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Coherent X-Ray Diffraction Imaging Kevin Raines University of California, Los Angeles Compton Sources for X/gamma Rays: Physics and Applications Alghero 7-12 September 2008
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Preliminaries
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The First Compound Light Microscope 1611 Kepler suggested that a compound light microscope could be constructed based on a three lenses conformation. 1665 Hooke built the 1st compound light microscope and imaged small pores in sections of cork he called “cells” Hooke’s compound light microscope and a drawing of cork made by Hooke.
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Discovery of X-Rays: Röntgen Development of X-ray Crystallographic Microscope
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Some Important Dates in the History of Optics Ancient Times – Quantization & Empty Space; Minimization principles ~450 B.C. Empedocles – Speed of light is finite ~100 B.C. Claudius Ptolemaeus – Law of refraction for small angles Pre-modern – Corpuscular theory, Geometrical Optics ~1500 Da Vinci – Camera Obscura ~1660 Hooke – First lensed microscope Early Modern – Wave Theory, Fourier Optics, Ether ~1640 Huygens – Early wave theory advocate ~1800 Fresnel – Diffraction Theory ~1850 Faraday, Maxwell – Electromagnetic theory of light ~1880 Abbe – Early Fourier Optics 1895 Rontgen – Discovery of x-Rays Modern Theory – Quantum, Fourier, & Statistical Optics ~1900 Plank, Einstein – Quantization, special relativity ~1930 Schrodinger, Heisenberg – Quantum mechanics ~1960 Maiman – Laser
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Fourier Optics + Coherent X-Rays = CXDI Complex Amplitude from interference of light scattered from each atom (superposition principle) Only time-averaged intensity of field is measurable – phase information is lost.
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The Importance of the Phase Information (a) (b)
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The Importance of the Phase Information (a) (b) Fourier amplitude of (a) + Fourier phases of (b) Fourier amplitude of (b) + Fourier phases of (a)
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X-ray Diffraction by Crystals Laue, W. Bragg and L. Bragg, 1912 |FT| a 1 /a N N Discrete Bragg Intensities Periodic Structure
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Diffraction by Non-periodic structures 1 /a a N N Continuous Frequency Spectrum Non-Periodic Structure
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Shannon Sampling vs. Bragg Sampling FT Shannon Sampling Theorem, 1949 a 1 /a FT -1 Nyquist Frequency
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Shannon Sampling vs. Bragg Sampling FT Shannon Sampling Theorem, 1949 a 1 /a |FT| a Bragg Sampling 1 /a FT -1 Nyquist Frequency
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Bragg-peak Sampling vs. Oversampling |FT| Indistinguishable a a 1 /a
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Bragg-peak Sampling vs. Oversampling |FT| Indistinguishable a a 1 /a Distinguishable < 1 /a
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A Pictorial Representation of the Oversampling Method Reciprocal Space Real Space
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The Physical Explanation to the Oversampling Method Real Space Reciprocal Space Nyquist sampling frequency Miao, Sayre & Chapman, J. Opt. Soc. Am. A 15, 1662 (1998). Oversampling Better coherence More correlated intensity points Phase information Miao, Sayre & Chapman, J. Opt. Soc. Am. A 15, 1662 (1998).
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A New Type of Microscopy – Lensless Imaging X-rays, electrons or lasers Coherent Scattering An object Solving the phase problem
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A Brief History of the Oversampling Method 1952 Sayre, Acta Cryst. 5, 843. Suggested that measuring the intensity at as well as between the Bragg peaks may provide the phase information. 1978Fienup, Opt. Lett. 3, 27. Developed an iterative algorithm for phase retrieval of diffraction intensity. 1998Miao et al. J. Opt. Soc. Am. A 15, 1662. Proposed an explanation to the oversampling method. 1999Miao et al., Nature 400, 342. First experimental demonstration of the oversampling method and lensless imaging.
