71 results on '"Michael Zürch"'
Search Results
2. Polarization Dependent Excitation and High Harmonic Generation from Intense Mid-IR Laser Pulses in ZnO
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Richard Hollinger, Paul Herrmann, Viacheslav Korolev, Maximilian Zapf, Valentina Shumakova, Robert Röder, Ingo Uschmann, Audrius Pugžlys, Andrius Baltuška, Michael Zürch, Carsten Ronning, Christian Spielmann, and Daniil Kartashov
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high harmonic generation (HHG) ,ZnO ,thin film ,ellipticity dependence ,tunneling excitation ,Chemistry ,QD1-999 - Abstract
The generation of high order harmonics from femtosecond mid-IR laser pulses in ZnO has shown great potential to reveal new insight into the ultrafast electron dynamics on a few femtosecond timescale. In this work we report on the experimental investigation of photoluminescence and high-order harmonic generation (HHG) in a ZnO single crystal and polycrystalline thin film irradiated with intense femtosecond mid-IR laser pulses. The ellipticity dependence of the HHG process is experimentally studied up to the 17th harmonic order for various driving laser wavelengths in the spectral range 3–4 µm. Interband Zener tunneling is found to exhibit a significant excitation efficiency drop for circularly polarized strong-field pump pulses. For higher harmonics with energies larger than the bandgap, the measured ellipticity dependence can be quantitatively described by numerical simulations based on the density matrix equations. The ellipticity dependence of the below and above ZnO band gap harmonics as a function of the laser wavelength provides an efficient method for distinguishing the dominant HHG mechanism for different harmonic orders.
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- 2020
- Full Text
- View/download PDF
3. Extremely Nonlinear Optics Using Shaped Pulses Spectrally Broadened in an Argon- or Sulfur Hexafluoride-Filled Hollow-Core Fiber
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Andreas Hoffmann, Michael Zürch, and Christian Spielmann
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sulfur hexafluoride ,nonlinear fiber optics ,ultrashort laser pulses ,pulse-shaping ,atomic and molecular physics ,high-harmonic generation ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
In this contribution we present a comparison of the performance of spectrally broadened ultrashort pulses using a hollow-core fiber either filled with argon or sulfur hexafluoride (SF6) for demanding pulse-shaping experiments. The benefits of both gases for pulse-shaping are studied in the highly nonlinear process of high-harmonic generation. In this setup, temporally shaping the driving laser pulse leads to spectrally shaping of the output extreme ultraviolet (XUV) spectrum, where total yield and spectral selectivity in the XUV are the targets of the optimization approach. The effect of using sulfur hexafluoride for pulse-shaping the XUV yield can be doubled compared to pulse compression and pulse-shaping using argon and the spectral range for selective optimization of a single harmonic can be extended. The obtained results are of interest for extending the range of ultrafast science applications drawing on tailored XUV fields.
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- 2015
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4. Hot phonon and carrier relaxation in Si(100) determined by transient extreme ultraviolet spectroscopy
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Scott K. Cushing, Michael Zürch, Peter M. Kraus, Lucas M. Carneiro, Angela Lee, Hung-Tzu Chang, Christopher J. Kaplan, and Stephen R. Leone
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Crystallography ,QD901-999 - Abstract
The thermalization of hot carriers and phonons gives direct insight into the scattering processes that mediate electrical and thermal transport. Obtaining the scattering rates for both hot carriers and phonons currently requires multiple measurements with incommensurate timescales. Here, transient extreme-ultraviolet (XUV) spectroscopy on the silicon 2p core level at 100 eV is used to measure hot carrier and phonon thermalization in Si(100) from tens of femtoseconds to 200 ps, following photoexcitation of the indirect transition to the Δ valley at 800 nm. The ground state XUV spectrum is first theoretically predicted using a combination of a single plasmon pole model and the Bethe-Salpeter equation with density functional theory. The excited state spectrum is predicted by incorporating the electronic effects of photo-induced state-filling, broadening, and band-gap renormalization into the ground state XUV spectrum. A time-dependent lattice deformation and expansion is also required to describe the excited state spectrum. The kinetics of these structural components match the kinetics of phonons excited from the electron-phonon and phonon-phonon scattering processes following photoexcitation. Separating the contributions of electronic and structural effects on the transient XUV spectra allows the carrier population, the population of phonons involved in inter- and intra-valley electron-phonon scattering, and the population of phonons involved in phonon-phonon scattering to be quantified as a function of delay time.
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- 2018
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5. Ultrafast carrier thermalization and trapping in silicon-germanium alloy probed by extreme ultraviolet transient absorption spectroscopy
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Michael Zürch, Hung-Tzu Chang, Peter M. Kraus, Scott K. Cushing, Lauren J. Borja, Andrey Gandman, Christopher J. Kaplan, Myoung Hwan Oh, James S. Prell, David Prendergast, Chaitanya D. Pemmaraju, Daniel M. Neumark, and Stephen R. Leone
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Crystallography ,QD901-999 - Abstract
Semiconductor alloys containing silicon and germanium are of growing importance for compact and highly efficient photonic devices due to their favorable properties for direct integration into silicon platforms and wide tunability of optical parameters. Here, we report the simultaneous direct and energy-resolved probing of ultrafast electron and hole dynamics in a silicon-germanium alloy with the stoichiometry Si0.25Ge0.75 by extreme ultraviolet transient absorption spectroscopy. Probing the photoinduced dynamics of charge carriers at the germanium M4,5-edge (∼30 eV) allows the germanium atoms to be used as reporter atoms for carrier dynamics in the alloy. The photoexcitation of electrons across the direct and indirect band gap into conduction band (CB) valleys and their subsequent hot carrier relaxation are observed and compared to pure germanium, where the Ge direct ( Δ E gap , Ge , direct = 0.8 eV ) and Si0.25Ge0.75 indirect gaps ( Δ E gap , Si 0.25 Ge 0.75 , indirect = 0.95 eV ) are comparable in energy. In the alloy, comparable carrier lifetimes are observed for the X, L, and Γ valleys in the conduction band. A midgap feature associated with electrons accumulating in trap states near the CB edge following intraband thermalization is observed in the Si0.25Ge0.75 alloy. The successful implementation of the reporter atom concept for capturing the dynamics of the electronic bands by site-specific probing in solids opens a route to study carrier dynamics in more complex materials with femtosecond and sub-femtosecond temporal resolution.
