Who I am

I am the principal investigator and an associate staff scientist of the Non-Periodic Imaging task at Stanford PULSE Institute, an independent laboratory of Stanford University and SLAC National Accelerator Laboratory . We lead the effort on X-ray imaging of ultrafast atomic motion and transient structure in molecules, and study the nature of short wavelength strong field interaction with bound and free electrons. My goal is to understand the interplay between correlated electron motion and relaxation, nuclear motion, and photoabsorption in systems that interact with strong fields, and to develop experimental and computational tools to image dynamics at the atomic length and time scales. I received my PhD in Physics from the Weizmann Institute of Science, where I worked with Prof. Yaron Silberberg on coherent control, strong field interaction, nonlinear spectroscopy, and quantum optics.

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Ultrashort CV

Professional Experience:

SLAC National Accelerator Laboratory, Associate Staff Scientist, 2017-today
SLAC National Accelerator Laboratory, Research Associate, 2014-2017
Stanford University, Applied Physics, Postdoctoral fellow, 2011-2014

Education:

Weizmann Institute of Science, PhD Physics, 2009
Weizmann Institute of Science, M.Sc Biological Physics, 2004
Hebrew University, Jerusalem, Israel, B.Sc Physics, 2001

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Research

Imaging coherent dynamics in complex environments

In March 2021 we led the first high-energy (18 keV) ultrafast X-ray scattering experiment in solution aiming to disentangle solute-solvent dynamics at LCLS, and introduced a single shot ultra-wide-angle scattering modality that may dramatically improve the scattering vector range up to 14 Å-1 . The new LCLS capabilities combining high-energy X-rays with extreme brilliance and time resolution can enable us to robustly characterize the non-equilibrium properties of molecules with atomic-scale resolution in time and space and as such present a significant opportunity to advance the discovery of design rules for controlling excited states.

Imaging Strong-Field Induced Motion using High-Order Anisotropy X-ray Scattering

We have presented the first results on ultrafast X-ray scattering of strongly driven molecular systems and analysis of high-order anisotropic components of the scattering signal, up to four-photon absorption. We outlined a method to analyze the scattering signal connecting the high-order anisotropy measured by the detector and the theoretical anisotropy scattering curves. We experimentally observed a multitude of dissociation and vibration motions simultaneously arising from various multiphoton transitions and used the anisotropy information of the scattering signal to disentangle the different processes and assign their dissociation velocities on the Ångström and femtosecond scales de-novo. The approach we demonstrated opens the way to image strong-field-induced motions directly.

Computational analysis methods development

Directly resolving in real-space multiple atomic motions using ultrafast x-ray scattering is generally limited by the finite detector range. As a result, signal interpretation mostly relies on modeling and simulations of specific excitation pathways. We developed a model-free method to carry out real-space inversion and super-resolution of ultrafast x-ray scattering using a scattering signal basis representation that is composed of the experimental measurement parameters and the subsequent signal analysis. We leverage signal priors, such as smoothness and sparsity to deconvolve and super-resolve the spatially transformed signals using convex optimization. We validate the approach on simulated data with detection limits similar to X-ray free-electron laser experiments and described the resolution limits and noise dependence on the accuracy of the recovery.

Energy Resolved Scattering

We are developing methods to resolve and control the bandwidth of x-ray scattering signals, which will be a significant step forward in uncovering electronic motions in photo-excited systems. In July 2021 we have led beamtime in SSRL, collaborating with H. Yavas (LCLS), to characterize the energy resolution and fidelity trade-offs of a novel non-uniformly segmented spherical crystal analyzer that we have designed and fabricated, measuring the bandwidth response as a function of various properties of the analyzer segments, such as their area and aspect ratios.

