A5059687673- Laser-Matter Interactions and Applications
- Spectroscopy and Quantum Chemical Studies
- Mass Spectrometry Techniques and Applications
- Advanced Chemical Physics Studies
- Advanced Fiber Laser Technologies
- Topological Materials and Phenomena
- Terahertz technology and applications
- 2D Materials and Applications
- Physics of Superconductivity and Magnetism
- Iron-based superconductors research
- Quantum, superfluid, helium dynamics
- Rare-earth and actinide compounds
- Spectroscopy and Laser Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Inorganic Chemistry and Materials
- Advanced Condensed Matter Physics
- Phase-change materials and chalcogenides
- Quantum Information and Cryptography
- Laser Design and Applications
- Quantum many-body systems
- Photocathodes and Microchannel Plates
- Machine Learning in Materials Science
- Diatoms and Algae Research
- Quantum optics and atomic interactions
- CCD and CMOS Imaging Sensors
Tel Aviv University
2020-2025
SLAC National Accelerator Laboratory
2015-2021
Weizmann Institute of Science
2010-2020
Stanford University
2017
Technion – Israel Institute of Technology
2014
A deeper look into iron selenide In the past 10 years, iron-based superconductors have created more puzzles than they helped resolve. Some of most fundamental outstanding questions are how strong interactions and what electron pairing mechanism is. Now two groups made contributions toward resolving these in intriguing compound (FeSe) (see Perspective by Lee). Gerber et al. used photoemission spectroscopy coupled with x-ray diffraction to find that FeSe has a very sizable electron-phonon...
We report the observation of an anomalous nonlinear optical response prototypical three-dimensional topological insulator bismuth selenide through process high-order harmonic generation. find that generation efficiency increases as laser polarization is changed from linear to elliptical, and it becomes maximum for circular polarization. With aid a microscopic theory detailed analysis measured spectra, we reveal such enhancement encodes characteristic topology band structure originates...
In the past decade, topological materials have been continuously attracting interest of condensed-matter physics community because their unique band structures and transport properties. Recently, ZrTe${}_{5}$ is becoming a promising platform to study phase transitions, as it could possibly be 3D Dirac semimetal, weak insulator (TI), or strong TI, which are distinguished by whether there finite gap surface state (TSS). This paper performs systematic high-momentum-resolution photoemission on...
Abstract High-order harmonic generation in polyatomic molecules generally involves multiple channels of ionization. Their relative contribution can be strongly influenced by the presence resonances, whose assignment remains a major challenge for high-harmonic spectroscopy. Here we present multi-modal approach investigation unaligned molecules, using SF 6 as an example. We combine methods from extreme-ultraviolet spectroscopy, above-threshold ionization and attosecond metrology....
We study the microscopic origins of photocurrent generation in topological insulator Bi$_2$Se$_3$ via time- and angle-resolved photoemission spectroscopy. image unoccupied band structure as it evolves following a circularly polarized optical excitation observe an asymmetric electron population momentum space, which is spectroscopic signature photocurrent. By analyzing rise times we identify occupied electronic states are coupled by excitation. conclude that photocurrents can only be excited...
We study high-order harmonic generation in aligned molecules close to the ionization threshold. Two distinct contributions signal are observed, which show very different responses molecular alignment and ellipticity of driving field. perform a classical electron trajectory analysis, taking into account significant influence Coulomb potential on strong-field-driven dynamics. The two related primary excitation processes, offering deeper understanding origin high harmonics near This Letter...
In strong-field light-matter interactions, the strong laser field dominates dynamics. However, recent experiments indicate that Coulomb force can play an important role as well. this Letter, we have studied photoelectron momentum distributions produced from noble gases in elliptically polarized, 800 nm light. By performing a complete mapping of three-dimensional electron momentum, find focusing significantly narrows lateral spread. We surprisingly sensitive dependence on initial transverse...
We investigated the giant resonance in xenon by high-order harmonic generation spectroscopy driven a two-color field. The addition of nonperturbative second component parallel to driving field breaks symmetry between neighboring subcycles resulting appearance spectral caustics at two distinct cutoff energies. By controlling phase delay color components it is possible tailor emission order amplify and isolate feature interest. In this Letter we demonstrate how control scheme can be used...
High harmonic generation (HHG) spectroscopy has opened up a new frontier in ultrafast science, where electronic dynamics can be measured on an attosecond time scale. The strong laser field that triggers the high response also opens multiple quantum pathways for multielectron molecules, resulting complex process of rearrangement during ionization. Using combined experimental and theoretical approaches, we show how multi-dimensional HHG used to detect follow core sub-laser cycle scales. We...
Oscillatory signals from coherently excited phonons are regularly observed in ultrafast pump–probe experiments on condensed matter samples. Electron–phonon coupling implies that coherent also modulate the electronic band structure. These oscillations can be probed with energy and momentum resolution using time- angle-resolved photoemission spectroscopy (trARPES), which reveals orbital dependence of electron–phonon for a specific phonon mode. However, comprehensive analysis remains...