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- 2017
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6. Role of free-carrier interaction in strong-field excitations in semiconductors
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U. Reislöhner, Christian Spielmann, Ingo Uschmann, Daniil Kartashov, Andrius Baltuška, François Légaré, Ellissa Haddad, Audrius Pugžlys, Michael Zürch, Valentina Shumakova, Paul Herrmann, Robert Röder, Carsten Ronning, Richard Hollinger, and Maximilian Zapf
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Physics ,business.industry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Laser ,01 natural sciences ,law.invention ,Condensed Matter::Materials Science ,Semiconductor ,law ,0103 physical sciences ,High harmonic generation ,Stimulated emission ,Atomic physics ,010306 general physics ,0210 nano-technology ,Absorption (electromagnetic radiation) ,business ,Collisional excitation ,Excitation ,Quantum tunnelling - Abstract
The interaction of laser pulses with condensed matter forms the basis of light-wave-driven electronics potentially enabling tera- and petahertz switching rate applications. Carrier control using near- and midinfrared pulses is appealing for integration into existing platforms. Toward this end, a fundamental understanding of the complexity of phenomena concerning sub-band-gap driven semiconductors such as high harmonic generation, carrier excitation due to multiphoton absorption, and interband tunneling as well as carrier-carrier interactions due to strong acceleration in infrared transients is important. Here, stimulated emission from polycrystalline ZnO thin films for pump wavelengths between 1.2 \ensuremath{\mu}m (1 eV) and 10 \ensuremath{\mu}m (0.12 eV) is observed. Contrary to the expected higher intensity threshold for longer wavelengths, the lowest threshold pump intensity for stimulated emission is obtained for the longest pump wavelength corroborating the importance of collisional excitation upon intraband electron acceleration.
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- 2021
7. Extreme Ultraviolet Second Harmonic Generation using a seeded soft X-ray laser
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Christian Spielmann, Emma Berger, J. P. Goddet, Tobias Helk, Michael Zürch, Stéphane Sebban, Fabien Tissandier, Adeline Kabacinski, L. Hoffmann, and Julien Gautier
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Materials science ,business.industry ,Second-harmonic generation ,Pulse duration ,Grating ,Laser ,Fluence ,law.invention ,Wavelength ,Optics ,law ,Extreme ultraviolet ,business ,Spectroscopy - Abstract
Non-linear interactions between light and matter are crucial for widespread applications in physical sciences, life science and engineering. Second harmonic generation (SHG) and sum-frequency generation spectroscopy in the near infrared and optical range have enabled intriguing insights into surface properties and how they influence for instance chemical reactions [1] . Expansion of these methods by developing non-linear X-ray spectroscopies has recently added the capability of studying surfaces [2] , symmetry-breaking [3] and buried interfaces [4] with elemental specificity. However, widespread application is currently limited by access to free-electron laser facilities. Here we report the first generation of second harmonic emission in the extreme ultraviolet (XUV-SHG) at the titanium M-edge. The experiments were carried out with a high-harmonic seeded SXRL [5] bringing nonlinear XUV spectroscopy with atomic specificity to the table-top. The SXRL pulses with an energy of (14 ± 2) nJ, a pulse duration of (1.73 ± 0.13) ps, wavelength of 32.8 nm and a Gaussian-like beam profile is focused down with a gold ellipsoidal mirror down to an elliptical spot with a size of roughly 20 µ m x 40 µ m. The estimated intensity on target is about of (1.0 ± 0.1)•10 10 W/cm 2 . In the focus we exceeded the damage threshold fluence of 2 mJ/cm 2 and observed single-shot damage of 50 nm Ti foils. At these intensities we also generate second harmonic light at 75.6 eV. The fundamental and SHG beams are refocused with a toroidal mirror, spectrally separated by a grating and imaged on a cooled CCD camera.
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- 2021
8. Generation of High Harmonics in Silicon Metasurfaces Boosted by Bound States in the Continuum
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George Zograf, Christian Spielmann, Daniil Kartashov, Viacheslav Korolev, Duk-Yong Choi, Sergey Kruk, Barry Luther-Davies, Kirill Koshelev, Michael Zürch, Yuri S. Kivshar, Richard Hollinger, Anastasia Zalogina, and Sergey V. Makarov
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Physics ,business.industry ,Continuum (topology) ,media_common.quotation_subject ,Physics::Optics ,Asymmetry ,Symmetry (physics) ,Harmonics ,Quantum mechanics ,Q factor ,Bound state ,High harmonic generation ,Photonics ,business ,media_common - Abstract
Bound states in the continuum (BICs) are lossless states predicted in quantum mechanics in 1929, and for the last decade, received special attention in optics and photonics as a versatile tool to achieve giant quality factors (Q factors) [1] . For ordered arrays of subwavelength meta-atoms, metasurfaces, with broken in-plane symmetry, it was shown that Q factor of quasi-BICs can be unambiguously controlled by variation of the unit cell asymmetry parameter [2] .
