Attoscience and ultrafast opticshttp://hdl.handle.net/2117/237582024-03-28T12:54:35Z2024-03-28T12:54:35ZLaser-induced electron diffraction of the ultrafast umbrella motion in ammoniaBelsa, B.Amini, K.Liu, X.Sánchez, A.Steinle, T.Steinmetzer, J.Le, A. T.Moshammer, R.Pfeifer, T.Ullrich, J.Moszynski, R.Lin, C. D.Grafe, S.Biegert, Jenshttp://hdl.handle.net/2117/3504742022-10-13T09:41:22Z2021-08-17T08:48:46ZLaser-induced electron diffraction of the ultrafast umbrella motion in ammonia
Belsa, B.; Amini, K.; Liu, X.; Sánchez, A.; Steinle, T.; Steinmetzer, J.; Le, A. T.; Moshammer, R.; Pfeifer, T.; Ullrich, J.; Moszynski, R.; Lin, C. D.; Grafe, S.; Biegert, Jens
Visualizing molecular transformations in real-time requires a structural retrieval method with Ångström spatial and femtosecond temporal atomic resolution. Imaging of hydrogen-containing molecules additionally requires an imaging method sensitive to the atomic positions of hydrogen nuclei, with most methods possessing relatively low sensitivity to hydrogen scattering. Laser-induced electron diffraction (LIED) is a table-top technique that can image ultrafast structural changes of gas-phase polyatomic molecules with sub-Ångström and femtosecond spatiotemporal resolution together with relatively high sensitivity to hydrogen scattering. Here, we image the umbrella motion of an isolated ammonia molecule (NH3) following its strong-field ionization. Upon ionization of a neutral ammonia molecule, the ammonia cation (NH3+) undergoes an ultrafast geometrical transformation from a pyramidal (𝛷����������HNH=107°) to planar (𝛷����������HNH=120°) structure in approximately 8 femtoseconds. Using LIED, we retrieve a near-planar (𝛷����������HNH=117 ± 5°) field-dressed NH3+ molecular structure 7.8−9.8 femtoseconds after ionization. Our measured field-dressed NH3+ structure is in excellent agreement with our calculated equilibrium field-dressed structure using quantum chemical ab initio calculations.
2021-08-17T08:48:46ZBelsa, B.Amini, K.Liu, X.Sánchez, A.Steinle, T.Steinmetzer, J.Le, A. T.Moshammer, R.Pfeifer, T.Ullrich, J.Moszynski, R.Lin, C. D.Grafe, S.Biegert, JensVisualizing molecular transformations in real-time requires a structural retrieval method with Ångström spatial and femtosecond temporal atomic resolution. Imaging of hydrogen-containing molecules additionally requires an imaging method sensitive to the atomic positions of hydrogen nuclei, with most methods possessing relatively low sensitivity to hydrogen scattering. Laser-induced electron diffraction (LIED) is a table-top technique that can image ultrafast structural changes of gas-phase polyatomic molecules with sub-Ångström and femtosecond spatiotemporal resolution together with relatively high sensitivity to hydrogen scattering. Here, we image the umbrella motion of an isolated ammonia molecule (NH3) following its strong-field ionization. Upon ionization of a neutral ammonia molecule, the ammonia cation (NH3+) undergoes an ultrafast geometrical transformation from a pyramidal (𝛷����������HNH=107°) to planar (𝛷����������HNH=120°) structure in approximately 8 femtoseconds. Using LIED, we retrieve a near-planar (𝛷����������HNH=117 ± 5°) field-dressed NH3+ molecular structure 7.8−9.8 femtoseconds after ionization. Our measured field-dressed NH3+ structure is in excellent agreement with our calculated equilibrium field-dressed structure using quantum chemical ab initio calculations.Attosecond state-resolved carrier motion in quantum materials probed by soft x-ray XANESBuades, BárbaraPicón, AntonioBerger, EmmaLeón, IkerPalo, Nicola diCousin, Seth L.Cocchi, CaterinaPellegrin, EricHerrero Martin, JavierMañas-Valero, SamuelCoronado, EugenioDanz, ThomasDraxl, ClaudiaUemoto, MitsuharuYabana, KazuhiroSchultze, MartinWall, SimonZürch, MichaelBiegert, Jenshttp://hdl.handle.net/2117/3504732023-01-01T08:57:49Z2021-08-17T08:05:41ZAttosecond state-resolved carrier motion in quantum materials probed by soft x-ray XANES
Buades, Bárbara; Picón, Antonio; Berger, Emma; León, Iker; Palo, Nicola di; Cousin, Seth L.; Cocchi, Caterina; Pellegrin, Eric; Herrero Martin, Javier; Mañas-Valero, Samuel; Coronado, Eugenio; Danz, Thomas; Draxl, Claudia; Uemoto, Mitsuharu; Yabana, Kazuhiro; Schultze, Martin; Wall, Simon; Zürch, Michael; Biegert, Jens
