Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Keith A. NugentARC Centre of Excellence for Coherent X-ray Science & School of Physics

The University of Melbourne

Australia

Opportunities for imaging with Opportunities for imaging with coherencecoherence

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Outline of TalkOutline 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

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Approaches to Coherent Imaging

• 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

To Image extended objects in three-dimensions with 5nm resolution

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Coherent imaging methods are being developed.

z

Coherent Field Impose Measure Intensity, Keep PhaseImpose Measure Intensity, Keep Phase

Impose “support”Impose “support” Guess PhaseGuess Phase

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Use prior knowledge of the incident wave to recover the “exit surface wave” leaving the object

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

The World’s Easiest CDI Experiment

FourierFourierFresnelFresnel

FresnelFresnel

FourierFourier

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Reconstruction of the Illuminating FieldReconstruction of the Illuminating Field

HM Quiney, AG Peele, Z Cai, D Paterson, KA Nugent, Nature Physics, 2, 101-104 (2006)

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

X-Ray CDI

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

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)

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Quantitative Phase MeasurementQuantitative 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 ± 292 344 ± 7 377 ± 283 308 ± 15 297 ± 324 348 ± 12 321 ± 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.

Clark, J.N., et al., Quantitative phase measurement in coherent diffraction imaging. Optics Express, 2008. 16(5) 3342-3348.

Use prior knowledge of the incident wave to recover the “exit surface wave” leaving the object

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

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.

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Optical Demonstration

Diode Laser Beam

Optical Test Chart

CCD Camera

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Independent Fresnel CDI images of a large object

Experimental data obtained using coherent visible

light

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

X-Ray CDI

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Have Have achieved a achieved a

resolution of resolution of ~15nm!~15nm!

B Abbey et al, “Keyhole Coherent Diffractive Imaging”, Nature Physics, Published on the web March 9, 2008

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Exceeds Exceeds resolution of resolution of STXM with STXM with

same optics, same optics, by a factor of by a factor of

~4!~4!

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Images of a fuse-bay sampleImages of a fuse-bay sample

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

All of the conceptual and All of the conceptual and methodological pieces are in methodological pieces are in

place for us to achieve 3D place for us to achieve 3D imaging of extended objects imaging of extended objects with 5nm spatial resolutionwith 5nm spatial resolution

Coherent X-ray Diffraction Workshop, BNL, May 14 2008

Collaborators

• Harry Quiney (UM)Harry Quiney (UM)• Andrew Peele (La Trobe)Andrew Peele (La Trobe)• Garth Williams (UM) Garth Williams (UM) • Lachlan Whitehead (UM)Lachlan Whitehead (UM)

• Brian Abbey (UM)Brian Abbey (UM)

• Jesse Clark (La Trobe)Jesse Clark (La Trobe)

• David Paterson David Paterson

(Australian Synchrotron)(Australian Synchrotron)

• Martin de Jonge (APS – Martin de Jonge (APS –

Now AS)Now AS)

• Ian McNulty (APS)Ian McNulty (APS)

• Z Cai (APS)Z Cai (APS)

• Leann Tilley (La Trobe)Leann Tilley (La Trobe)

• Eric Hanssen (La Trobe)Eric Hanssen (La Trobe)