- Published
- 2021
9. Publisher's Note: 'Attosecond state-resolved carrier motion in quantum materials probed by soft x-ray XANES' [Appl. Phys Rev. 8, 011408 (2021)]
- Author
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Samuel Mañas-Valero, Iker Leon, Martin Schultze, Claudia Draxl, Kazuhiro Yabana, Emma Berger, Thomas Danz, Simon Wall, Seth L. Cousin, Michael Zürch, Javier Herrero Martin, Caterina Cocchi, Antonio Picón, Eric Pellegrin, Jens Biegert, Eugenio Coronado, Barbara Buades, Mitsuharu Uemoto, and Nicola Di Palo
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Physics ,Soft x ray ,Attosecond ,General Physics and Astronomy ,Motion (geometry) ,State (functional analysis) ,Atomic physics ,7. Clean energy ,Quantum ,XANES - Abstract
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.
- Published
- 2021
10. Differentiating Photoexcited Carrier and Phonon Dynamics in the Δ, L, and Γ Valleys of Si(100) with Transient Extreme Ultraviolet Spectroscopy
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Stephen R. Leone, Angela Lee, Ilana J. Porter, Scott K. Cushing, Hung-Tzu Chang, Lucas M. Carneiro, and Michael Zürch
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Technology ,Materials science ,Phonon ,02 engineering and technology ,010402 general chemistry ,Physical Chemistry ,01 natural sciences ,Molecular physics ,Condensed Matter::Materials Science ,Engineering ,Physics::Atomic and Molecular Clusters ,Physical and Theoretical Chemistry ,Spectroscopy ,Conduction band ,Condensed Matter - Materials Science ,Valence (chemistry) ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,cond-mat.mtrl-sci ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,General Energy ,Extreme ultraviolet ,Chemical Sciences ,Core level ,Condensed Matter::Strongly Correlated Electrons ,0210 nano-technology - Abstract
Transient extreme ultraviolet (XUV) spectroscopy probes core level transitions to unoccupied valence and conduction band states. Uncertainty remains to what degree the core-hole created by the XUV transition modifies the measurement of photoexcited electron and hole energies. Here, the Si {\L_{2,3}} edge is measured after photoexcitation of electrons to the {\Delta}, L, and {\Gamma} valleys of Si(100). The measured changes in the XUV transition probability do not energetically agree with the increasing electron photoexcitation energy. The data therefore experimentally confirm that, for the Si {\L_{2,3}} edge, the time-dependent electron and hole energies are partially obscured by the core-hole perturbation. A model based on many-body approximations and the Bethe-Salpeter equation is successfully used to predict the core-hole{\apos}s modification of the final transition density of states in terms of both electronic and structural dynamics. The resulting fit time constants match the excited state electron thermalization time and the inter-valley electron-phonon, intra-valley electron-phonon, and phonon-phonon scattering times previously measured in silicon. The outlined approach is a more comprehensive framework for interpreting transient XUV absorption spectra in photoexcited semiconductors.
- Published
- 2019
11. Silicon metasurfaces with bound states in the continuum for high-harmonic generation
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Christian Spielmann, Viacheslav Korolev, Sergey V. Makarov, Kirill Koshelev, Yuri S. Kivshar, Michael Zürch, George Zograf, Richard Hollinger, Barry Luther-Davies, Duk-Yong Choi, Daniil Kartashov, Sergey Kruk, and Anastasia Zalogina
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Coupling ,Physics ,Optics ,Quality (physics) ,business.industry ,Harmonics ,Bound state ,Physics::Optics ,Nonlinear optics ,High harmonic generation ,Photonics ,Polarization (waves) ,business - Abstract
Bound states in the continuum (BICs) represent dark modes trapped in the radiation continuum. BICs received significant attention in optics and photonics as a simple tool to achieve giant quality factors by transforming them into quasi-BICs. Here, we report the observation of high-harmonic generation in dielectric metasurfaces hosting BICs. The metasurface is composed of a square lattice with parallel Si bars of a slightly different width placed on a transparent substrate. The structure is engineered to support a quasi-BIC in the mid-IR with a high quality factor. We tune the metasurface asymmetry to enable the optimal coupling condition that provide the highest high-harmonic generation efficiency. In the experiment, we demonstrate the generation of odd optical harmonics from the 3rd to the 11th order in the BIC regime and study their polarization dependence. We measure the dependence of the high-harmonic signal on the input intensity. The concept of metasurfaces with highly localized light boosted by BIC resonances provides a new degree of freedom to control experimentally strong nonlinear optical response.