Singularities in strong-field dissociation

We study two types of singularities in strong field dissociation, the Light-induced conical intersection (LICI), and the cusp-type angular focusing. Conical intersections (CI) are natural degeneracies between Born-Oppenheimer surfaces that facilitate non-radiative energy transfer between electronic states, and play an important role in molecular dynamics. LICIs are degeneracies in the light-induced dressed state basis of the Born-Oppenheimer surfaces. Unlike ordinary CIs, the LICIs can be realized even in diatomic molecules, because the laser polarization adds and additional degree of freedom. We have demonstrated the effect LICI has on the driven diatomic system (H2+), manifested in angular distribution modulations that result from the topological singularity induced by intense laser pulses. A different type of singularity that is under study is a cusp type catastrophe that originating from angular focusing of nonresonant vibration states. When these states are coupled to strong fields, the cusp is observed in angle-resolved H2+ photo-dissociation over a broad kinetic energy release range.

Attosecond dynamics in above-threshold ionization

We have measured the relative phase of different above-threshold ionization (ATI) peaks in a manner that is analogous to the XUV single photon phase measurements that employ RABBITT or the attosecond streak camera. This is multi-path interference of adjacent ATI peaks by a weak probe field at half the frequency. Sideband peaks appear due to absorption or emission of a single probe photon from adjacent ATI levels. We were able to resolve phase delays in ATI as function of the probe field delay to attosecond accuracy. We are expanding these observations to incorporate more detailed angular information, and also to study different regimes of strong-field ionization

Laser induced ultrafast electron diffraction

Laser induced electron diffraction is an evolving tabletop method that aims to image ultrafast structural changes in gas-phase molecules with sub-Ångström spatial and sub-femtosecond temporal resolutions. We are currently developing new experimental and computational methods to extract the self-diffraction signals that contain the information of multiple bond lengths of polyatomic molecules without the need for coincidence type detection.

