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Research Highlights

Femtobiology & Femtochemistry | Theory & Computation | Video

Ultrafast Electron Microscopy

UED | UEC | Breaking Boundaries

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.

Selected Publications

Characterization of fast photoelectron packets in weak and strong laser fields in ultrafast electron microscopy, D. A. Plemmons, S. T. Park, A. H. Zewail, D. J. Flannigan, Ultramicroscopy 2014, 146, 97-102.
[Web link] [Abstract] [Top of page]



4D multiple-cathode ultrafast electron microscopy, J. S. Baskin, H. Liu, A. H. Zewail, Proc. Natl. Acad. Sci. USA 2014, 111, 10479-10484.
[Web link] [Abstract] [Top of page]



Observing liquid flow in nanotubes by 4D electron microscopy, U. J. Lorenz, A. H. Zewail, Science 2014, 344, 1496-1500.
[Web link] [Abstract] [Video] [Video] [Top of page]



Photon-induced near-field electron microscopy: Mathematical formulation of the relation between the experimental observables and the optically driven charge density of nanoparticles, S. T. Park, A. H. Zewail, Phys. Rev. A 2014, 89, 013851.
[Web link] [Abstract] [Top of page]



4D imaging and diffraction dynamics of single-particle phase transition in heterogeneous ensembles, H. Liu, O.-H. Kwon, J. Tang, A. H. Zewail, Nano Lett. 2014, 14, 946-954.
[Web link] [Abstract] [Top of page]



Visualization of carrier dynamics in p(n)-type GaAs by scanning ultrafast electron microscopy, J. Cho, T. Y. Hwang, A. H. Zewail, Proc. Natl. Acad. Sci. USA 2014, 111, 2094-2099.
[Web link] [Abstract] [Top of page]



4D cryo-electron microscopy of proteins, A. W. P. Fitzpatrick, U. J. Lorenz, G. M. Vanacore, A. H. Zewail, J. Am. Chem. Soc. 2013, 135, 19123-19126.
[Web link] [Abstract] [Top of page]



Exceptional rigidity and biomechanics of amyloid revealed by 4D electron microscopy, A. W. P. Fitzpatrick, S. T. Park, A. H. Zewail, Proc. Natl. Acad. Sci. USA 2013, 110, 10976-10981.
[Web link] [Abstract] [Video] [Video] [Video] [Top of page]



Graphene-layered steps and their fields visualized by 4D electron microscopy, S. T. Park, A. Yurtsever, J. S. Baskin, A. H. Zewail, Proc. Natl. Acad. Sci. USA 2013, 110, 9277-9282.
[Web link] [Abstract] [Top of page]



Unusual molecular material formed through irreversible transformation and revealed by 4D electron microscopy, R. M. van der Veen, A. Tissot, A. Hauser, A. H. Zewail, Phys. Chem. Chem. Phys. 2013, 15, 7831-7838.
[Web link] [Abstract] [Video] [Video] [Top of page]



Single-nanoparticle phase transitions visualized by 4D electron microscopy, R. M. van der Veen, O.-H. Kwon, A. Tissot, A. Hauser, A. H. Zewail, Nature Chem. 2013, 5, 395-402.
[Web link] [Abstract] [Video] [Top of page]



Biomechanics of DNA structures visualized by 4D electron microscopy, U. J. Lorenz, A. H. Zewail, Proc. Natl. Acad. Sci. USA 2013, 110, 2822-2827.
[Web link] [Abstract] [Video] [Top of page]



Environmental scanning ultrafast electron microscopy: Structural dynamics of solvation at interfaces, D.-S. Yang, O. F. Mohammed, A. H. Zewail, Angew. Chem., Int. Ed. Engl. 2013, 52, 2897-2901.
[Web link] [Abstract] [Top of page]



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]



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]



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]



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]



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]



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]



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]



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]



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]



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]



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]



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]


Earlier Studies