Recent developments in attosecond technology led to table-top x-ray spectroscopy in the soft x-ray range, thus uniting the element- and state-specificity of core-level x-ray absorption spectroscopy with the time resolution to follow electronic dynamics in real-time. We describe recent work in attosecond technology and investigations into materials such as Si, SiO2, GaN, Al2O3, Ti, and TiO2, enabled by the convergence of these two capabilities. We showcase the state-of-the-art on isolated attosecond soft x-ray pulses for x-ray absorption near-edge spectroscopy to observe the 3d-state dynamics of the semi-metal TiS2 with attosecond resolution at the Ti L-edge (460 eV). We describe how the element- and state-specificity at the transition metal L-edge of the quantum material allows us to unambiguously identify how and where the optical field influences charge carriers. This precision elucidates that the Ti:3d conduction band states are efficiently photo-doped to a density of 1.9 × 1021 cm−3. The light-field induces coherent motion of intra-band carriers across 38% of the first Brillouin zone. Lastly, we describe the prospects with such unambiguous real-time observation of carrier dynamics in specific bonding or anti-bonding states and speculate that such capability will bring unprecedented opportunities toward an engineered approach for designer materials with pre-defined properties and efficiency. Examples are composites of semiconductors and insulators like Si, Ge, SiO2, GaN, BN, and quantum materials like graphene, transition metal dichalcogens, or high-Tc superconductors like NbN or LaBaCuO. Exiting are prospects to scrutinize canonical questions in multi-body physics, such as whether the electrons or lattice trigger phase transitions.
2021-08-17T08:05:41ZBuades, BárbaraPicón, AntonioBerger, EmmaLeón, IkerPalo, Nicola diCousin, Seth L.Cocchi, CaterinaPellegrin, EricHerrero Martin, JavierMañas-Valero, SamuelCoronado, EugenioDanz, ThomasDraxl, ClaudiaUemoto, MitsuharuYabana, KazuhiroSchultze, MartinWall, SimonZürch, MichaelBiegert, JensRecent developments in attosecond technology led to table-top x-ray spectroscopy in the soft x-ray range, thus uniting the element- and state-specificity of core-level x-ray absorption spectroscopy with the time resolution to follow electronic dynamics in real-time. We describe recent work in attosecond technology and investigations into materials such as Si, SiO2, GaN, Al2O3, Ti, and TiO2, enabled by the convergence of these two capabilities. We showcase the state-of-the-art on isolated attosecond soft x-ray pulses for x-ray absorption near-edge spectroscopy to observe the 3d-state dynamics of the semi-metal TiS2 with attosecond resolution at the Ti L-edge (460 eV). We describe how the element- and state-specificity at the transition metal L-edge of the quantum material allows us to unambiguously identify how and where the optical field influences charge carriers. This precision elucidates that the Ti:3d conduction band states are efficiently photo-doped to a density of 1.9 × 1021 cm−3. The light-field induces coherent motion of intra-band carriers across 38% of the first Brillouin zone. Lastly, we describe the prospects with such unambiguous real-time observation of carrier dynamics in specific bonding or anti-bonding states and speculate that such capability will bring unprecedented opportunities toward an engineered approach for designer materials with pre-defined properties and efficiency. Examples are composites of semiconductors and insulators like Si, Ge, SiO2, GaN, BN, and quantum materials like graphene, transition metal dichalcogens, or high-Tc superconductors like NbN or LaBaCuO. Exiting are prospects to scrutinize canonical questions in multi-body physics, such as whether the electrons or lattice trigger phase transitions.Molecular structure retrieval directly from laboratory-frame photoelectron spectra in laser-induced electron diffractionSánchez, A.Amini, K.Wang, S.-J.Steinle, T.Belsa, B.Danek, J.Le, A. T.Liu, X.Moshammer, R.Pfeifer, T.Richter, M.Ullrich, J.Gräfe, S.Lin, C. D.Biegert, Jenshttp://hdl.handle.net/2117/3504722022-10-13T09:41:49Z2021-08-17T07:50:32ZMolecular structure retrieval directly from laboratory-frame photoelectron spectra in laser-induced electron diffraction
Sánchez, A.; Amini, K.; Wang, S.-J.; Steinle, T.; Belsa, B.; Danek, J.; Le, A. T.; Liu, X.; Moshammer, R.; Pfeifer, T.; Richter, M.; Ullrich, J.; Gräfe, S.; Lin, C. D.; Biegert, Jens
Ubiquitous to most molecular scattering methods is the challenge to retrieve bond distance
and angle from the scattering signals since this requires convergence of pattern matching
algorithms or fitting methods. This problem is typically exacerbated when imaging larger
molecules or for dynamic systems with little a priori knowledge. Here, we employ laserinduced electron diffraction (LIED) which is a powerful means to determine the precise
