A5052841360- Advanced X-ray Imaging Techniques
- Photonic and Optical Devices
- Nanofabrication and Lithography Techniques
- Thin-Film Transistor Technologies
- Photonic Crystals and Applications
- Advancements in Photolithography Techniques
- Advanced Electron Microscopy Techniques and Applications
- Advanced Surface Polishing Techniques
- Optical measurement and interference techniques
- Nanowire Synthesis and Applications
- Digital Holography and Microscopy
- Optical Coatings and Gratings
- Silicon and Solar Cell Technologies
- High-pressure geophysics and materials
- Silicon Nanostructures and Photoluminescence
- Semiconductor Lasers and Optical Devices
- Nuclear Physics and Applications
- Medical Imaging Techniques and Applications
- Force Microscopy Techniques and Applications
- Advanced Memory and Neural Computing
- Analytical Chemistry and Sensors
- Acoustic Wave Resonator Technologies
- Advanced Fiber Laser Technologies
- Ferroelectric and Negative Capacitance Devices
- Mechanical and Optical Resonators
University of Cambridge
2023-2025
Institute for Biomedical Engineering
2020-2024
ETH Zurich
2020-2024
Photonic Science (United Kingdom)
2023
Paul Scherrer Institute
2020-2023
General Research Institute for Nonferrous Metals (China)
2015
Fudan University
2007
University of Oxford
1994-1996
Refraction-based x-ray imaging can overcome the fundamental contrast limit of computed tomography (CT), particularly in soft tissue, but so far has been constrained to high-dose ex vivo applications or required highly coherent sources, such as synchrotrons. Here we demonstrate that grating interferometry (GI) is more dose efficient than conventional CT human breast under close-to-clinical conditions. Our system, based on a source and commercial gratings, outperformed for spatial resolutions...
The key optical components of X-ray grating interferometry are gratings, whose profile requirements play the most critical role in acquiring high quality images. difficulty etching lines with aspect ratios when pitch is range a few micrometers has greatly limited imaging applications based on interferometry. A rate low ratio dependence crucial for higher energy and good control by deep reactive ion patterns. To achieve this goal, modified Coburn–Winters model was applied order to study...
Structuring Si in arrays of vertical high aspect ratio pillars, ranging from nanoscale to macroscale feature dimensions, is essential for producing functional interfaces many applications. Arrays silicon 3D nanostructures are needed realize photonic and phononic crystals, waveguides, metalenses, X-ray wavefront sensors, detectors. In particular, nanopillars used as bio-interfaces neural activity recording, cell culture, microfluidics, sensing on-chip manipulation. Here, we demonstrate a...
Recent years have seen the rapid development of miniaturized reconstructive spectrometers (RSs), yet they still confront a range technical challenges, such as bandwidth/resolution ratio, sensing speed, and/or power efficiency. Reported RS designs often suffer from insufficient decorrelation between sampling channels, which, in essence, is due to inadequate engineering responses. This turn results poor spectral-pixel-to-channel ratios (SPCRs), typically restricted at single digits. So far,...
We present two spatial-multiplexed switch-and-select (S&S) 8x8 optical switches incorporating a tri-layer SiN-on-Si platform, one equipped with thermo-optic (T-O) and the other electro-optic (E-O) switching elements. To best of our knowledge, switch fabric is first-of-its-kind device assembled in such multi-layer platform. The shuffle between multiplexer demultiplexer array established via Si-SiN-SiN structure, creating three-dimensional crossing-free photonic network. At same time,...
Abstract The multi-scale characterization of building materials is necessary to understand complex mechanical processes, with the goal developing new more sustainable materials. To that end, imaging methods are often used in science characterize microscale. However, these compromise volume interest achieve a higher resolution. Dark-field (DF) contrast being investigated length scales smaller than resolution system, allowing direct comparison features nano-scale range and overcoming scale...
The application of superconformal Bi-catalyzed Au electrodeposition for void-free filling recessed trenches in X-ray gratings used phase contrast imaging is detailed. Filling with aspect ratio (height divided by width) up to 55 demonstrated. Uniform bottom-up patterned trench arrays across 100 mm (4 inch) diameter Si wafer accomplished using a well-defined hydrodynamic flow field the surface. process and microstructure are examined scanning electron microscopy cross-sectioned specimens....
Abstract Respiratory diseases are one of the most common causes death, and their early detection is crucial for prompt treatment. X-ray dark-field radiography (XDFR) a promising tool to image objects with unresolved micro-structures such as lungs. Using Talbot-Lau XDFR, we imaged inflated porcine lungs together Polymethylmethacrylat (PMMA) microspheres (in air) diameter sizes between 20 500 $$\upmu \hbox {m}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow>...
