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Electron microscopy has become a pivotal tool in numerous fields of study, from
materials to biological imaging. While these static images have indeed pushed
the frontiers of knowledge, structure-function relationships can only be
inferred; integration of the fourth dimension (time) with the three spatial
dimensions is necessary for a more rigorous understanding of the forces behind
the function. For this reason, we introduced the concept of single electron
imaging for the development of four-dimensional ultrafast electron microscopy
(UEM). Because single-electron packets have no space-charge broadening, images
and diffraction patterns can be observed with atomic-scale spatial resolution
and with the time resolution being fundamentally determined by the ultrashort
duration of the optical pulse used to generate electrons in the microscope.
The main focus of research is on the study of nonequilibrium structural phase
transitions, nanometer-scale phenomena, and biological imaging (see abstracts below). With two
microscopes, UEM1 and UEM2, several research areas are being explored,
including single-pulse imaging for irreversible structural change. UEM2,
Caltech's second generation ultrafast electron microscopy laboratory, has been
designed to expand the scope of ultrafast applications by achieving
atomic-scale resolution in ultrafast real-space imaging for the first time, and
by the added capabilities of electron-energy-loss spectroscopy (EELS),
energy-filtered-UEM, and scanning transmission UEM. The same instrument was
augmented with two ns lasers extending the mode of operation from
single-electron to single-pulse and the time resolution to from fs to s. The
first study using UEM2 involved the above features to obtain atomic-scale
resolution in real space images, elemental mapping, and electron-energy
filtering. We have obtained images of protein crystals with UEM2, and also
reported on the direct visualization of embryonic crystallizarion in different
materials using the single-pulse mode of UEM2.
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Selected Publications
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Entangled nanoparticles: Discovery by visualization in 4D electron microscopy, A. Yurtsever, J. S. Baskin, A. H. Zewail, Nano Lett. 2012,
12, 5027-5032.
[Web link] [Abstract] [Top of page]
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Relativistic effects in photon-induced near field electron microscopy, S. T. Park, A. H. Zewail, J. Phys. Chem. A 2012,
116, 11128-11133.
[Web link] [Abstract] [Top of page]
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Ultrafast Kikuchi diffraction: Nanoscale stress-atrain dynamics of wave-guiding structures, A. Yurtsever, S. Schäfer, A. H. Zewail, Nano Lett. 2012,
12, 3772-3777.
[Web link] [Abstract] [Top of page]
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Direct visualization of near-fields in nanoplasmonics and nanophotonics, A. Yurtsever, A. H. Zewail, Nano Lett. 2012,
12, 3334-3338.
[Web link] [Abstract] [Top of page]
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4D electron microscopy visualization of anisotropic atomic motions in carbon nanotubes, S. T. Park, D. J. Flannigan, A. H. Zewail, J. Am. Chem. Soc. 2012,
134, 9146-9149.
[Web link] [Abstract] [Top of page]
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Chirped imaging pulses in four-dimensional electron microscopy: Femtosecond pulsed hole burning, S. T. Park, O.-H. Kwon, A. H. Zewail, New J. Phys. 2012,
14, 053046.
[Web link] [Abstract] [Top of page]
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Subparticle ultrafast spectrum imaging in 4D electron microscopy, A. Yurtsever,
R. M. van der Veen, A. H. Zewail, Science 2012,
335, 59-64.
[Web link] [Abstract] [Top of page]
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Enhancing image contrast and slicing electron pulses in 4D near field electron microscopy,
S. T. Park, A. H. Zewail, Chem. Phys. Lett.
2012, 521, 1-6.
[Web link] [Abstract] [Top of page]
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4D scanning transmission ultrafast electron microscopy: Single particle imaging and spectroscopy, V. Ortalan, A. H. Zewail, J. Am. Chem. Soc. 2011,
133, 10732-10735.
[Web link] [Abstract] [Top of page]
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4D scanning ultrafast electron microscopy: Visualization of materials surface dynamics, O. F. Mohammed, D.-S. Yang, S. K. Pal, A. H. Zewail, J. Am. Chem. Soc. 2011,
133, 7708-7711.
[Web link] [Abstract] [Top of page]
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Nanomusical systems visualized and controlled in 4D electron microscopy, J. S. Baskin, H. S. Park, A. H. Zewail, Nano Lett. 2011,
11, 2183-2191.
[Web link] [Abstract] [Video] [Top of page]
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Macromolecular structural dynamics visualized by pulsed dose control in 4D electron microscopy, O.-H. Kwon, V. Ortalan, A. H. Zewail, Proc. Natl. Acad. Sci. USA 2011,
108, 6026-6031.
[Web link] [Abstract] [Top of page]
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Irreversible chemical reactions visualized in space and time with 4D electron microscopy, S. T. Park, D. J. Flannigan, A. H. Zewail, J. Am. Chem. Soc. 2011,
133, 1730-1733.
[Web link] [Abstract] [Top of page]
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Kikuchi ultrafast nanodiffraction in four-dimensional electron microscopy, A. Yurtsever, A. H. Zewail, Proc. Natl. Acad. Sci. USA 2011,
108, 3152-3156.
[Web link] [Abstract] [Top of page]
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4D Lorentz electron microscopy imaging: Magnetic domain wall nucleation, reversal, and wave velocity, H. S. Park, J. S. Baskin, A. H. Zewail, Nano Lett. 2010,
10, 3796-3803.
[Web link] [Abstract] [Video] [Top of page]
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Nonchaotic nonlinear motion visualized in complex nanostructures by stereographic 4D electron microscopy, O.-H. Kwon, H. S. Park, J. S. Baskin, A. H. Zewail, Nano Lett. 2010,
10, 3190-3198.
[Web link] [Abstract] [Video] [Top of page]
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Scanning ultrafast electron microscopy, D.-S. Yang, O. F. Mohammed, A. H. Zewail, Proc. Natl. Acad. Sci. USA 2010,
107, 14993-14998.
[Web link] [Abstract] [Top of page]
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Nanofriction visualized in space and time by 4D electron microscopy, D. J. Flannigan, S. T. Park, A. H. Zewail, Nano Lett. 2010,
10, 4767-4773.
[Web link] [Abstract] [Top of page]
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Biological imaging with 4D ultrafast electron microscopy, D. J. Flannigan, B. Barwick, A. H. Zewail, Proc. Natl. Acad. Sci. USA 2010,
107, 9933-9937.
[Web link] [Abstract] [Top of page]
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Optomechanical and crystallization phenomena visualized with 4D electron microscopy: Interfacial carbon nanotubes on silicon nitride, D. J. Flannigan, A. H. Zewail, Nano Lett. 2010,
10, 1892-1899.
[Web link] [Abstract] [Video] [Top of page]
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Photon-induced near-field electron microscopy, B. Barwick, D. J. Flannigan, A. H. Zewail, Nature 2009,
462, 902-906.
[Web link] [Abstract] [Video] [Top of page]
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4D nanoscale diffraction observed by convergent-beam ultrafast electron microscopy, A. Yurtsever, A. H. Zewail, Science 2009,
326, 708-712.
[Web link] [Abstract] [Top of page]
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Earlier Studies
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