atomic configuration of an isolated gas-phase molecule with picometre spatial and attosecond temporal precision. We introduce a simple molecular retrieval method, which is based
only on the identification of critical points in the oscillating molecular interference scattering
signal that is extracted directly from the laboratory-frame photoelectron spectrum. The
method is compared with a Fourier-based retrieval method, and we show that both methods
correctly retrieve the asymmetrically stretched and bent field-dressed configuration of the
asymmetric top molecule carbonyl sulfide (OCS), which is confirmed by our quantumclassical calculations.
2021-08-17T07:50:32ZSánchez, A.Amini, K.Wang, S.-J.Steinle, T.Belsa, B.Danek, J.Le, A. T.Liu, X.Moshammer, R.Pfeifer, T.Richter, M.Ullrich, J.Gräfe, S.Lin, C. D.Biegert, JensUbiquitous to most molecular scattering methods is the challenge to retrieve bond distance
and angle from the scattering signals since this requires convergence of pattern matching
algorithms or fitting methods. This problem is typically exacerbated when imaging larger
molecules or for dynamic systems with little a priori knowledge. Here, we employ laserinduced electron diffraction (LIED) which is a powerful means to determine the precise
atomic configuration of an isolated gas-phase molecule with picometre spatial and attosecond temporal precision. We introduce a simple molecular retrieval method, which is based
only on the identification of critical points in the oscillating molecular interference scattering
signal that is extracted directly from the laboratory-frame photoelectron spectrum. The
method is compared with a Fourier-based retrieval method, and we show that both methods
correctly retrieve the asymmetrically stretched and bent field-dressed configuration of the
asymmetric top molecule carbonyl sulfide (OCS), which is confirmed by our quantumclassical calculations.Transient Attosecond Soft-X-Ray Spectroscopy in Layered Semi-MetalsSidiropolous, T. P.H.Di Palo, N.Rivas, D. E.Severino, S.Reduzzi, M.Buades, B.Leon, I.Cousin, S. L.Hemmer, M.Cocchi, C.Pellegrin, E.Herrero Martin, J.Mañas-Valero, S.Coronado, E.Danz, T.Draxi, C.Uemoto, M.Yabana, K.Schultze, MartinWall, SimonPicon, A.Biegert, Jenshttp://hdl.handle.net/2117/3461432022-10-13T09:42:33Z2021-05-26T14:27:18ZTransient Attosecond Soft-X-Ray Spectroscopy in Layered Semi-Metals
Sidiropolous, T. P.H.; Di Palo, N.; Rivas, D. E.; Severino, S.; Reduzzi, M.; Buades, B.; Leon, I.; Cousin, S. L.; Hemmer, M.; Cocchi, C.; Pellegrin, E.; Herrero Martin, J.; Mañas-Valero, S.; Coronado, E.; Danz, T.; Draxi, C.; Uemoto, M.; Yabana, K.; Schultze, Martin; Wall, Simon; Picon, A.; Biegert, Jens
X-ray absorption fine-structure (XAFS) spectroscopy is a well-established technique capable of extracting information about a material’s electronic and lattice structure with atomic resolution. While the near-edge region (XANES) of a XAFS spectrum provides information about the electronic configuration, structural information is extracted from the extended XAFS (EXAFS) spectrum, consisting of several hundreds of eV above the absorption edge. With the advent of high harmonic sources, reaching photon energies in soft x-ray (SXR) region, it now becomes possible to connect the spectroscopic capabilities of XAFS to the unprecedented attosecond temporal resolution of a high harmonic source allowing the observation of electronic and lattice dynamics in real time [1,2]. Layered materials, such the transition-metal dichalcogenide TiS2 or graphite, are an emerging class of materials with attractive structural and electronic properties as they can be thinned to a single atomic layer with electron mobilities resembling that of a metal, semiconductor, or semi-metal. In this work, we utilized broadband water-window-covering attosecond SXR pulses (300 as, ranging from 200 - 550 eV) capable of accessing orbital-specific K- and L-edges of such layered materials to perform transient XAFS with attosecond time resolution [3,4]. [1] Teichmann, S. et al, "0.5-keV soft x-ray attosecond continua", Nat. Commun. 7, 11493 (2016). [2] Cousin S. et al, "Attosecond streaking in the water window: a new regime of attosecond pulse characterization", Phys. Rev. X, 7, 041030 (2017). [3] Buades, B. et al., “Dispersive soft x-ray absorption fine-structure spectroscopy in graphite with an attosecond pulse”, Optica 5 (5), 502 (2018). [4] Buades, B. et al., “Attosecond-resolved petahertz carrier motion in semi-metallic TiS2”, arXiv: 1808.06493 (2018).