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Publications

Google Scholar | Academia.edu

Real-Space Inversion and Super-Resolution of Ultrafast X-ray Scattering using Natural Scattering Kernels
A. Natan
arXiv preprint arXiv:2107.05576
Attosecond Coherent Electron Motion in Auger-Meitner Decay
S. Li, et al
arXiv preprint arXiv:2105.08854
Time-resolved diffraction: general discussion
F Allum, K Amini, M Ashfold, D Bansal, RJF Berger, M Centurion, G Dixit, et al
Faraday Discuss. 228, 161-190 (2021)
Time-resolved ultrafast spectroscopy: general discussion
M Ashfold, M Chergui, I Fischer, L Ge, G Grell, M Ivanov, A Kirrander, et al
Faraday Discuss. 228, 329-348 (2021)
Ultrafast X-ray science: general discussion
F Allum, F Calegari, SM Cavaletto, M Centurion, G Dixit, E Fasshauer, et al
Faraday Discuss. 228, 597-621 (2021)
Disentangling the Sub-Cycle Electron Momentum Spectrum in Strong-Field Ionization
N. Werby, A. Natan, R. Forbes, P. H. Bucksbaum
Phys. Rev. Research 3, 023065 (2021)
Resolving Multiphoton Processes with High-Order Anisotropy Ultrafast X-ray Scattering
A. Natan, A. Schori, G. Owolabi, J. P. Cryan, J. M. Glownia, P. H. Bucksbaum
Faraday Discuss. 228, 123-138 (2021)
Electronic population transfer via impulsive stimulated x-ray Raman scattering with attosecond soft-x-ray pulses
J. T. O’Neal, et al
Phys. Rev. Lett. 125 (7) 073203 (2020)
Characterizing multiphoton excitation using time-resolved X-ray scattering
P. H. Bucksbaum, M. R. Ware, A. Natan, J. P. Cryan, J. M. Glownia
Phys. Rev. X 10 (1), 011065 (2020)
X-ray diffractive imaging of controlled gas-phase molecules: Toward imaging of dynamics in the molecular frame
T. Kierspel, A. Morgan, J. Wiese1, T. Mullins, A. Aquila, A. Barty, R. Bean, R. Boll, S. Boutet, P. Bucksbaum, H. N. Chapman, L. Christensen, A. Fry, M. Hunter, J. E. Koglin, M. Liang, V. Mariani, A. Natan, J. Robinson, D. Rolles, A. Rudenko, K. Schnorr, H. Stapelfeldt, S. Stern, J. Thøgersen, C. H. Yoon, F. Wang, and J. Küpper
J. Chem. Phys. 152, 084307, (2020)
Attosecond transient absorption spooktroscopy: a ghost imaging approach to ultrafast absorption spectroscopy
T. Driver, S. Li, , E. G. Champenois, J. Duris, D. Ratner, T. J Lane, P. Rosenberger, A. Al-Haddad, V. Averbukh, T. Barnard, N. Berrah, C. Bostedt, P. H. Bucksbaum, R. Coffee, L. F. DiMauro, L. Fang, D. Garratt, A. Gatton, Z. Guo, G. Hartmann, D. Haxton, W. Helml, Z. Huang, A. LaForge, A. Kamalov, M.F. Kling, J. Knurr, M. Lin, A. A. Lutman, J.P. MacArthur, J. P. Marangos, M. Nantel, A.Natan, R. Obaid, J. T. O'Neal, N. H. Shivaram, A. Schori, P. Walter, A. L. Wang, T.J.A. Wolf, A. Marinelli, and J. P. Cryan
Phys. Chem. Chem. Phys., (2020)
Tunable isolated attosecond X-ray pulses with gigawatt peak power from a free-electron laser
J. Duris, S. Li, T. Driver, E. G. Champenois, J. P. MacArthur, A. A. Lutman, Z. Zhang, P. Rosenberger, J. W. Aldrich, R. Coffee, G. Coslovich, F. Decker, J. M. Glownia, G. Hartmann, W. Helml, A. Kamalov, J. Knurr, J. Krzywinski, M. Lin, J. P. Marangos, M. Nantel, A. Natan, J. T. O’Neal, N. Shivaram, P. Walter, A. L. Wang, J. J. Welch, T. J. A. Wolf, J. Z. Xu, M. F. Kling, P. H. Bucksbaum, A. Zholents, Z. Huang, J. P. Cryan, and A. Marinelli
Nature Photonics 14, 30–36 (2020)
On the limits of observing motion in time-resolved X-ray scattering
M. R. Ware, J. M. Glownia, A. Natan, J. P. Cryan, and P. H. Bucksbaum
Phil. Trans. R. Soc. A . 377, 20170477 (2019)
A co-axial velocity map imaging spectrometer for electrons
S. Li, E. G. Champenois, R. Coffee, Z. Guo, K. Hegazy, A. Kamalov, A. Natan, J. O’Neal1, T. Osipov, M. Owens III, D. Ray, D. Rich, P. Walter, A. Marinelli, and J. P. Cryan