Cuprate superconductors host a multitude of low-energy optical phonons. Using time- and angle-resolved photoemission spectroscopy, we study coherent phonons in Bi_{2}Sr_{2}Ca_{0.92}Y_{0.08}Cu_{2}O_{8+δ}. Sub-meV modulations the electronic band structure are observed at frequencies 3.94±0.01 5.59±0.06 THz. For dominant mode 3.94 THz, amplitude energy oscillation weakly increases as function momentum away from node. Theoretical calculations allow identifying modes CuO_{2}-derived A_{1g} The...
Recollision processes provide direct insight into the structure and dynamics of electronic wave functions. However, strength process sets its basic limitations---the interaction couples numerous degrees freedom. In this Letter we decouple steps resolve role ionic potential which is at heart a broad range strong field phenomena. Specifically, measure high harmonic generation from argon atoms. By manipulating polarization laser vectorial properties interaction. Our study shows that core plays...
High harmonic generation (HHG) has opened up a new frontier in ultrafast science where attosecond time resolution and Angstrom spatial are accessible single measurement. However, reconstructing the dynamics under study is limited by multiple degrees of freedom involved strong field interactions. In this paper we describe class measurement schemes for resolving dynamics, integrating perturbative nonlinear optics with strong-field physics. These approaches serve as basis multidimensional high...
We study optimally doped ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{Ca}}_{0.92}{\mathrm{Y}}_{0.08}{\mathrm{Cu}}_{2}{\mathrm{O}}_{8+\ensuremath{\delta}}$ (Bi2212) using angle-resolved two-photon photoemission spectroscopy. Three spectral features are resolved near 1.5, 2.7, and 3.6 eV above the Fermi level. By tuning photon energy, we determine that 2.7-eV feature arises predominantly from unoccupied states. The 1.5- 3.6-eV reflect states whose intensities strongly modulated by corresponding...
In photoelectron spectroscopy, the measured electron momentum range is intrinsically related to excitation photon energy. Low energies <10 eV are commonly encountered in laser-based photoemission and lead a that smaller than Brillouin zones of most materials. This can become limiting factor when studying condensed matter with photoemission. An additional restriction introduced by widely used hemispherical analyzers record only electrons photoemitted solid angle set aperture size at analyzer...
Strong field transient grating spectroscopy has shown to be a very versatile tool in time-resolved molecular spectroscopy. Here we use this technique investigate the high-order harmonic generation from SF6 molecules vibrationally excited by impulsive stimulated Raman scattering. Transient enables us reveal clear modulations of emission. This heterodyne detection shows that emission generated between 14 26 eV is mainly sensitive two among three active modes SF6, i.e. strongest and fully...
Probing electronic wave functions of polyatomic molecules is one the major challenges in high-harmonic spectroscopy. The extremely nonlinear nature laser-molecule interaction couples multiple degrees freedom probed system. We combine two-dimensional control electron trajectories and vibrational to disentangle two main steps generation-ionization recombination. introduce a new measurement scheme, frequency-resolved optomolecular gating, which resolves temporal amplitude phase harmonic...
Spectral focusing of the recolliding electron in high-order harmonic generation driven by two-color fields is shown to be a powerful tool for isolating and enhancing hidden spectral features target under study. In previous works we used this technique probing multi-electron effects xenon compared our experimental results with time-dependent configuration-interaction singles calculations. We demonstrate here that can exploited reconstructing enhancement factor giant dipole resonance discuss...
High-harmonics generation spectroscopy is a promising tool for resolving electron dynamics and structure in atomic molecular systems.This scheme, commonly described by the strong field approximation, requires deep insight into basic mechanism that leads to harmonics generation.Recently, we have demonstrated ability resolve first stage of process -field induced tunnel ionization -by adding weak perturbation fundamental field.Here generalize this approach show assumptions behind approximation...
We determine the work functions of iron arsenic compounds $A$Fe$_2$As$_2$ ($A=\mathrm{Ca, Ba, Cs}$) using photoemission spectroscopy to be 2.7 eV for CaFe$_2$As$_2$, 1.8 BaFe$_2$As$_2$, and 1.3 CsFe$_2$As$_2$. The these 122 iron-based superconductors track those elementary metal $A$ but are substantially smaller. most likely explanation this observation is that cleaving surface exposes only half an $A$-layer. low function good cross section BaFe$_2$As$_2$ CsFe$_2$As$_2$ enable even from a...
The vast potential applications of biomolecules that bind inorganic surfaces led mostly to the isolation short peptides target selectively specific materials. demonstrated differential affinity toward certain created impression recognition capacity may match rigid biomolecules. In following, we challenge this view by comparing antibody molecules discriminate between (100) and (111A) facets a gallium arsenide semiconductor crystal with do same. Applying selection from several peptide single...