2021-05-26T14:27:18ZSidiropolous, T. P.H.Di Palo, N.Rivas, D. E.Severino, S.Reduzzi, M.Buades, B.Leon, I.Cousin, S. L.Hemmer, M.Cocchi, C.Pellegrin, E.Herrero Martin, J.Mañas-Valero, S.Coronado, E.Danz, T.Draxi, C.Uemoto, M.Yabana, K.Schultze, MartinWall, SimonPicon, A.Biegert, JensX-ray absorption fine-structure (XAFS) spectroscopy is a well-established technique capable of extracting information about a material’s electronic and lattice structure with atomic resolution. While the near-edge region (XANES) of a XAFS spectrum provides information about the electronic configuration, structural information is extracted from the extended XAFS (EXAFS) spectrum, consisting of several hundreds of eV above the absorption edge. With the advent of high harmonic sources, reaching photon energies in soft x-ray (SXR) region, it now becomes possible to connect the spectroscopic capabilities of XAFS to the unprecedented attosecond temporal resolution of a high harmonic source allowing the observation of electronic and lattice dynamics in real time [1,2]. Layered materials, such the transition-metal dichalcogenide TiS2 or graphite, are an emerging class of materials with attractive structural and electronic properties as they can be thinned to a single atomic layer with electron mobilities resembling that of a metal, semiconductor, or semi-metal. In this work, we utilized broadband water-window-covering attosecond SXR pulses (300 as, ranging from 200 - 550 eV) capable of accessing orbital-specific K- and L-edges of such layered materials to perform transient XAFS with attosecond time resolution [3,4]. [1] Teichmann, S. et al, "0.5-keV soft x-ray attosecond continua", Nat. Commun. 7, 11493 (2016). [2] Cousin S. et al, "Attosecond streaking in the water window: a new regime of attosecond pulse characterization", Phys. Rev. X, 7, 041030 (2017). [3] Buades, B. et al., “Dispersive soft x-ray absorption fine-structure spectroscopy in graphite with an attosecond pulse”, Optica 5 (5), 502 (2018). [4] Buades, B. et al., “Attosecond-resolved petahertz carrier motion in semi-metallic TiS2”, arXiv: 1808.06493 (2018).Role of high ponderomotive energy in laser-induced nonsequential double ionizationShaaran, T.Camus, N.Dura, J.Fechner, L.Thai, A.Britz, A.Baudisch, M.Steinle, T.Senftleben, A.Schröter, C. D.Ullrich, J.Pfeifer, T.Keitel, C. H.Biegert, JensHatsagortsyan, K. Z.Moshammer, R.http://hdl.handle.net/2117/3454852022-10-13T09:42:14Z2021-05-12T08:59:33ZRole of high ponderomotive energy in laser-induced nonsequential double ionization
Shaaran, T.; Camus, N.; Dura, J.; Fechner, L.; Thai, A.; Britz, A.; Baudisch, M.; Steinle, T.; Senftleben, A.; Schröter, C. D.; Ullrich, J.; Pfeifer, T.; Keitel, C. H.; Biegert, Jens; Hatsagortsyan, K. Z.; Moshammer, R.