AIP Advances 8, 115308 (2018)
Attosecond time-resolved photoelectron holography
G. Porat, G. Alon, S. Rozen, O. Pedatzur, M. Krüger, D. Azoury, A. Natan, G. Orenstein, B. D. Bruner, M. J. J. Vrakking, and N. Dudovich
Nature Communications 9, 2805 (2018).
Characterizing isolated attosecond pulses with angular streaking
S. Li, Z. Guo, R. N. Coffee, K. Hegazy, Z. Huang, A. Natan, T. Osipov, D. Ray, A. Marinelli, and J. P. Cryan
Optics Express 26, Issue 4, 4531-4547 (2018)
Imaging the Breakdown of Molecular Frame Dynamics through Rotational Uncoupling
L. J. Zipp, A. Natan, and P. H. Bucksbaum
Phys. Rev. A 95, 061403(R) (2017)
Probing ultrafast ππ*/nπ* internal conversion in organic chromophores via K-edge resonant absorption
T.J.A. Wolf, R.H. Myhre, J.P. Cryan, S. Coriani, R.J. Squibb, A. Battistoni, N. Berrah, C. Bostedt, P. Bucksbaum, G. Coslovich, R. Feifel, K.J. Gaffney, J. Grilj, T.J. Martinez, S. Miyabe, S.P. Moeller, M. Mucke, A. Natan, R. Obaid, T. Osipov, O. Plekan, S. Wang, H. Koch, M. Gühr
Nature Communications 8, 29 (2017).
Self-referenced coherent diffraction x-ray movie of Angstrom-and femtosecond-scale atomic motion
J.M. Glownia*, A. Natan*, J.P. Cryan, R. Hartsock, M. Kozina, M.P. Minitti, S. Nelson, J. Robinson, T. Sato, T. van Driel, G. Welch, C. Weninger, D. Zhi, P.H. Bucksbaum, (*equally contributed)
Phys. Rev. Lett. 117 153003 (2016)
Observation of Quantum Interferences via Light-Induced Conical Intersections in Diatomic Molecules
A. Natan, M.R. Ware, V. S. Prabhudesai, U. Lev, B.D. Bruner, O. Heber, P.H. Bucksbaum
Phys. Rev. Lett. 116 143004 (2016)
Auger electron and photoabsorption spectra of glycine in the vicinity of the oxygen K-edge measured with an X-FEL
A. Sanchez-Gonzalez, T. R. Barillot, R. J. Squibb, P. Kolorenč, M. Agaker, V. Averbukh, M. J. Bearpark, C. Bostedt, J. D. Bozek, S. Bruce, S. Carron Montero, R. N. Coffee, B. Cooper, J. P. Cryan, M. Dong, J. H. D. Eland, L. Fang, H. Fukuzawa, M. Guehr, M. Ilchen, A. S. Johnsson, C. Liekhus-S, A. Marinelli, T. Maxwel, K. Motomura, M. Mucke, A. Natan, T. Osipov, C. Östlin, M. Pernpointner, V. S. Petrovic, M. A. Robb, C. Sathe, E. R. Simpson, J. G. Underwood, M. Vacher, D. J. Walke, T. J. A. Wolf, V. Zhaunerchyk, J-E Rubensson, N. Berrah, P. H. Bucksbaum, K. Ueda, R. Feifel, L. J. Frasinski and J. P. Marangos.
J. Phys. B. 48 (23), 234004 (2015)
Strongly aligned gas-phase molecules at free-electron lasers
T. Kierspel, J. Wiese, T. Mullins, J. Robinson, A. Aquila, A. Barty, R. Bean, R. Boll, S. Boutet, P. Bucksbaum, H. N. Chapman, L. Christensen, A. Fry, M. Hunter, J. E. Koglin, M. Liang, V. Mariani, A. Morgan, A. Natan, V. Petrovic, D. Rolles, A. Rudenko, K. Schnorr, H. Stapelfeldt, S. Stern, J. Thøgersen, C. Hong Yoon, F. Wang, S. Trippel, J. Küpper
J. Phys. B. 48 (20), 204002 (2015)
Ultrafast Isomerization Initiated by X-Ray Core Ionization
C. E. Liekhus-Schmaltz, I. Tenney, T. Osipov, A. Sanchez, A. Belkacem, N. Berrah, R. Boll, C. Bomme, C. Bostedt, J. D. Bozek, S. Carron, R. Coffee, J. Devin, B. Erk, L. Fang, K. Ferguson, R. W. Field, L. Foucar, L. Frasinski, J. M. Glownia, M. Gühr, A. Kamalov, J. Krzywinski, H. Li, J. P. Marangos, T. Martinez, B. K. McFarland, S. Miyabe, B. Murphy, A. Natan, D. Rolles, A. Rudenko, M. Siano, E. Simpson, L. Spector, M. Swiggers, D. Walke, S. Wang, T. Webber, P. H. Bucksbaum, and V. S. Petrovic
Nature Communications 6 , 8199 (2015).
Quantum control of photodissociation using intense, femtosecond pulses shaped with third order dispersion
U. Lev, L. Graham, C.B. Madsen, I. Ben-Itzhak, B.D. Bruner, B.D. Esry, H. Frostig, O. Heber, A. Natan, V.S. Prabhudesai, D. Schwalm, Y. Silberberg, D. Strasser, I.D. Williams, D. Zajfman
