keyword
MENU ▼
Read by QxMD icon Read
search

attosecond

keyword
https://www.readbyqxmd.com/read/28729510/tailored-semiconductors-for-high-harmonic-optoelectronics
#1
Murat Sivis, Marco Taucer, Giulio Vampa, Kyle Johnston, André Staudte, Andrei Yu Naumov, D M Villeneuve, Claus Ropers, P B Corkum
The advent of high-harmonic generation in gases 30 years ago set the foundation for attosecond science and facilitated ultrafast spectroscopy in atoms, molecules, and solids. We explore high-harmonic generation in the solid state by means of nanostructured and ion-implanted semiconductors. We use wavelength-selective microscopic imaging to map enhanced harmonic emission and show that the generation medium and the driving field can be locally tailored in solids by modifying the chemical composition and morphology...
July 21, 2017: Science
https://www.readbyqxmd.com/read/28714468/high-order-harmonic-generation-from-the-dressed-autoionizing-states
#2
M A Fareed, V V Strelkov, N Thiré, S Mondal, B E Schmidt, F Légaré, T Ozaki
In high-order harmonic generation, resonant harmonics (RH) are sources of intense, coherent extreme-ultraviolet radiation. However, intensity enhancement of RH only occurs for a single harmonic order, making it challenging to generate short attosecond pulses. Moreover, the mechanism involved behind such RH was circumstantial, because of the lack of direct experimental proofs. Here, we demonstrate the exact quantum paths that electron follows for RH generation using tin, showing that it involves not only the autoionizing state, but also a harmonic generation from dressed-AIS that appears as two coherent satellite harmonics at frequencies ±2Ω from the RH (Ω represents laser frequency)...
July 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/28706325/axsis-exploring-the-frontiers-in-attosecond-x-ray-science-imaging-and-spectroscopy
#3
F X Kärtner, F Ahr, A-L Calendron, H Çankaya, S Carbajo, G Chang, G Cirmi, K Dörner, U Dorda, A Fallahi, A Hartin, M Hemmer, R Hobbs, Y Hua, W R Huang, R Letrun, N Matlis, V Mazalova, O D Mücke, E Nanni, W Putnam, K Ravi, F Reichert, I Sarrou, X Wu, A Yahaghi, H Ye, L Zapata, D Zhang, C Zhou, R J D Miller, K K Berggren, H Graafsma, A Meents, R W Assmann, H N Chapman, P Fromme
X-ray crystallography is one of the main methods to determine atomic-resolution 3D images of the whole spectrum of molecules ranging from small inorganic clusters to large protein complexes consisting of hundred-thousands of atoms that constitute the macromolecular machinery of life. Life is not static, and unravelling the structure and dynamics of the most important reactions in chemistry and biology is essential to uncover their mechanism. Many of these reactions, including photosynthesis which drives our biosphere, are light induced and occur on ultrafast timescales...
September 1, 2016: Nuclear Instruments & Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment
https://www.readbyqxmd.com/read/28701692/next-generation-driver-for-attosecond-and-laser-plasma-physics
#4
D E Rivas, A Borot, D E Cardenas, G Marcus, X Gu, D Herrmann, J Xu, J Tan, D Kormin, G Ma, W Dallari, G D Tsakiris, I B Földes, S-W Chou, M Weidman, B Bergues, T Wittmann, H Schröder, P Tzallas, D Charalambidis, O Razskazovskaya, V Pervak, F Krausz, L Veisz
The observation and manipulation of electron dynamics in matter call for attosecond light pulses, routinely available from high-order harmonic generation driven by few-femtosecond lasers. However, the energy limitation of these lasers supports only weak sources and correspondingly linear attosecond studies. Here we report on an optical parametric synthesizer designed for nonlinear attosecond optics and relativistic laser-plasma physics. This synthesizer uniquely combines ultra-relativistic focused intensities of about 10(20) W/cm(2) with a pulse duration of sub-two carrier-wave cycles...