The laser-induced nonsequential double ionization (NSDI) of rare gas atoms in the near and mid-IR laser fields is studied experimentally and theoretically. We investigate electron-electron correlation at high recollision energies, experimentally achieving ponderomotive energies (Up) above 80 eV. The contribution of the two dominant channels of NSDI in the photoelectron momentum distribution, impact, and excitation ionization, are both shown to scale with ponderomotive energy and are well reproduced by theory. Surprisingly, for a large Up
in mid-IR fields, a noticeable electron-electron anticorrelation signal emerges at low photoelectron momenta, which cannot be explained by these mechanisms within state-of-the-art theoretical approaches.
2021-05-12T08:59:33ZShaaran, T.Camus, N.Dura, J.Fechner, L.Thai, A.Britz, A.Baudisch, M.Steinle, T.Senftleben, A.Schröter, C. D.Ullrich, J.Pfeifer, T.Keitel, C. H.Biegert, JensHatsagortsyan, K. Z.Moshammer, R.The laser-induced nonsequential double ionization (NSDI) of rare gas atoms in the near and mid-IR laser fields is studied experimentally and theoretically. We investigate electron-electron correlation at high recollision energies, experimentally achieving ponderomotive energies (Up) above 80 eV. The contribution of the two dominant channels of NSDI in the photoelectron momentum distribution, impact, and excitation ionization, are both shown to scale with ponderomotive energy and are well reproduced by theory. Surprisingly, for a large Up
in mid-IR fields, a noticeable electron-electron anticorrelation signal emerges at low photoelectron momenta, which cannot be explained by these mechanisms within state-of-the-art theoretical approaches.Symphony on strong field approximationAmini, KasraBiegert, JensCalegari, FrancescaChacón, AlexisCiappina, Marcelo F.Dauphin, AlexandreEfimov, Dmitry K.Figueira de Morisson Faria, CarlaGiergiel, KrzysztofGniewek, PiotrLandsman, Alexandra S.Lesiuk, MichałMandrysz, MichałMaxwell, Andrew S.Moszynski, RobertOrtmann, LisaPérez-Hernández, Jose AntonioPicón, AntonioPisanty, EmilioPrauzner-Bechcicki, JakubSacha, KrzysztofSuárez, NoslenZaïr, AmelleZakrzewski, JakubLewenstein, Maciejhttp://hdl.handle.net/2117/1709992022-05-17T11:16:13Z2019-10-28T17:00:31ZSymphony on strong field approximation
Amini, Kasra; Biegert, Jens; Calegari, Francesca; Chacón, Alexis; Ciappina, Marcelo F.; Dauphin, Alexandre; Efimov, Dmitry K.; Figueira de Morisson Faria, Carla; Giergiel, Krzysztof; Gniewek, Piotr; Landsman, Alexandra S.; Lesiuk, Michał; Mandrysz, Michał; Maxwell, Andrew S.; Moszynski, Robert; Ortmann, Lisa; Pérez-Hernández, Jose Antonio; Picón, Antonio; Pisanty, Emilio; Prauzner-Bechcicki, Jakub; Sacha, Krzysztof; Suárez, Noslen; Zaïr, Amelle; Zakrzewski, Jakub; Lewenstein, Maciej
This paper has been prepared by the Symphony collaboration (University of Warsaw,
Uniwersytet Jagielloński, DESY/CNR and ICFO) on the occasion of the 25th anniversary of
the ‘simple man’s models’ which underlie most of the phenomena that occur when intense
ultrashort laser pulses interact with matter. The phenomena in question include high-harmonic
generation (HHG), above-threshold ionization (ATI), and non-sequential multielectron
ionization (NSMI). ‘Simple man’s models’ provide both an intuitive basis for understanding
the numerical solutions of the time-dependent Schrödinger equation and the motivation for the
powerful analytic approximations generally known as the strong field approximation (SFA).
In this paper we first review the SFA in the form developed by us in the last 25 years. In this approach the SFA is a method to solve the TDSE, in which the non-perturbative interactions
are described by including continuum–continuum interactions in a systematic perturbation-like
theory. In this review we focus on recent applications of the SFA to HHG, ATI and NSMI from
multi-electron atoms and from multi-atom molecules. The main novel part of the presented
theory concerns generalizations of the SFA to: (i) time-dependent treatment of two-electron
atoms, allowing for studies of an interplay between electron impact ionization and resonant
excitation with subsequent ionization; (ii) time-dependent treatment in the single active
electron approximation of ‘large’ molecules and targets which are themselves undergoing
dynamics during the HHG or ATI processes. In particular, we formulate the general expressions
for the case of arbitrary molecules, combining input from quantum chemistry and quantum
dynamics. We formulate also theory of time-dependent separable molecular potentials to model
analytically the dynamics of realistic electronic wave packets for molecules in strong laser
fields.
