variable amounts of an undesirable iron(III) product. Pair distribution functional analysis confirmed the presence of nanocrystalline ferrihydrite, Fe10O14(OH)2, and also identified the presence of alumina hydrate, Al10O14(OH)2, with a particle size of ∼15 Å. Paint layers prepared from these pigments subjected to accelerated light exposure showed a tendency to turn green, a tendency that was often reported in eighteenth- and nineteenth-century books. The presence of particles of hydrous iron(III) oxides was also observed in a genuine eighteenth-century Prussian blue sample obtained from a polychrome sculpture.

Imaging by integrating stitched spectrograms

A new diffractive imaging technique called Imaging By Integrating Stitched Spectrograms (IBISS) is presented. Both the data collection and phase retrieval algorithm used in IBISS are direct extensions of frequency resolved optical gating to higher dimensions. Data collection involves capturing an array of diffraction patterns generated by scanning a sample across a coherent beam of light. Phase retrieval is performed using the Principal Components Generalized Projections Algorithm (PCGPA) by reducing the four dimensional data set of images to two remapped two-dimensional sets. The technique is successfully demonstrated using a Helium Neon laser to image a 350μm wide sample with 12μm resolution.

高分解能・高感度X線タイコグラフィー

X-ray ptychography, which is one of the coherent X-ray diffractive imaging techniques, allows us to observe extended objects with a high-spatial resolution and a wide field of view. We have developed high-resolution and high-sensitivity X-ray ptychography using the high-intensity X-ray beam focused by total reflection mirrors at SPring-8. In addition, we have applied it to the elemental mapping of metallic nanoparticles and the imaging of the dislocation strain fields of a silicon film. This method will be available to observe various materials and biological specimen.

Crystallization Kinetics of Superionic Conductive Al(B,La)‐ Incorporated LiTi2(PO4)3 Glass‐Ceramics

For the purpose of developing high‐performance glass‐ceramic superionic conductor, the controllable precipitation of LiTi2(PO4)3‐like superionic conducting phase in the Li2O–TiO2–P2O5 glass system was studied. Al with B or La co‐incorporated LiTi2(PO4)3‐based glass‐ceramics were prepared by the crystallization of the corresponding original glasses. Compared with the sole Al‐incorporated LiTi2(PO4)3‐based glass‐ceramics, the ionic conductivity shows an increase for the boron co‐incorporated one and a decrease for the lanthanum co‐incorporated one. Through the further in‐depth analysis based on the methods of DSC and X‐ray diffractive technique, this opposite change in ion conductivity was ascribed to the alterations of crystallization mechanism together with quantity of crystal phases within the glass‐ceramics.. The boron addition promoted the precipitation of LiTi2(PO4)3 phase and restrained the precipitation of second phase. The highest ionic conductivity 1.3 × 10−3 S/cm at 25°C was obtained through the heat treatment of B and Al co‐incorporated glassy samples at 900°C for 12 h. These inorganic solid electrolytes have a potential application in lithium batteries or other electrochemical ionic devices.

7. An approach to molecular characteristic of collagen mesh extracellular matrix in processed tissue banking, by diffractive techniques