July 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28657621/ultrafast-dynamics-in-the-dna-building-blocks-thymidine-and-thymine-initiated-by-ionizing-radiation
#5
E P Månsson, S De Camillis, M C Castrovilli, M Galli, M Nisoli, F Calegari, J B Greenwood
Understanding how energetic charged particles damage DNA is crucial for improving radiotherapy techniques such as hadron therapy and for the development of new radiosensitizer drugs. In the present study, the damage caused by energetic particles was simulated by measuring the action of extreme ultraviolet (XUV) attosecond pulses on the DNA building blocks thymine and thymidine. This allowed the ultrafast processes triggered by direct ionization to be probed with an optical pulse with a time resolution of a few femtoseconds...
June 28, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28643771/dynamics-of-valence-shell-electrons-and-nuclei-probed-by-strong-field-holography-and-rescattering
#6
Samuel G Walt, Niraghatam Bhargava Ram, Marcos Atala, Nikolay I Shvetsov-Shilovski, Aaron von Conta, Denitsa Baykusheva, Manfred Lein, Hans Jakob Wörner
Strong-field photoelectron holography and laser-induced electron diffraction (LIED) are two powerful emerging methods for probing the ultrafast dynamics of molecules. However, both of them have remained restricted to static systems and to nuclear dynamics induced by strong-field ionization. Here we extend these promising methods to image purely electronic valence-shell dynamics in molecules using photoelectron holography. In the same experiment, we use LIED and photoelectron holography simultaneously, to observe coupled electronic-rotational dynamics taking place on similar timescales...
June 15, 2017: Nature Communications
https://www.readbyqxmd.com/read/28636679/towards-the-analysis-of-attosecond-dynamics-in-complex-systems
#7
C-Z Gao, P M Dinh, P-G Reinhard, E Suraud
We study from a theoretical perspective the ionization of molecules and clusters induced by irradiation of a combined two-color laser field consisting of a train of attosecond XUV pulses in the presence of an IR field. We use time-dependent density-functional theory (TDDFT) in real time and real space as a theoretical tool. The calculated results are compared to experimental data when available. We also compare TDDFT with results obtained using a time-dependent Schrödinger equation (TDSE), which is well suited to simple systems while TDDFT allows dealing with more complex molecules and clusters...
June 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28631783/ultrafast-charge-dynamics-in-glycine-induced-by-attosecond-pulses
#8
David Ayuso, Alicia Palacios, Piero Decleva, Fernando Martín
The combination of attosecond pump-probe techniques with mass spectrometry methods has recently led to the first experimental demonstration of ultrafast charge dynamics in a biomolecule, the amino acid phenylalanine [Calegari et al., Science, 2014, 346, 336]. Using an extension of the static-exchange density functional theory (DFT) method, the observed dynamics was explained as resulting from the coherent superposition of ionic states produced by the broadband attosecond pulse. Here, we have used the static-exchange DFT method to investigate charge migration induced by attosecond pulses in the glycine molecule...
June 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28630331/distinguishing-attosecond-electron-electron-scattering-and-screening-in-transition-metals
#9
Cong Chen, Zhensheng Tao, Adra Carr, Piotr Matyba, Tibor Szilvási, Sebastian Emmerich, Martin Piecuch, Mark Keller, Dmitriy Zusin, Steffen Eich, Markus Rollinger, Wenjing You, Stefan Mathias, Uwe Thumm, Manos Mavrikakis, Martin Aeschlimann, Peter M Oppeneer, Henry Kapteyn, Margaret Murnane
Electron-electron interactions are the fastest processes in materials, occurring on femtosecond to attosecond timescales, depending on the electronic band structure of the material and the excitation energy. Such interactions can play a dominant role in light-induced processes such as nano-enhanced plasmonics and catalysis, light harvesting, or phase transitions. However, to date it has not been possible to experimentally distinguish fundamental electron interactions such as scattering and screening. Here, we use sequences of attosecond pulses to directly measure electron-electron interactions in different bands of different materials with both simple and complex Fermi surfaces...