2019-10-28T17:00:31ZAmini, KasraBiegert, JensCalegari, FrancescaChacón, AlexisCiappina, Marcelo F.Dauphin, AlexandreEfimov, Dmitry K.Figueira de Morisson Faria, CarlaGiergiel, KrzysztofGniewek, PiotrLandsman, Alexandra S.Lesiuk, MichałMandrysz, MichałMaxwell, Andrew S.Moszynski, RobertOrtmann, LisaPérez-Hernández, Jose AntonioPicón, AntonioPisanty, EmilioPrauzner-Bechcicki, JakubSacha, KrzysztofSuárez, NoslenZaïr, AmelleZakrzewski, JakubLewenstein, MaciejThis paper has been prepared by the Symphony collaboration (University of Warsaw,
Uniwersytet Jagielloński, DESY/CNR and ICFO) on the occasion of the 25th anniversary of
the ‘simple man’s models’ which underlie most of the phenomena that occur when intense
ultrashort laser pulses interact with matter. The phenomena in question include high-harmonic
generation (HHG), above-threshold ionization (ATI), and non-sequential multielectron
ionization (NSMI). ‘Simple man’s models’ provide both an intuitive basis for understanding
the numerical solutions of the time-dependent Schrödinger equation and the motivation for the
powerful analytic approximations generally known as the strong field approximation (SFA).
In this paper we first review the SFA in the form developed by us in the last 25 years. In this approach the SFA is a method to solve the TDSE, in which the non-perturbative interactions
are described by including continuum–continuum interactions in a systematic perturbation-like
theory. In this review we focus on recent applications of the SFA to HHG, ATI and NSMI from
multi-electron atoms and from multi-atom molecules. The main novel part of the presented
theory concerns generalizations of the SFA to: (i) time-dependent treatment of two-electron
atoms, allowing for studies of an interplay between electron impact ionization and resonant
excitation with subsequent ionization; (ii) time-dependent treatment in the single active
electron approximation of ‘large’ molecules and targets which are themselves undergoing
dynamics during the HHG or ATI processes. In particular, we formulate the general expressions
for the case of arbitrary molecules, combining input from quantum chemistry and quantum
dynamics. We formulate also theory of time-dependent separable molecular potentials to model
analytically the dynamics of realistic electronic wave packets for molecules in strong laser
fields.Ultrafast nonlinear optical response of Dirac fermions in grapheneBaudisch, MatthiasMarini, AndreaCox, Joel D.Zhu, TonySilva, FranciscoTeichmann, StephanMassicotte, MathieuKoppens, Frank H. L.Levitov, Leonid S.García de Abajo, Francisco JavierBiegert, Jenshttp://hdl.handle.net/2117/1152062022-10-13T09:52:48Z2018-03-15T09:57:25ZUltrafast nonlinear optical response of Dirac fermions in graphene
Baudisch, Matthias; Marini, Andrea; Cox, Joel D.; Zhu, Tony; Silva, Francisco; Teichmann, Stephan; Massicotte, Mathieu; Koppens, Frank H. L.; Levitov, Leonid S.; García de Abajo, Francisco Javier; Biegert, Jens
The speed of solid-state electronic devices, determined by the temporal dynamics of charge
carriers, could potentially reach unprecedented petahertz frequencies through direct
manipulation by optical fields, consisting in a million-fold increase from state-of-the-art
technology. In graphene, charge carrier manipulation is facilitated by exceptionally strong
coupling to optical fields, from which stems an important back-action of photoexcited carriers.
Here we investigate the instantaneous response of graphene to ultrafast optical fields,
elucidating the role of hot carriers on sub-100 fs timescales. The measured nonlinear
response and its dependence on interaction time and field polarization reveal the back-action
of hot carriers over timescales commensurate with the optical field. An intuitive picture is
given for the carrier trajectories in response to the optical-field polarization state. We note
that the peculiar interplay between optical fields and charge carriers in graphene may also
apply to surface states in topological insulators with similar Dirac cone dispersion relations.
2018-03-15T09:57:25ZBaudisch, MatthiasMarini, AndreaCox, Joel D.Zhu, TonySilva, FranciscoTeichmann, StephanMassicotte, MathieuKoppens, Frank H. L.Levitov, Leonid S.García de Abajo, Francisco JavierBiegert, JensThe speed of solid-state electronic devices, determined by the temporal dynamics of charge
carriers, could potentially reach unprecedented petahertz frequencies through direct
manipulation by optical fields, consisting in a million-fold increase from state-of-the-art
technology. In graphene, charge carrier manipulation is facilitated by exceptionally strong
coupling to optical fields, from which stems an important back-action of photoexcited carriers.