Preservation techniques are of fundamental support for conservation of tissue banking (TB) biological materials. However, controversial views remain on the effects at the molecular level that preservation procedures could produce on the functional structures of tissues. Both programmed cryopreservation and glycerolized tissue preservation are common TB methods in technical preservation. Methodological analysis must be introduced in order to find structural differences in the basic material tissue constitutive collagen to compare potential changes between different procedures. To evaluate comparative final characteristics of programmed cryopreserved vs. glycerolized amnion related to its respective extra cellular matrix (ECM) collagen mesh, using X-ray, and Raman scattering diffractive techniques. Six amnion donors (mean age: 24.33 ± 5.37) were selected according to validated International Standards, informed consent, and clinically controlled normal pregnancy and delivery in accordance with the Ministry of Public Health of Uruguay. Under aseptic conditions amnion tissue was manually dissected from each placenta. Six amnion samples were taken as control: fresh amnion (FAM), stored in saline solution for 24 h, and shipped to DETEMA for diffractographic analysis. Six samples were glycerolized (95%) (GAM) and stored at 4 °C for 30 days. Two amnion samples were processed for cryopreservation (CAM) with RPMI 1640 (90%) and Me 2 SO (10%), and freezing at a controlled rate (1 °C/min) until −142 °C, and stored for 30 days at the same temperature. 30 day amnion samples GAM and CAM, were then shipped for the same diffractographic assays. Defrosting protocol applied to CAM was in accordance with Pegg et al. (Cryobiology 34 (1997) 183–192). Diffractographic analysis was applied and compared with respective profile curves: mean FAM values vs. mean GAM and CAM values calculating OPC values according with Perez Campos et al. (Transplantation Proceedings 40 (2008) 668–674). According to Bragg’s Law, the comparative distance between the planes of the crystalline design of collagen mesh (d space) was calculated relating to each procedure vs. FAM. Additional Raman scattering comparative considerations were obtained. Both GAM and CAM diffractographic curves had the same design related to FAM. However, respective OPC values (FAM vs. GAM = 14.76; and FAM vs. CAM = 42.02) show a higher relative collagen mesh ordering in GAM respective CAM comparing with control FAM. But when comparing the maximum diffractive peak GAM and CAM vs. FAM there was a mismatch with GAM samples of 0.4° in the incidental X-Ray angle: two theta values ( θ ) of Bragg’s Law. On the contrary no mismatch was observed in CAM samples related with FAM. Comparative Raman spectra profiles between FAM and CAM showed punctual differences at ranges of 1260, 1442, and 1667 cm −1 where increased relative intensity values in FAM related to CAM were observed. Conclusions: X-ray diffraction profiles show higher relative ordering of GAM related to CAM but glycerolization modified the structural crystalline design of collagen mesh. Cryopreservation modifies fibril collagen of human amnion I, III and V in chemical residues measured with Raman spectra technique, according to Frank, C. & McCreey, R. (Anal. Chem. 67 (1995) 777–783), and Frushour & Koenig. (Biopolymers 14 (1975) 363–377).

Microarcsecond Astrometry with MCAO Using a Diffractive Mask

AbstractWe present a new ground-based technique to detect or follow-up long-period, potentially habitable exoplanets via precise relative astrometry of host stars using Multi-Conjugate Adaptive Optics (MCAO) on 8 meter telescopes equipped with diffractive masks. MCAO improves relative astrometry both by cancellation of high-altitude atmospheric layers, which induce dynamic focal-plane distortions, and the improvement of centroiding precision with sharper PSFs. However, mass determination of habitable exoplanets requires multi-year reference grid stability of ~1–10 μas or nanometer-level stability on the long-term average of out-of-pupil phase errors, which is difficult to achieve with MCAO (e.g., Meyer et al. 2011). The diffractive pupil technique calibrates dynamic distortion via extended diffraction spikes generated by a dotted primary mirror, which are referenced against a grid of background stars (Guyon et al. 2012). The diffractive grid provides three benefits to relative astrometry: (1) increased dynamic range, permitting observation of V < 10 stars without saturation; (2) calibration of dynamic distortion; and (3) a spectrum of the target star, which can be used to calibrate the magnitude of differential atmospheric refraction to the microarcsecond level. A diffractive 8-meter telescope with diffraction-limited MCAO in K-band reaches < 3–5 μas relative astrometric error per coordinate perpendicular to the zenith vector in one hour on a bright target star in fields of moderate stellar density (~10–40 stars arcmin−2). We present preliminary on-sky results of a test of the diffractive mask on the Nickel telescope at Lick Observatory.