- Published
- 2021
12. Attosecond state-resolved carrier motion in quantum materials probed by soft x-ray XANES
- Author
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Eric Pellegrin, Jens Biegert, Michael Zürch, Eugenio Coronado, Antonio Picón, Javier Herrero Martin, Caterina Cocchi, Emma Berger, Thomas Danz, Barbara Buades, Seth L. Cousin, Martin Schultze, Kazuhiro Yabana, Simon Wall, Mitsuharu Uemoto, Iker Leon, Nicola Di Palo, Claudia Draxl, Samuel Mañas-Valero, and UAM.Departamento de Química
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Phase transition ,Materials science ,Absorption spectroscopy ,Attosecond ,General Physics and Astronomy ,FOS: Physical sciences ,02 engineering and technology ,Electron ,01 natural sciences ,7. Clean energy ,0103 physical sciences ,Spectroscopy ,010302 applied physics ,Condensed Matter - Materials Science ,Física [Àrees temàtiques de la UPC] ,business.industry ,X-Rays ,Materials Science (cond-mat.mtrl-sci) ,Física ,Òptica ,021001 nanoscience & nanotechnology ,Brillouin zone ,Semiconductor ,x-ray ,Charge carrier ,Raigs X ,Atomic physics ,0210 nano-technology ,business - Abstract
Recent developments in attosecond technology led to tabletop 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, 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 (XANES) 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 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 x 10^21 cm^-3 and that 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 towards 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, quantum materials like graphene, TMDCs, 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., 5 figures
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- 2021
13. Polarization Dependent Excitation and High Harmonic Generation from Intense Mid-IR Laser Pulses in ZnO
- Author
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Maximilian Zapf, Carsten Ronning, Andrius Baltuška, Daniil Kartashov, Michael Zürch, Ingo Uschmann, Richard Hollinger, Paul Herrmann, Robert Röder, Christian Spielmann, Viacheslav Korolev, Valentina Shumakova, and Audrius Pugžlys
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Materials science ,Photoluminescence ,Band gap ,thin film ,General Chemical Engineering ,Physics::Optics ,02 engineering and technology ,01 natural sciences ,Article ,law.invention ,lcsh:Chemistry ,Condensed Matter::Materials Science ,law ,0103 physical sciences ,Physics::Atomic and Molecular Clusters ,High harmonic generation ,General Materials Science ,Physics::Atomic Physics ,010306 general physics ,ellipticity dependence ,021001 nanoscience & nanotechnology ,Laser ,lcsh:QD1-999 ,tunneling excitation ,Harmonics ,Femtosecond ,ddc:540 ,Harmonic ,ZnO ,Atomic physics ,0210 nano-technology ,Ultrashort pulse ,high harmonic generation (HHG) - Abstract
The generation of high order harmonics from femtosecond mid-IR laser pulses in ZnO has shown great potential to reveal new insight into the ultrafast electron dynamics on a few femtosecond timescale. In this work we report on the experimental investigation of photoluminescence and high-order harmonic generation (HHG) in a ZnO single crystal and polycrystalline thin film irradiated with intense femtosecond mid-IR laser pulses. The ellipticity dependence of the HHG process is experimentally studied up to the 17th harmonic order for various driving laser wavelengths in the spectral range 3&ndash, 4 µ, m. Interband Zener tunneling is found to exhibit a significant excitation efficiency drop for circularly polarized strong-field pump pulses. For higher harmonics with energies larger than the bandgap, the measured ellipticity dependence can be quantitatively described by numerical simulations based on the density matrix equations. The ellipticity dependence of the below and above ZnO band gap harmonics as a function of the laser wavelength provides an efficient method for distinguishing the dominant HHG mechanism for different harmonic orders.
- Published
- 2020
- Full Text
- View/download PDF
14. Ptychography and Single-Shot Nanoscale Imaging with Plasma-Based Laser Sources
- Author
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T. Helk, Alexander Guggenmos, Jean-Philippe Goddet, Ulf Kleineberg, Michael Zürch, Christian Spielmann, Holger Stiel, Julien Gautier, Frederik Tuitje, Stéphane Sebban, Eduardo Oliva, and Fabien Tissandier
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Wavefront ,Materials science ,business.industry ,Amplifier ,Physics::Optics ,Plasma ,Laser ,Ptychography ,law.invention ,Wavelength ,Optics ,law ,business ,Ultrashort pulse ,Coherence (physics) - Abstract
We report the direct wavefront characterization of an intense ultrafast high-harmonic seeded soft X-ray laser at 32.8 nm wavelength and monitor the exit of the laser plasma amplifier depending on the arrival time of the seed pulses with respect to pump pulses. For the wavefront measurement in phase and intensity, we used high-resolution ptychography. After propagating the wavefront back to the source, we are able to observe the rear end of the plasma amplifier. We compare the characteristics of the seeded soft X-ray Laser to an unseeded one and find an increasing beam stability and lateral coherence important for lensless imaging techniques.
- Published
- 2020
15. Nonlinear ionization dynamics of hot dense plasma observed in a laser-plasma amplifier
- Author
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Alexander Guggenmos, Christian Spielmann, Michael Zürch, T. Helk, Stéphane Sebban, Eduardo Oliva, Fabien Tissandier, J. P. Goddet, Julien Gautier, Ulf Kleineberg, P. Martínez Gil, Frederik Tuitje, Abber Center of Photonics, Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany], Departamento de Ingeniería Energética and Instituto de Fusión Nuclear 'Guillermo Velarde', Universidad Politécnica de Madrid (UPM), Laboratoire d'optique appliquée (LOA), École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Department of Physics, Ludwig Maximilian University [Munich] (LMU), ANR-11-IDEX-0003,IPS,Idex Paris-Saclay(2011), European Project: 654148,H2020,H2020-INFRAIA-2014-2015,LASERLAB-EUROPE(2015), and European Project: 665207,H2020,H2020-FETOPEN-2014-2015-RIA,VOXEL(2015)
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lcsh:Applied optics. Photonics ,Letter ,Nonlinear optics ,Opacity ,FOS: Physical sciences ,chemistry.chemical_element ,Plasma oscillation ,01 natural sciences ,010305 fluids & plasmas ,[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph] ,Physics::Plasma Physics ,Ionization ,X-rays ,0103 physical sciences ,lcsh:QC350-467 ,ddc:530 ,010306 general physics ,plasma ,Wavefront ,Physics ,[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics] ,Krypton ,lcsh:TA1501-1820 ,Laser-produced plasmas ,Plasma ,Physics - Plasma Physics ,Atomic and Molecular Physics, and Optics ,laser ,Electronic, Optical and Magnetic Materials ,Computational physics ,Plasma Physics (physics.plasm-ph) ,chemistry ,XUV ,Extreme ultraviolet ,High-harmonic generation ,Plasma channel ,lcsh:Optics. Light ,Physics - Optics ,Optics (physics.optics) - Abstract
Light 9(1), 187 (2020). doi:10.1038/s41377-020-00424-2, Published by Nature Publishing Group, London
- Published
- 2020
- Full Text
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16. Efficient High-order Optical Harmonics Generation from Resonant Semiconductor Metasurfaces Supporting Bound States in the Continuum
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Yuri S. Kivshar, Viacheslav Korolev, Sergey V. Makarov, Sergey Kruk, Daniil Kartashov, Michael Zürch, Duk-Yong Choi, Anastasia Zalogina, Kirill Koshelev, Barry Luther-Davies, Christian Spielmann, Richard Hollinger, and George Zograf
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Physics ,Range (particle radiation) ,business.industry ,Continuum (topology) ,Physics::Optics ,Second-harmonic generation ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,010309 optics ,Semiconductor ,Q factor ,Harmonics ,0103 physical sciences ,Bound state ,Optoelectronics ,High harmonic generation ,0210 nano-technology ,business ,Astrophysics::Galaxy Astrophysics - Abstract
Through the utilization of optical bound states in the continuum supported by resonant Si metasurfaces in the mid-IR spectral range, we demonstrate the generation of odd optical harmonics, from the 3rd to the 11th order.