Here we investigate the instantaneous response of graphene to ultrafast optical fields,
elucidating the role of hot carriers on sub-100 fs timescales. The measured nonlinear
response and its dependence on interaction time and field polarization reveal the back-action
of hot carriers over timescales commensurate with the optical field. An intuitive picture is
given for the carrier trajectories in response to the optical-field polarization state. We note
that the peculiar interplay between optical fields and charge carriers in graphene may also
apply to surface states in topological insulators with similar Dirac cone dispersion relations.Next Generation Driver for Attosecond and Laser-plasma PhysicsRivas, D. E.Borot, A.Cardenas, D. E.Marcus, G.Gu, X.Herrmann, D.Xu, J.Tan, J.Kormin, D.Ma, G.Dallari, W.Tsakiris, G. D.Földes, I. B.Chou, S.-w.Weidman, M.Bergues, B.Wittmann, T.Schröder, H.Tzallas, P.Charalambidis, D.Razskazovskaya, O.Pervak, V.Krausz, F.Veisz, L.http://hdl.handle.net/2117/1069062020-07-23T23:31:19Z2017-07-27T08:37:01ZNext Generation Driver for Attosecond and Laser-plasma Physics
Rivas, D. E.; Borot, A.; Cardenas, D. E.; Marcus, G.; Gu, X.; Herrmann, D.; Xu, J.; Tan, J.; Kormin, D.; Ma, G.; Dallari, W.; Tsakiris, G. D.; Földes, I. B.; Chou, S.-w.; Weidman, M.; Bergues, B.; Wittmann, T.; Schröder, H.; Tzallas, P.; Charalambidis, D.; Razskazovskaya, O.; Pervak, V.; Krausz, F.; Veisz, L.
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 1020 W/cm2 with a pulse duration of sub-two carrier-wave cycles. The coherent combination of two sequentially amplified and complementary spectral ranges yields sub-5-fs pulses with multi-TW peak power. The application of this source allows the generation of a broad spectral continuum at 100-eV photon energy in gases as well as high-order harmonics in relativistic plasmas. Unprecedented spatio-temporal confinement of light now permits the investigation of electric-field-driven electron phenomena in the relativistic regime and ultimately the rise of next-generation intense isolated attosecond sources.
2017-07-27T08:37:01ZRivas, D. E.Borot, A.Cardenas, D. E.Marcus, G.Gu, X.Herrmann, D.Xu, J.Tan, J.Kormin, D.Ma, G.Dallari, W.Tsakiris, G. D.Földes, I. B.Chou, S.-w.Weidman, M.Bergues, B.Wittmann, T.Schröder, H.Tzallas, P.Charalambidis, D.Razskazovskaya, O.Pervak, V.Krausz, F.Veisz, L.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 1020 W/cm2 with a pulse duration of sub-two carrier-wave cycles. The coherent combination of two sequentially amplified and complementary spectral ranges yields sub-5-fs pulses with multi-TW peak power. The application of this source allows the generation of a broad spectral continuum at 100-eV photon energy in gases as well as high-order harmonics in relativistic plasmas. Unprecedented spatio-temporal confinement of light now permits the investigation of electric-field-driven electron phenomena in the relativistic regime and ultimately the rise of next-generation intense isolated attosecond sources.Ultrafast electron diffraction imaging of bond breaking in di-ionized acetyleneWolter, B.Pullen, M. G.Le, A.-T.Baudisch, M.Doblhoff-Dier, K.Senftleben, A.Hemmer, M.Schröter, C. D.Ullrich, J.Pfeifer, T.Moshammer, R.Gräfe, S.Vendrell, O.Lin, C. D.Biegert, Jenshttp://hdl.handle.net/2117/1059582020-07-23T23:31:15Z2017-06-28T15:04:18ZUltrafast electron diffraction imaging of bond breaking in di-ionized acetylene
Wolter, B.; Pullen, M. G.; Le, A.-T.; Baudisch, M.; Doblhoff-Dier, K.; Senftleben, A.; Hemmer, M.; Schröter, C. D.; Ullrich, J.; Pfeifer, T.; Moshammer, R.; Gräfe, S.; Vendrell, O.; Lin, C. D.; Biegert, Jens
Visualizing chemical reactions as they occur requires atomic spatial and femtosecond temporal resolution. Here, we report imaging of the molecular structure of acetylene (C2H2) 9 femtoseconds after ionization. Using mid-infrared laser–induced electron diffraction (LIED), we obtained snapshots as a proton departs the [C2H2]2+ ion. By introducing an additional laser field, we also demonstrate control over the ultrafast dissociation process and resolve different bond dynamics for molecules oriented parallel versus perpendicular to the LIED field. These measurements are in excellent agreement with a quantum chemical description of field-dressed molecular dynamics