Chemical Contrast in Soft X-Ray Ptychography

The unique strengths of x-ray microscopy are high penetration depth and near-edge resonances that provide chemical information. We use ptychography, a coherent diffractive imaging technique that disposes of the requirement for isolated specimens, and demonstrate resonant imaging by exploiting resonances near the oxygen K edge to differentiate between two oxygen-containing materials. To highlight a biological system where resonant ptychography might be used for chemical mapping of unsliced cells, reconstructions of freeze-dried Deinococcus radiodurans cells at an energy of 517 eV are shown.

Ultrahigh 22 nm resolution coherent diffractive imaging using a desktop 13 nm high harmonic source

New diffractive imaging techniques using coherent x-ray beams have made possible nanometer-scale resolution imaging by replacing the optics in a microscope with an iterative phase retrieval algorithm. However, to date very high resolution imaging (< 40 nm) was limited to large-scale synchrotron facilities. Here, we present a significant advance in image resolution and capabilities for desktop soft x-ray microscopes that will enable widespread applications in nanoscience and nanotechnology. Using 13 nm high harmonic beams, we demonstrate a record 22 nm spatial resolution for any tabletop x-ray microscope. Finally, we show that unique information about the sample can be obtained by extracting 3-D information at very high numerical apertures.

Laser Processing by Using Diffractive Optical Laser Beam Shaping Technique

Laser beam shaping and homogenization techniques are substantial to optimize a large number of laser-material processing applications and laser-material interaction studies. Diffractive optical elements (DOE) play important role in provision of the process-adapted laser beam shaping. In this paper, we present an approach for laser beam shaping by using innovative DOE. The circular Gaussian beam was transformed to a square flat-top intensity profile in the focal plane of the objective lens by using novel DOE from TOPAG Lasertechnik GmbH. About 95% of the laser energy was coupled in the main beam with a nearly perfect rectangular shape. Experimental results have been achieved by applying the shaped beam for laser microfabrication. The picosecond and nanosecond lasers with moderate beam quality (M 2 =1.5) were used in the experiment. The shaped laser beam was applied for direct laser ablation of metal film on the glass substrate, drilling in a silicon wafer, scribing of thin-film solar cells and other technical materials. This technique allows creating a rectangular-shaped flat-top intensity profile in the focal plane that shows distinct advantages in laser material processing.

Wave-front phase retrieval in transmission electron microscopy via ptychography

There are many different strategies that allow the solving of the well-known phase problem corresponding to the loss of phase information during a physical measurement. In microscopy, and, in particular, in transmission electron microscopy, most of these strategies focus on the retrieval of high-resolution information with the importance of lower resolution data often overlooked. Ptychography offers a means to investigate such data. Ptychography is a robust diffractive imaging technique with fast convergence for phase retrieval but, until now, has not been applied at the nanoscale. In this paper, we use the ptychographical iterative engine to retrieve the phase change at the exit plane of metallic nanoparticles using a conventional transmission electron microscope. Ptychographical reconstructions yielded images with a phase resolution of $\ensuremath{\pi}/10$ and a spatial resolution of 1 nm. These results stand as a first step toward aberration-free lensless imaging. The technique lends itself to be an alternative to off-axis electron holography or focal series reconstruction.

Optical ptychography: a practical implementation with useful resolution

Quantitative phase microscopy offers a range of benefits over conventional phase-contrast techniques. For example, changes in refractive index and specimen thickness can be extrapolated and images can be refocused subsequent to their recording. In this Letter, we detail a lensless, quantitative phase microscope with a wide field of view and a useful resolution. The microscope uses the recently reported coherent diffractive imaging technique of ptychography to generate images from recorded diffraction patterns.

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

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.

The potential for two-dimensional crystallography of membrane proteins at future x-ray free-electron laser sources

Ultrashort pulses from x-ray free-electron laser (XFEL) sources promise to assist in obtaining the structures of membrane proteins at high resolution. We have reconstructed the electron density distribution of a two-dimensional (2D) aquaporin crystal from simulated XFEL data using ptychography, a diffractive imaging technique based on multiple exposures. Increasing the number of exposures compensates for Poisson noise, indicating that the achievable resolution is limited by the reproducibility of the crystals. This technique should therefore be applicable at all future ultrashort-pulsed hard x-ray sources.