- Published
- 2020
17. Discrete dispersion scan setup for measuring few-cycle laser pulses in the mid-infrared
- Author
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Paul Herrmann, François Légaré, Thomas Pertsch, Michael Zürch, Nils C. Geib, Falk Eilenberger, Christian Spielmann, Richard Hollinger, Elissa Haddad, and Publica
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laser pulses ,Materials science ,Monte Carlo method ,Mid infrared ,FOS: Physical sciences ,discrete step ,02 engineering and technology ,01 natural sciences ,law.invention ,010309 optics ,Optics ,law ,0103 physical sciences ,Dispersion (optics) ,midinfrared ,business.industry ,Pulse duration ,021001 nanoscience & nanotechnology ,Laser ,optical components ,Atomic and Molecular Physics, and Optics ,Wavelength ,Interferometry ,0210 nano-technology ,business ,Phase retrieval ,material dispersion ,Optics (physics.optics) ,Physics - Optics - Abstract
In this work, we demonstrate a discrete dispersion scan scheme using a low number of flat windows to vary the dispersion of laser pulses in discrete steps. Monte Carlo simulations indicate that the pulse duration can be retrieved accurately with less than 10 dispersion steps, which we verify experimentally by measuring few-cycle pulses and material dispersion curves at 3 and 10 micrometer wavelength. This minimal measuring scheme using only five optical components without the need for high-precision positioners and interferometric alignment can be readily implemented in many wavelength ranges and situations., 4 pages, 5 figures
- Published
- 2020
18. Attosecond time-domain measurement of core-excitonic decay in magnesium oxide
- Author
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Peter M. Kraus, Lun Yue, Mette B. Gaarde, Mi-Ying Huang, Michael Zürch, Daniel M. Neumark, Christopher J. Kaplan, Jens Egebjerg Bækhøj, Kenneth J. Schafer, Romain Géneaux, Alexander Guggenmos, Stephen R. Leone, Hung-Tzu Chang, and Andrew D. Ross
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Physics ,Condensed Matter - Materials Science ,Infrared ,Exciton ,Attosecond ,General Physics and Astronomy ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,01 natural sciences ,Condensed Matter::Materials Science ,Extreme ultraviolet ,0103 physical sciences ,Quasiparticle ,Atomic physics ,010306 general physics ,Spectroscopy ,Ultrashort pulse ,Excitation - Abstract
Excitation of ionic solids with extreme ultraviolet pulses creates localized core-excitons, which in some cases couple strongly to the lattice. Here, core-excitonic states of magnesium oxide are studied in the time domain at the Mg $\text{L}_{2,3}$ edge with attosecond transient reflectivity spectroscopy. Attosecond pulses trigger the excitation of these short-lived quasiparticles, whose decay is perturbed by time-delayed near infrared optical pulses. Combined with a few-state theoretical model, this reveals that the optical pulse shifts the energy of bright core-exciton states as well as induces features arising from dark core-excitons. We report coherence lifetimes for the first two core-excitons of $2.3 \pm 0.2$ and $1.6 \pm 0.5$ femtoseconds and show that these short lifetimes are primarily a consequence of strong exciton-phonon coupling, disclosing the drastic influence of structural effects in this ultrafast relaxation process.
- Published
- 2019
19. The ultrafast X-ray spectroscopic revolution in chemical dynamics
- Author
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Peter M. Kraus, Michael Zürch, Daniel M. Neumark, Stephen R. Leone, and Scott K. Cushing
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Physics ,Pericyclic reaction ,General Chemical Engineering ,Attosecond ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Laser ,01 natural sciences ,Synchrotron ,law.invention ,Chemical Dynamics ,law ,Chemical physics ,Excited state ,0103 physical sciences ,Femtosecond ,010306 general physics ,0210 nano-technology ,Ultrashort pulse - Abstract
The past two decades have seen rapid developments in short-pulse X-ray sources, which have enabled the study of nuclear and electronic dynamics by ultrafast X-ray spectroscopies with unprecedented time resolution ranging from nanoseconds to attoseconds. In this Perspective, we discuss some of the major achievements in the study of nuclear and electronic dynamics with X-ray pulses produced by high-harmonic, free-electron-laser and synchrotron sources. The particular dynamic processes probed by X-ray radiation highlighted in this Perspective are electronic coherences on attosecond to femtosecond timescales, chemical reactions, such as dissociations, and pericyclic ring-openings, spin-crossover dynamics, ligand-exchange dynamics and structural deformations in excited states. X-ray spectroscopic probing of chemical dynamics holds great promise for the future owing to the ongoing developments of new spectroscopies, such as four-wave mixing, and the continuous improvements in emerging laboratory-based, high-harmonic sources and large-scale, facility-based, free-electron lasers.