July 3, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28619939/coherent-imaging-of-an-attosecond-electron-wave-packet
#10
D M Villeneuve, Paul Hockett, M J J Vrakking, Hiromichi Niikura
Electrons detached from atoms or molecules by photoionization carry information about the quantum state from which they originate, as well as the continuum states into which they are released. Generally, the photoelectron momentum distribution is composed of a coherent sum of angular momentum components, each with an amplitude and phase. Here we show, by using photoionization of neon, that a train of attosecond pulses synchronized with an infrared laser field can be used to disentangle these angular momentum components...
June 16, 2017: Science
https://www.readbyqxmd.com/read/28618496/plasma-high-order-harmonic-generation-from-ultraintense-laser-pulses
#11
Suo Tang, Naveen Kumar, Christoph H Keitel
Plasma high-order-harmonic generation from an extremely intense short-pulse laser is explored by including the effects of ion motion, electron-ion collisions, and radiation reaction force in the plasma dynamics. The laser radiation pressure induces plasma ion motion through the hole-boring effect, resulting in frequency shifting and widening of the harmonic spectra. The classical radiation reaction force slightly mitigates the frequency broadening caused by the ion motion. Based on the results and physical considerations, parameter maps highlighting the optimum regions for generating a single intense attosecond pulse and coherent XUV radiation are presented...
May 2017: Physical Review. E
https://www.readbyqxmd.com/read/28597901/a-perspective-for-investigating-photo-induced-molecular-dynamics-from-within-with-femtosecond-free-electron-lasers
#12
Nora Berrah
Photo-induced molecular dynamics can now be investigated using free electron lasers (FELs) whose attributes are unprecedented brightness, few femtosecond pulses duration and in the near future few hundreds of attosecond pulse duration. These relatively new tools are utilized to investigate photon-induced physical and chemical processes by ionizing inner-shell electrons and thus unlocking molecular dynamics from within.
June 9, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28572835/symmetry-controlled-time-structure-of-high-harmonic-carrier-fields-from-a-solid
#13
F Langer, M Hohenleutner, U Huttner, S W Koch, M Kira, R Huber
High-harmonic (HH) generation in crystalline solids1-6 marks an exciting development, with potential applications in high-efficiency attosecond sources7, all-optical bandstructure reconstruction8,9, and quasiparticle collisions10,11. Although the spectral1-4 and temporal shape5 of the HH intensity has been described microscopically1-6,12, the properties of the underlying HH carrier wave have remained elusive. Here we analyse the train of HH waveforms generated in a crystalline solid by consecutive half cycles of the same driving pulse...
April 2017: Nature Photonics
https://www.readbyqxmd.com/read/28555640/attosecond-interferometry-with-self-amplified-spontaneous-emission-of-a-free-electron-laser
#14
Sergey Usenko, Andreas Przystawik, Markus Alexander Jakob, Leslie Lamberto Lazzarino, Günter Brenner, Sven Toleikis, Christian Haunhorst, Detlef Kip, Tim Laarmann
Light-phase-sensitive techniques, such as coherent multidimensional spectroscopy, are well-established in a broad spectral range, already spanning from radio-frequencies in nuclear magnetic resonance spectroscopy to visible and ultraviolet wavelengths in nonlinear optics with table-top lasers. In these cases, the ability to tailor the phases of electromagnetic waves with high precision is essential. Here we achieve phase control of extreme-ultraviolet pulses from a free-electron laser (FEL) on the attosecond timescale in a Michelson-type all-reflective interferometric autocorrelator...
May 30, 2017: Nature Communications
https://www.readbyqxmd.com/read/28524203/time-resolved-photoelectron-spectroscopy-of-ir-driven-electron-dynamics-in-a-charge-transfer-model-system
#15
Mirjam Falge, Friedrich Georg Fröbel, Volker Engel, Stefanie Gräfe
If the adiabatic approximation is valid, electrons smoothly adapt to molecular geometry changes. In contrast, as a characteristic of diabatic dynamics, the electron density does not follow the nuclear motion. Recently, we have shown that the asymmetry in time-resolved photoelectron spectra serves as a tool to distinguish between these dynamics [Falge et al., J. Phys. Chem. Lett., 2012, 3, 2617]. Here, we investigate the influence of an additional, moderately intense infrared (IR) laser field, as often applied in attosecond time-resolved experiments, on such asymmetries...
