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Opportunities for imaging with coherence

Opportunities for imaging with coherence. Keith A. Nugent ARC Centre of Excellence for Coherent X-ray Science & School of Physics The University of Melbourne Australia. Outline of Talk. What can we aim for in 2013? Introduction to CDI – brief Fresnel CDI (FCDI)

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Opportunities for imaging with coherence

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  1. Opportunities for imaging with coherence Keith A. Nugent ARC Centre of Excellence for Coherent X-ray Science & School of Physics The University of Melbourne Australia

  2. Outline of Talk • What can we aim for in 2013? • Introduction to CDI – brief • Fresnel CDI (FCDI) • Quantitative phase measurement • Application to malaria-infected red blood cell • Keyhole FCDI – imaging extended objects • Application to technology problem • Early 3D results • Conclusions

  3. Approaches to Coherent Imaging To Image extended objects in three-dimensions with 5nm resolution • Holography • Recent work at BESSY • Limited path to high resolution • Phase-contrast • Very extensively used • Low resolution • Ptychography • SLS – Oliver Bunk • Extended objects, high resolution? • CDI • Plane wave incident • Isolated objects • Curved incident wave

  4. Coherent imaging methods are being developed. Coherent Field Impose Measure Intensity, Keep Phase z Impose “support” Guess Phase

  5. Unique! Use prior knowledge of the incident wave to recover the “exit surface wave” leaving the object

  6. The World’s Easiest CDI Experiment Fourier Fresnel Fresnel Fourier

  7. Reconstruction of the Illuminating Field HM Quiney, AG Peele, Z Cai, D Paterson, KA Nugent, Nature Physics, 2, 101-104 (2006)

  8. X-Ray CDI

  9. Fresnel diffraction imaging GJ Williams, HM Quiney, BB Dahl, CQ Tran, KA Nugent, AG Peele, D Paterson, M de Jonge, Physical Review Letters, 97, 025506 (2006)

  10. Quantitative Phase Measurement Average AFM height and reconstructed thickness for the four areas indicated in Fig 2(c). Region AFM (nm) FCDI (nm) 1 370 ± 8*360 ± 29 2 344 ± 7377 ± 28 3 308 ± 15297 ± 32 4 348 ± 12321 ± 19 *Errors are estimated from the variance in the heights recovered within each region, as this includes intrinsic height variation the errors are therefore conservative. Use prior knowledge of the incident wave to recover the “exit surface wave” leaving the object Clark, J.N., et al., Quantitative phase measurement in coherent diffraction imaging. Optics Express, 2008. 16(5) 3342-3348.

  11. What do we mean by “support”? Support is interpreted slightly differently here –the structure to be reconstructed is the coherent exit wave, including the illumination, not the scattering object itself.

  12. Optical Demonstration CCD Camera Diode Laser Beam Optical Test Chart

  13. Independent Fresnel CDI images of a large object Experimental data obtained using coherent visible light

  14. X-Ray CDI

  15. Have achieved a resolution of ~15nm! B Abbey et al, “Keyhole Coherent Diffractive Imaging”, Nature Physics, Published on the web March 9, 2008

  16. Exceeds resolution of STXM with same optics, by a factor of ~4!

  17. Images of a fuse-bay sample

  18. All of the conceptual and methodological pieces are in place for us to achieve 3D imaging of extended objects with 5nm spatial resolution

  19. Collaborators • Harry Quiney (UM) • Andrew Peele (La Trobe) • Garth Williams (UM) • Lachlan Whitehead (UM) • Brian Abbey (UM) • Jesse Clark (La Trobe) • David Paterson (Australian Synchrotron) • Martin de Jonge (APS – Now AS) • Ian McNulty (APS) • Z Cai (APS) • Leann Tilley (La Trobe) • Eric Hanssen (La Trobe)

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