2017-06-28T15:04:18ZWolter, B.Pullen, M. G.Le, A.-T.Baudisch, M.Doblhoff-Dier, K.Senftleben, A.Hemmer, M.Schröter, C. D.Ullrich, J.Pfeifer, T.Moshammer, R.Gräfe, S.Vendrell, O.Lin, C. D.Biegert, JensVisualizing chemical reactions as they occur requires atomic spatial and femtosecond temporal resolution. Here, we report imaging of the molecular structure of acetylene (C2H2) 9 femtoseconds after ionization. Using mid-infrared laser–induced electron diffraction (LIED), we obtained snapshots as a proton departs the [C2H2]2+ ion. By introducing an additional laser field, we also demonstrate control over the ultrafast dissociation process and resolve different bond dynamics for molecules oriented parallel versus perpendicular to the LIED field. These measurements are in excellent agreement with a quantum chemical description of field-dressed molecular dynamicsUltrashort pulse generation in the mid-IRPires, H.Baudisch, M.Sanchez, D.Hemmer, M.Biegert, Jenshttp://hdl.handle.net/2117/1059572022-05-17T10:28:07Z2017-06-28T14:56:54ZUltrashort pulse generation in the mid-IR
Pires, H.; Baudisch, M.; Sanchez, D.; Hemmer, M.; Biegert, Jens
Recent developments in laser sources operating in the mid-IR (3–8μm) have been motivated by the numerous possibilities for both fundamental and applied research. One example is the ability to unambiguously detect pollutants and carcinogens due to the much larger oscillator strengths of their absorption features in the mid-IR spectral region compared with the visible. Broadband sources are of particular interest for spectroscopic applications since they remove the need for arduous scanning or several lasers and allow simultaneous use of multiple absorption features thus increasing the confidence level of detection. In addition, sources capable of producing ultrashort and intense mid-IR radiation are gaining relevance in attoscience and strong-field physics due to wavelength scaling of re-collision based processes. In this paper we review the state-of-the-art in sources of coherent, pulsed mid-IR radiation. First we discuss semi-conductor based sources which are compact and turnkey, but typically do not yield short pulse duration. Mid-IR laser gain material based approaches will be discussed, either for direct broadband mid-IR lasers or as narrowband pump lasers for parametric amplification in nonlinear crystals. The main part will focus on mid-IR generation and amplification based on parametric frequency conversion, enabling highest mid-IR peak power pulses. Lastly we close with an overview of nonlinear post-compression techniques, for decreasing pulse duration to the sub-2-optical-cycle regime.
2017-06-28T14:56:54ZPires, H.Baudisch, M.Sanchez, D.Hemmer, M.Biegert, JensRecent developments in laser sources operating in the mid-IR (3–8μm) have been motivated by the numerous possibilities for both fundamental and applied research. One example is the ability to unambiguously detect pollutants and carcinogens due to the much larger oscillator strengths of their absorption features in the mid-IR spectral region compared with the visible. Broadband sources are of particular interest for spectroscopic applications since they remove the need for arduous scanning or several lasers and allow simultaneous use of multiple absorption features thus increasing the confidence level of detection. In addition, sources capable of producing ultrashort and intense mid-IR radiation are gaining relevance in attoscience and strong-field physics due to wavelength scaling of re-collision based processes. In this paper we review the state-of-the-art in sources of coherent, pulsed mid-IR radiation. First we discuss semi-conductor based sources which are compact and turnkey, but typically do not yield short pulse duration. Mid-IR laser gain material based approaches will be discussed, either for direct broadband mid-IR lasers or as narrowband pump lasers for parametric amplification in nonlinear crystals. The main part will focus on mid-IR generation and amplification based on parametric frequency conversion, enabling highest mid-IR peak power pulses. Lastly we close with an overview of nonlinear post-compression techniques, for decreasing pulse duration to the sub-2-optical-cycle regime.