- Published
- 2018
20. Direct and simultaneous observation of ultrafast electron and hole dynamics in germanium
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Lauren J. Borja, Scott K. Cushing, Chaitanya Das Pemmaraju, Myoung Hwan Oh, James S. Prell, Andrey Gandman, Stephen R. Leone, Christopher J. Kaplan, Hung-Tzu Chang, David Prendergast, Michael Zürch, Daniel M. Neumark, and Peter M. Kraus
- Subjects
Materials science ,Science ,physics.chem-ph ,FOS: Physical sciences ,General Physics and Astronomy ,chemistry.chemical_element ,Germanium ,02 engineering and technology ,Electron ,7. Clean energy ,01 natural sciences ,Molecular physics ,Article ,General Biochemistry, Genetics and Molecular Biology ,Condensed Matter::Materials Science ,Physics - Chemical Physics ,0103 physical sciences ,Ultrafast laser spectroscopy ,010306 general physics ,Spectroscopy ,Chemical Physics (physics.chem-ph) ,Condensed Matter - Materials Science ,Multidisciplinary ,business.industry ,Relaxation (NMR) ,Materials Science (cond-mat.mtrl-sci) ,General Chemistry ,021001 nanoscience & nanotechnology ,cond-mat.mtrl-sci ,Semiconductor ,chemistry ,Excited state ,Extreme ultraviolet ,Optoelectronics ,0210 nano-technology ,business - Abstract
Understanding excited carrier dynamics in semiconductors is crucial for the development of photovoltaics and efficient photonic devices. However, overlapping spectral features in optical pump-probe spectroscopy often render assignments of separate electron and hole carrier dynamics ambiguous. Here, ultrafast electron and hole dynamics in germanium nanocrystalline thin films are directly and simultaneously observed by ultrafast transient absorption spectroscopy in the extreme ultraviolet at the germanium M4,5 edge. We decompose the spectra into contributions of electronic state blocking and photo-induced band shifts at a carrier density of 8 × 1020 cm−3. Separate electron and hole relaxation times are observed as a function of hot carrier energies. A first-order electron and hole decay of ∼1 ps suggests a Shockley–Read–Hall recombination mechanism. The simultaneous observation of electrons and holes with extreme ultraviolet transient absorption spectroscopy paves the way for investigating few- to sub-femtosecond dynamics of both holes and electrons in complex semiconductor materials and across junctions., Understanding excited carrier dynamics in semiconductors is central to the continued development of optoelectronic devices. Using extreme ultraviolet transient absorption spectroscopy, Zürch et al. directly and simultaneously observe ultrafast electron and hole dynamics in germanium thin films.
- Published
- 2017
21. Following the plasma dynamics in a seeded soft x-ray laser with lensless imaging
- Author
-
Jean-Philippe Goddet, Julien Gautier, Ulf Kleineberg, Frederik Tuitje, Eduardo Oliva, Fabien Tissandier, Stéphane Sebban, Tobias Helk, Christian Spielmann, Alexander Guggenmos, and Michael Zürch
- Subjects
Materials science ,business.industry ,Amplifier ,Physics::Optics ,Plasma ,Laser ,Coherent diffraction imaging ,Ptychography ,law.invention ,Wavelength ,Optics ,law ,High harmonic generation ,business ,Ultrashort pulse - Abstract
We evaluated the capabilities of an intense ultrafast high-harmonic seeded soft X-ray laser at 32.8 nm wavelength regarding single-shot lensless imaging and ptychography. Additionally the wave front at the exit of the laser plasma amplifier is monitored in amplitude and phase using high resolution ptychography and backpropagation techniques.Characterizing the laser plasma amplifier performance depending on the arrival time of the seed pulse with respect to pump pulses provides insight into the light plasma interaction in the soft X-ray range.
- Published
- 2019
22. Extreme ultraviolet lensless imaging of biological specimen
- Author
-
Christian Spielmann, Frederik Tuitje, Tobias Helk, and Michael Zürch
- Subjects
Biological specimen ,Materials science ,Optics ,business.industry ,Extreme ultraviolet ,business - Published
- 2019
23. Wavelength-scale ptychographic coherent diffractive imaging using a high-order harmonic source
- Author
-
Vittoria Schuster, Jan Rothhardt, Frederik Tuitje, Michael Steinert, Wilhelm Eschen, Jens Limpert, Robert Klas, Michael Zürch, Christian Spielmann, Maxim Tschernajew, Matthias Zilk, Thomas Pertsch, Getnet K. Tadesse, and Publica
- Subjects
0301 basic medicine ,FOS: Physical sciences ,lcsh:Medicine ,Applied Physics (physics.app-ph) ,Integrated circuit ,Article ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,Optics ,law ,lcsh:Science ,Physics ,Multidisciplinary ,business.industry ,lcsh:R ,Resolution (electron density) ,Mask inspection ,Physics - Applied Physics ,Ptychography ,Other Physical Sciences ,Wavelength ,030104 developmental biology ,Extreme ultraviolet ,Harmonic ,lcsh:Q ,Biochemistry and Cell Biology ,business ,Raster scan ,ddc:600 ,030217 neurology & neurosurgery ,Optics (physics.optics) ,Physics - Optics - Abstract
Ptychography enables coherent diffractive imaging (CDI) of extended samples by raster scanning across the illuminating XUV/X-ray beam thereby generalizing the unique advantages of CDI techniques. Table-top realizations of this method are urgently needed for many applications in sciences and industry. Previously, it was only possible to image features much larger than the illuminating wavelength with table-top ptychography although knife-edge tests suggested sub-wavelength resolution. However, most real-world imaging applications require resolving of the smallest and closely-spaced features of a sample in an extended field of view. In this work, we resolve features as small as 2.5 \lambda (45 nm) by using a table-top ptychography setup and a high-order harmonic XUV source. For the first time, a Rayleigh-type criterion is used as a direct and unambiguous resolution metric for high-resolution table-top setup. This reliably qualifies this imaging system for real-world applications e.g. in biological sciences, material sciences, imaging integrated circuits and semiconductor mask inspection., Comment: 8 pages, 4 figures
- Published
- 2019
24. Single shot XUV nanoimaging using an intense femtosecond soft X-ray laser
- Author
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Frederik Tuitje, Jean-Philippe Goddet, Michael Zürch, Tobias Helk, Fabian Tissandier, Christian Spielmann, Julian Gautier, Stéphane Sebban, Ulf Kleineberg, and Alexander Guggenmos
- Subjects
Wavefront ,Soft x ray ,Materials science ,010308 nuclear & particles physics ,business.industry ,Physics ,QC1-999 ,Single shot ,Laser ,01 natural sciences ,law.invention ,Characterization (materials science) ,Optics ,law ,Extreme ultraviolet ,0103 physical sciences ,Femtosecond ,010306 general physics ,business ,Ultrashort pulse - Abstract
We report the direct wavefront characterization of an intense ultrafast high-harmonic-seeded soft X-ray laser (λ=32.8 nm) depending on the arrival time of the seed pulses by high-resolution ptychographic imaging and subsequently perform single-shot nanoscale imaging.