Fresnel coherent diffractive imaging: treatment and analysis of data

Fresnel coherent diffractive imaging (FCDI) is a relatively recent addition to the suite of imaging tools available at third generation x-ray sources. It shares the strengths of other coherent diffractive techniques: resolution limits that are independent of focusing optics, single-plane measurement and high dose efficiency. The more challenging experimental geometry and detailed reconstruction algorithms of FCDI provide enhanced numerical stability and convergence properties to the iterative algorithms commonly used. Experimentally, a diverging beam is utilized, which facilitates sample alignment and allows the imaging of extended samples. We describe the underlying physics and assumptions that give rise to the FCDI iterative reconstruction algorithms, as well as their implications for the design of a successful FCDI experiment.

Structural inhomogeneity in silicon-on-insulator probed with coherent X-ray diffraction

We report our research on X-ray micro-beam diffraction and coherent X-ray diffractive imaging techniques to study structural inhomogeneities in Silicon-On-Insulator continuous plain wafers. Inhomogeneities were measured quantitatively and attributed to limitations of the manufacturing process. 3-dimensional image reconstructions were performed by using our Error-Reduction and Hybrid-Input-Output iterative algorithms. These revealed images of the focussed X-ray beam passing through the active layer of the wafer.

Near diffraction limited coherent diffractive imaging with tabletop soft x-ray sources

Tabletop coherent x-ray sources hold great promise for practical nanoscale imaging, in particular when coupled with diffractive imaging techniques. In initial work, we demonstrated lensless diffraction imaging using a tabletop high harmonic generation (HHG) source at 29 nm, achieving resolutions ∼ 200 nm. In recent work, we significantly enhanced our diffractive imaging resolution by implementing a new high numerical aperture (up to NA=0.6) scheme and field curvature correction where we achieved sub-100 nm resolution. Here we report the first demonstration of Fourier transform holography (FTH) with a tabletop SXR source, to acquire images with a resolution ≈ 90 nm. The resolution can be refined by applying phase retrieval. Additionally, we show initial results from FTH with 13.5 nm HHG radiation and demonstrate ∼ 180 nm resolution.

Well-Defined Galactose-Containing Multi-Functional Copolymers and Glyconanoparticles for Biomolecular Recognition Processes

We report here the syntheses of galactose-containing polymers via reversible addition−fragmentation chain transfer process. Diblock copolymers with one galactose-containing chain segment and one primary amine-containing or linear glucose-containing chain segment were prepared via chain extension technique. Primary amine pendant groups of the copolymer were further modified with biotinyl-N-hydroxysuccinimide ester. Subsequently, multifunctional glyconanoparticles were prepared and used in the study of biomolecular recognition processes. The biomolecular recognition of the biotin and galactose moiety on the surface of the glyconanoparticles toward avidin and Ricinus communis agglutinin lectin respectively was confirmed using UV−visible spectroscopy and diffractive optics techniques. It was found that both carbohydrate-carbohydrate and carbohydrate−protein interactions increased with increasing divalent salt (Ca2+ and Mn2+) concentration.

Three Metabolites from the Mangrove Endophytic Fungus Sporothrix sp. (#4335) from the South China Sea

Three metabolites, sporothrins A, B, and C (1-3), were isolated from the mangrove endophytic fungus Sporothrix sp. (#4335). Their structures were identified by the spectral data and X-ray diffractive techniques, with compound 1 showing strong inhibition of acetylcholine esterase. 1,3,6,8-Tetrahydroxynaphthalene (T4HN) was deduced as one of the precursors in the biosynthesis of 1 and 2. In a primary biosynthesis gene study, the partial gene fragment obtained with the LC1-Im/2c-Im primer pair was shown to be closely related to genes encoding T4HN synthase. The deduced protein sequences were highly homologous to the ketosynthase domains of other fungal PKS genes involved in T4HN biosynthesis.