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i) Start with 16 independent reconstructions. ii) For each reconstruciton: Real Space Reciprocal Space iii) Calculate the R-value, iv) Select a seed out of 16 images ( seed ) with the smallest R-value. v) FFT FFT -1 Chen, Miao, Wang & Lee, PRB 76, 064113 (2007). i = 1, 2, …, 16 The Guided Hybrid Input-Output (GHIO) Algorithm
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Image Reconstruction Using the GHIO Algorithm at 0 th Generation
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Image Reconstruction Using the GHIO Algorithm at 8 th Generation
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Temporal (or longitudinal) coherence Spatial (or transverse) coherence 180° phase shift ltlt d x
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Young’s Double Slit Experiment
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Double Slit: Two Sources
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Oversampling Tightens Coherence Requirements
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3D imaging via X-ray Coherent Imaging
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Compounded Inverse Problems: The phase problem – Non-linear inverse problem; diffraction data in principle has less information than a projection. Solve phases – get projections. The tomography problem – Inverse Radon Transfrom: - Less meaningful data (i.e. no simple interpretation like a projection.) Missing Data Problem – Far less data than CT. Diffraction Tomography
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Oversampling is the key Oversampling by greater than 2 uniquely encodes the phases Iterative computer algorithms efficiently recover the phases Oversampling + constraints eliminates much of the missing data problem (simulations show only 30% of the data is needed.) 3 major inverse problem reduced to one straightforward computational problem: interpolation Diffraction Tomography
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Radiation Studies for Biological Imaging
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Diffraction Tomography
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Oversampled diffraction pattern from a GaN quantum dot nanoparticle AFM Image of GaN quantum dots, showing the platelet structures. Coherent X-ray Diffraction Pattern from a GaN Quantum Dot Particle
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3D Surface Morphology of the GaN Quantum Dot Nanoparticle
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Quantitative 3D Internal View of the GaN Quantum Dot Nanoparticle
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Outline of Current CXDI Projects - Biological Imaging i. Whole, unstained cells at ~ 10 nm res. ii. Single unstained virions at < 1 nm res. iii. Single biomolecule imaging - Materials & Dynamic Imaging i. Femtosecond pulses. ii. Resonant imaging (atomic specificity) - Electron Diffraction - Tabletop Sources
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Schematic Layout of Resonant X-ray Diffraction Microscopy
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Coherent X-ray Diffraction Pattern of a Bi Doped Si Crystal with E = 2.55 keV
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Part of X-ray Diffraction Patterns with E=2.550 and 2.595 keV E=2.550 keV E=2.595 keV
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Elemental Mapping of Buried Bi Structure Song, Bergstrom, Ramuno-Johnson, Jiang, Paterson, de Jonge, McNulty, Lee, Wang & Miao, PRL 100, 025504 (2008).
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Experimental Setup for Imaging Single Herpesviruses
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Coherent Imaging of a Single Unstained Herpesvirus
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Identifying the Viral Capsid Inside the Herpesvirus Quantitative X-ray diffraction imaging of a single herpesvirus AFM image of a herpesvirus prepared at the same conditions Song, Jiang, Mancuso, Amirbekian, Peng, Sun, Shah, Zhou, Ishikawa & Miao, PRL in press.
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Experimental Setup of Tabletop Lensless Imaging Using a HHG Source
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Sandberg et al., PRL 99, 098103 (2007). First Experimental Demonstration of Tabletop Lensless Imaging
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Tabletop Lensless Imaging at 71 nm Resolution (~1.5 ) with an EUV Laser Source
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Sandberg et al., PNAS 105, 24 (2008)..
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A Potential Set-up for Imaging Single Biomolecules Using X-FELs Radiation Damage Solemn & Baldwin, Science 218, 229 (1982). Neutze et al., Nature 400, 752 (2000). When an X-ray pulse is short enough ( ~ 10 fs), a 2D diffraction pattern may be recorded from a molecule before it is destroyed. X-FEL Pulses X-ray Lens Molecular Spraying Gun CCD
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Summary Oversampling the diffraction intensities the phase information. Imaged nanostructured materials and biological structures in two and three dimensions. Electron diffraction microscopy imaging a DWNT at 1 Å resolution. Future: imaging single particles by using the X-ray free electron lasers or electrons.
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Collaborators UCLA Physics & AstronomyC. Song, H. Jiang, A. Mancuso, R. Xu, K. Raines, S. Salha, B. Amirbekian RIKEN/SPring-8T. Ishikawa, Y. Nishino, Y. Kumara University of Colorado, Boulder M.M. Murnane, H.C. Kapteyn, R.L. Sandberg Colorado State University J.J. Rocca’s group APS, ANLI. NcNulty, M.D. de Jonge, D. Paterson UCLA, Electric EngineeringK. Wang UC, DavisS. Risbud CXO, LBNLA.E. Sakdinawat Academia Sinica, Taiwan C.C. Chen, T.K. Lee UCLA Medical SchoolR. Sun, Z.H. Zhou, P. Li, F. Tamanoi Harvard Medical School M.J. Glimcher, L. Graham
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Coherent Imaging Group @ UCLA
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