J. Phys. B. 48 (20), 201001 (2015)
Probing electron delays in above threshold ionization
L. J. Zipp, A. Natan, and P. H. Bucksbaum
Optica, 1 (6), 361-364 (2014)
Delayed Delayed Ultrafast X-ray Auger Probing (DUXAP) of Nucleobase Ultraviolet Photoprotection
B. McFarland, J. Farrell, N. Berrah, C. Bostedt, J. Bozek, P. H. Bucksbaum, R. Coffee, J. Cryan, L. Fang, R. Feifel, K. Gaffney, J. M. Glownia, T. Martinez, M. Mucke, B. Murphy, S. Miyabe, A. Natan, T. Osipov, V. Petrovic, S. Schorb, T. Schultz, L. Spector, F. Tarantelli, I. Tenney, S. Wang, W. White, J. White, and M. Guehr
Nature Communications 5 (2014)
Quantum control of photodissociation by manipulation of bond softening
A. Natan, V. S. Prabhudesai, U. Lev, B. D. Bruner, D. Strasser, D. Schwalm, I. Ben-Itzhak, O. Heber, D. Zajfman, and Y. Silberberg
Phys. Rev. A. 86, 043418 (2012)
Standoff detection via single-beam spectral notch filtered pulses
A. Natan, J. M. Levitt, L. Graham, O. Katz, and Y. Silberberg.
Appl. Phys. Lett. 100, 051111 (2012)
Effect of Linear Chirp on Strong Field Photodissociation of H2+
V. S. Prabhudesai, A. Natan, B. D. Bruner, Y. Silberberg, U. Lev, O. Heber, D. Strasser, D. Schwalm, D. Zajfman, I. Ben-Itzhak.
J. Korean Phys. Soc. 59 , 2890 (2011)
Single-pulse stimulated Raman scattering spectroscopy
H. Frostig, O. Katz, A. Natan, and Y. Silberberg.
Optics Letters, 36 (7), 1248 (2011)
Tracing the photodissociation probability of H2+ in intense fields using chirped laser pulses
V. S. Prabhudesai, U. Lev, A. Natan, B. D. Bruner, A. Diner, O. Heber, D. Strasser, D. Schwalm, I. Ben-Itzhak, J. J. Hua, B. D. Esry, Y. Silberberg, and D. Zajfman
Phys. Rev. A 81 023401 (2010)
Quantum state measurements using multipixel photon detectors
I. Afek, A. Natan, O. Ambar, and Y. Silberberg
Phys. Rev. A 79, 043830 (2009)
Shaped Femtosecond Pulses for Remote Chemical Detection
O. Katz, A. Natan, S. Rosenwaks, and Y. Silberberg
Opt. Phot. News 47 , Dec (2008)
Standoff detection of trace amounts of solids by nonlinear Raman spectroscopy using shaped femtosecond pulses
O. Katz, A. Natan, Y. Silberberg, and S. Rosenwaks
Appl. Phys. Lett. 92, 171116 (2008)
Spatio-temporal coherent control of atomic systems: weak to strong field transition and breaking of symmetry in 2D maps
H. Suchowski, A. Natan, B.D Bruner and Y. Silberberg
J. Phys. B. 41 074008 (2008)

 

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Codes

"A man must have a code." (Bunk Moreland)

GitHub | Matlab File Exchange

2D Fast Peak Finder The aim was to be faster than more sophisticated techniques yet good enough to find peaks in noisy data. The code analyzes noisy 2D images and find peaks using robust local maxima finder (1 pixel resolution) or by weighted centroids (sub-pixel resolution). The code is designed to be as fast as possible, so I kept it pretty basic. It best works when using uint16 or uint8 images, and assumes that peaks are relatively sparse. download.


Polar Onion Peeling (POP) is a fast method that combines onion peeling in the radial axis with Legedre decomposition in the angle axis, to deconvolve raw velocity map imaging data. The code implements the method shown at Rev. Sci. Instr. 80, 053104 (2009). It supports images of up to 4K resolution and accepts arbitrary (even) beta parameters. Specific quadrants of the image can be selected in the analysis in case of image asymmetries. download.


Beam propagation This code simulates the focusing of spherical Gaussian beams using a series of thin lenses (Based on Applied Optics, Vol. 22, Issue 5, pp. 658-661 (1983). download.


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