May 19, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28488433/attosecond-electron-dynamics-in-molecules
#16
Mauro Nisoli, Piero Decleva, Francesca Calegari, Alicia Palacios, Fernando Martín
Advances in attosecond science have led to a wealth of important discoveries in atomic, molecular, and solid-state physics and are progressively directing their footsteps toward problems of chemical interest. Relevant technical achievements in the generation and application of extreme-ultraviolet subfemtosecond pulses, the introduction of experimental techniques able to follow in time the electron dynamics in quantum systems, and the development of sophisticated theoretical methods for the interpretation of the outcomes of such experiments have raised a continuous growing interest in attosecond phenomena, as demonstrated by the vast literature on the subject...
May 10, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28468499/attosecond-dynamics-of-molecular-electronic-ring-currents
#17
Kai-Jun Yuan, Chuan-Cun Shu, Daoyi Dong, André D Bandrauk
Ultrafast charge migration is of fundamental importance to photoinduced chemical reactions. However, exploring such a quantum dynamical process requires demanding spatial and temporal resolutions. We show how electronic coherence dynamics induced in molecules by a circularly polarized UV pulse can be tracked by using a time-delayed circularly polarized attosecond X-ray pulse. The X-ray probe spectra retrieve an image at different time delays, encoding instantaneous pump-induced circular charge migration information on an attosecond time scale...
May 5, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28463649/extending-quantum-chemistry-of-bound-states-to-electronic-resonances
#18
Thomas-C Jagau, Ksenia B Bravaya, Anna I Krylov
Electronic resonances are metastable states with finite lifetime embedded in the ionization or detachment continuum. They are ubiquitous in chemistry, physics, and biology. Resonances play a central role in processes as diverse as DNA radiolysis, plasmonic catalysis, and attosecond spectroscopy. This review describes novel equation-of-motion coupled-cluster (EOM-CC) methods designed to treat resonances and bound states on an equal footing. Built on complex-variable techniques such as complex scaling and complex absorbing potentials that allow resonances to be associated with a single eigenstate of the molecular Hamiltonian rather than several continuum eigenstates, these methods extend electronic-structure tools developed for bound states to electronic resonances...
May 5, 2017: Annual Review of Physical Chemistry
https://www.readbyqxmd.com/read/28454168/laser-waveform-control-of-extreme-ultraviolet-high-harmonics-from-solids
#19
Yong Sing You, Mengxi Wu, Yanchun Yin, Andrew Chew, Xiaoming Ren, Shima Gholam-Mirzaei, Dana A Browne, Michael Chini, Zenghu Chang, Kenneth J Schafer, Mette B Gaarde, Shambhu Ghimire
Solid-state high-harmonic sources offer the possibility of compact, high-repetition-rate attosecond light emitters. However, the time structure of high harmonics must be characterized at the sub-cycle level. We use strong two-cycle laser pulses to directly control the time-dependent nonlinear current in single-crystal MgO, leading to the generation of extreme ultraviolet harmonics. We find that harmonics are delayed with respect to each other, yielding an atto-chirp, the value of which depends on the laser field strength...
May 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28430519/energy-resolved-ultrashort-delays-of-photoelectron-emission-clocked-by-orthogonal-two-color-laser-fields
#20
Xiaochun Gong, Cheng Lin, Feng He, Qiying Song, Kang Lin, Qinying Ji, Wenbin Zhang, Junyang Ma, Peifen Lu, Yunquan Liu, Heping Zeng, Weifeng Yang, Jian Wu
A phase-controlled orthogonal two-color (OTC) femtosecond laser pulse is employed to probe the time delay of photoelectron emission in the strong-field ionization of atoms. The OTC field spatiotemporally steers the emission dynamics of the photoelectrons and meanwhile allows us to unambiguously distinguish the main and sideband peaks of the above-threshold ionization spectrum. The relative phase shift between the main and sideband peaks, retrieved from the phase-of-phase of the photoelectron spectrum as a function of the laser phase, gradually decreases with increasing electron energy, and becomes zero for the fast electron which is mainly produced by the rescattering process...
April 7, 2017: Physical Review Letters
keyword
keyword
83153
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"