We report a delayed-switch-on effect in organic memories; i.e., the memory devices can automatically switch from off state to on after certain period of time when biased at voltages below threshold voltage. Meanwhile, lower voltage is, longer switching will be. The scales milliseconds about 104s with decreasing Moreover, by applying between and Vmax, intermediate states are also obtained. existence filamentary microconducting channels layer is proposed be responsible for observed phenomenon.
We present a method to produce small pitch gratings for X-ray interferometric imaging applications, allowing the phase sensitivity be increased and/or length of laboratory setup minimized. The is based on fabrication high aspect ratio silicon microstructures using deep reactive ion etching (Bosch technique) dense grating arrays and followed by conformal electroplating Au. demonstrated that low resistivity Si substrates (<0.01 Ohm·cm) enable metal seeding layer deposition step avoided, which...
The anisotropic nature of plasma etching is usually exploited to realize vertical nano-/micro- silicon structures by deep reactive ion etching. However, some applications require tilted instead perpendicular profiles with respect the substrate. Here, a controlled realized introducing set metal electric field modulator(s), which modify near sample surface potential. ions from body are accelerated under influence distorted field, and hit certain incident angle. A model built finite elements...
In this paper, we use amorphous Gd2O3 as the switching layer for fabricated RRAM devices with novel high performance, excellent flexibility, and mechanical endurance properties potential candidate memory flexible electronics applications. The obtained Cu/Gd2O3/Pt on polyethylene terephthalate (PET) substrates show bipolar characteristics, low voltage operation (<2 V) long retention time (>106 s). No performance degradation occurs, stored information is not lost after device has been bent to...
Abstract Displacement Talbot lithography can rapidly pattern periodic nanostructures with high depth of focus over large area. Imperfections in the phase mask profile and stage movement inaccuracies during exposure cause linewidth variation every second line binary gratings. While this beating is barely visible patterned photoresist, it leads to substantial when transferred into aspect ratio silicon structures, because micro-loading deep reactive ion etching. A proper scan range compensated...
Microstructural information over an entire sample is important to understand the macroscopic behaviour of materials. X-ray scattering tensor tomography facilitates investigation microstructural organisation in statistically large volumes. However, established acquisition protocols based on scanning small-angle and grating interferometry inherently require long scan times even with highly brilliant sources. Recent developments diffractive optics towards circular pattern arrays enable fast...
The orientation mismatch between the cone beam of an X-ray tube and grating lines in a flat substrate remains big challenge for laboratory grating-based interferometry, since it severely limits imaging field view. Here, we fabricated fan-shaped <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msub> <mml:mi mathvariant="normal">G</mml:mi> </mml:mrow> <mml:mn>0</mml:mn> </mml:msub> </mml:math> source gratings by modulating...
An extreme bottom-up filling variant of superconformal Au electrodeposition yielding void-free recessed features is demonstrated with diffraction gratings composed a two-dimensional patterned "chessboard" array square vias aspect ratio (depth/width) ≈ 23 as well one-dimensional arrays trenches having ratios exceeding 50 and 65. Deposition on planar substrates examined in several near-neutral x moll−1 Na3Au(SO3)2 + 0.64 Na2SO3 electrolytes (x = [0.08, 0.16, 0.32]) containing ≈50 μmoll−1 Bi3+...
Precisely aligned optical components are crucial prerequisites for X-ray tomography at high resolution. We propose a device with fractal pattern precise automatic focusing. The is etched in Si substrate by deep reactive ion etching and then filled self-terminating bottom-up Au electroplating process. nature of the produces an transmission image globally homogeneous macroscopic visibility local contrast pixel sizes range 0.165 µm to 11 µm, while absorption provided between enables its use...
Dual-phase x-ray grating interferometry (DP-XGI) is a recently developed imaging technique that can retrieve structural information in the sub-micro scale over areas millimeter range. This performed by use of scattering signal, which sensitive to structures lie below intrinsic spatial resolution system. A quantitative understanding microstructure possible when signal retrieved within range auto-correlation lengths features interest. High visibility fringes this length desirable, but no...
X-ray dark-field and phase contrast imaging using grating interferometry (GI) have demonstrated great potential for medical industrial applications. GI relies on the fabrication of high-quality absorption gratings, which has revealed to be quite challenging. This paper proposes an interferometer differential a single phase-shifting element. proposal simplifies setup without penalizing image quality. The proposed consists dual-period having two distinct periods, generates intensity modulation...
A large amount of valuable research on black silicon (b-Si) nanostructures has pushed its use further into application in recent years. However, the results to be found are all related plane substrates. For an investigation b-Si structures curved surfaces, they were fabricated hemispherical lenses using inductively coupled plasma reactive ion etching. It was possible achieve different structure morphologies according selected etching parameters, analogous their fabrication Si wafers....
We report a Si-SiN-SiN tri-layer switch-and-select 8×8 optical switch with 128 thermally-driven microring-resonators. Crosstalk ratio and on-chip loss are measured in the range of -33.2 to -50.8dB 2.1 10.5dB, respectively, >70GHz passband.