- Published
- 2019
25. Extremely Nonlinear Optics Using Shaped Pulses Spectrally Broadened in an Argon- or Sulfur Hexafluoride-Filled Hollow-Core Fiber
- Author
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Christian Spielmann, A. Hoffmann, and Michael Zürch
- Subjects
sulfur hexafluoride ,Femtosecond pulse shaping ,Materials science ,nonlinear fiber optics ,lcsh:Technology ,law.invention ,lcsh:Chemistry ,chemistry.chemical_compound ,Optics ,Physics::Plasma Physics ,law ,Physics::Atomic and Molecular Clusters ,High harmonic generation ,atomic and molecular physics ,high-harmonic generation ,General Materials Science ,lcsh:QH301-705.5 ,Instrumentation ,Fluid Flow and Transfer Processes ,lcsh:T ,business.industry ,Process Chemistry and Technology ,ultrashort laser pulses ,General Engineering ,Nonlinear optics ,Laser ,Pulse shaping ,lcsh:QC1-999 ,Computer Science Applications ,Sulfur hexafluoride ,lcsh:Biology (General) ,lcsh:QD1-999 ,chemistry ,lcsh:TA1-2040 ,Pulse compression ,lcsh:Engineering (General). Civil engineering (General) ,business ,Ultrashort pulse ,pulse-shaping ,lcsh:Physics - Abstract
In this contribution we present a comparison of the performance of spectrally broadened ultrashort pulses using a hollow-core fiber either filled with argon or sulfur hexafluoride (SF6) for demanding pulse-shaping experiments. The benefits of both gases for pulse-shaping are studied in the highly nonlinear process of high-harmonic generation. In this setup, temporally shaping the driving laser pulse leads to spectrally shaping of the output extreme ultraviolet (XUV) spectrum, where total yield and spectral selectivity in the XUV are the targets of the optimization approach. The effect of using sulfur hexafluoride for pulse-shaping the XUV yield can be doubled compared to pulse compression and pulse-shaping using argon and the spectral range for selective optimization of a single harmonic can be extended. The obtained results are of interest for extending the range of ultrafast science applications drawing on tailored XUV fields.
- Published
- 2015
26. Femtosecond tracking of carrier relaxation in germanium with extreme ultraviolet transient reflectivity
- Author
-
Andrew D. Ross, Peter M. Kraus, Marieke F. Jager, Eric M. Gullikson, Scott K. Cushing, Stephen R. Leone, Hung-Tzu Chang, Christopher J. Kaplan, Michael Zürch, and Daniel M. Neumark
- Subjects
Materials science ,Band gap ,Scattering ,Fluids & Plasmas ,chemistry.chemical_element ,Germanium ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Photoexcitation ,Condensed Matter::Materials Science ,Engineering ,chemistry ,Excited state ,Extreme ultraviolet ,Picosecond ,Physical Sciences ,Chemical Sciences ,0103 physical sciences ,Femtosecond ,Atomic physics ,010306 general physics ,0210 nano-technology - Abstract
© 2018 American Physical Society. Extreme ultraviolet (XUV) transient reflectivity around the germanium M4,5 edge (3d core-level to valence transition) at 30 eV is advanced to obtain the transient dielectric function of crystalline germanium [100] on femtosecond to picosecond time scales following photoexcitation by broadband visible-to-infrared (VIS/NIR) pulses. By fitting the transient dielectric function, carrier-phonon induced relaxations are extracted for the excited carrier distribution. The measurements reveal a hot electron relaxation rate of 3.2±0.2ps attributed to the X-L intervalley scattering and a hot hole relaxation rate of 600±300fs ascribed to intravalley scattering within the heavy hole (HH) band, both in good agreement with previous work. An overall energy shift of the XUV dielectric function is assigned to a thermally induced band gap shrinkage by formation of acoustic phonons, which is observed to be on a timescale of 4-5 ps, in agreement with previously measured optical phonon lifetimes. The results reveal that the transient reflectivity signal at an angle of 66 with respect to the surface normal is dominated by changes to the real part of the dielectric function, due to the near critical angle of incidence of the experiment (66-70 for the range of XUV energies used. This work provides a methodology for interpreting XUV transient reflectivity near core-level transitions, and it demonstrates the power of the XUV spectral region for measuring ultrafast excitation dynamics in solids.
- Published
- 2018
27. Coherent Diffraction Imaging with Tabletop XUV Sources
- Author
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Andreas Tünnermann, Alexander Guggenmos, C. Späth, Michael Zürch, Jan Rothhardt, S. Demmler, Holger Stiel, Christian Spielmann, Ulf Kleineberg, Steffen Hädrich, Jens Limpert, Robert Jung, and J. Tümmler
- Subjects
Physics ,business.industry ,Physics::Optics ,Laser ,Coherent diffraction imaging ,law.invention ,Wavelength ,Optics ,law ,Extreme ultraviolet ,Fiber laser ,business ,Image resolution ,Ultrashort pulse ,Coherence (physics) - Abstract
Coherent diffraction imaging (CDI) at wavelengths in the extreme ultraviolet range has become an important tool for nanoscale investigations. Employing laser-driven high harmonic sources allows for lab-scale applications such as cancer cell classification and phase-resolved surface studies in reflection geometry. The excellent beam properties support a spatial resolution below the wavelength, i.e., close to the Abbe limit. Unfortunately, the usually low photon flux of HHG sources limits their applicability. Recent advances in ultrafast fiber laser development cumulated in sources delivering average powers approaching the milliwatt level in the extreme ultraviolet. In comparison, a tabletop soft X-ray laser driven by moderate pump energies was recently employed for CDI featuring excellent temporal coherence and extraordinary high flux allowing for single-shot imaging.
- Published
- 2018
28. Electron dynamics in transition metal dichalcogenides utilizing attosecond transient absorption spectroscopy
- Author
-
Xuan Wei, Steven G. Louie, Yufeng Liang, Stephen R. Leone, Felipe H. da Jornada, Alexander Guggenmos, Chang-Ming Jiang, Romain Géneaux, Diana Y. Qiu, Hung-Tzu Chang, Adam M. Schwartzberg, Yen-Chang Chen, Vincent Tung, David Prendergast, Michael Zürch, and Daniel M. Neumark
- Subjects
Condensed Matter::Quantum Gases ,Materials science ,Absorption spectroscopy ,Condensed Matter::Other ,Exciton ,Attosecond ,02 engineering and technology ,Electron ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,01 natural sciences ,Molecular physics ,Condensed Matter::Materials Science ,Transition metal ,0103 physical sciences ,Ultrafast laser spectroscopy ,Physics::Atomic and Molecular Clusters ,010306 general physics ,0210 nano-technology ,Spectroscopy ,Absorption (electromagnetic radiation) - Abstract
© OSA 2018. Strong enhancement of exciton binding has been observed in valence-excitons in the optical regime of 2D materials. We report direct observation of long-lived core-exciton states in transition metal dichalcogenides by attosecond transient absorption spectroscopy in the XUV.
- Published
- 2018
29. 2D and 3D Nanoscale Imaging Using High Repetition Rate Laboratory-Based Soft X-Ray Sources
- Author
-
Robert Jung, Michael Zürch, Aurelie Dehlinger, Christian Seim, Bastian Pfau, A. Blechschmidt, Erik B. Malm, Holger Stiel, C. Pratsch, and J. Tümmler
- Subjects
Water window ,Microscope ,Materials science ,business.industry ,Condenser (optics) ,Holography ,Pulse duration ,Zone plate ,Laser ,Coherent diffraction imaging ,law.invention ,Optics ,law ,business - Abstract
In this contribution, we report about tomographic nanoscale imaging using a laser-produced plasma-based laboratory transmission X-ray microscope (LTXM ) in the water window. The soft X-ray radiation of the LTXM is provided by a high average power laser-produced (1.3 kHz repetition rate, 0.5 ns pulse duration, 140 W average power) plasma source, a multilayer condenser mirror, an objective zone plate, and a back-illuminated CCD camera as a detector. In the second part of the contribution, we will present recent results on holography and coherent diffraction imaging using our high repetition rate X-ray laser. We will discuss advantages of these methods and its potential for nanoscale imaging.
- Published
- 2018
30. Limitations of Extreme Nonlinear Ultrafast Nanophotonics
- Author
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Christian Spielmann, Michael Zürch, and C. Kern
- Subjects
Materials science ,Physics ,QC1-999 ,Nanophotonics ,Nanotechnology ,laser-induced damage ,ultrafast nanophontonics ,high harmonic generation ,Atomic and Molecular Physics, and Optics ,damage threshold ,Electronic, Optical and Magnetic Materials ,Nanomaterials ,Nonlinear system ,electron beam lithography ,Physics::Atomic and Molecular Clusters ,High harmonic generation ,Physics::Atomic Physics ,Electrical and Electronic Engineering ,Ultrashort pulse ,plasmonic field enhancement ,Electron-beam lithography ,Biotechnology - Abstract
High-harmonic generation (HHG) has been established as an indispensable tool in optical spectroscopy. This effect arises for instance upon illumination of a noble gas with sub-picosecond laser pulses at focussed intensities significantly greater than 1012W/cm2. HHG provides a coherent light source in the extreme ultraviolet (XUV) spectral region, which is of importance in inner shell photo ionization of many atoms and molecules. Additionally, it intrinsically features light fields with unique temporal properties. Even in its simplest realization, XUV bursts of sub-femtosecond pulse lengths are released. More sophisticated schemes open the path to attosecond physics by offering single pulses of less than 100 attoseconds duration. Resonant optical antennas are important tools for coupling and enhancing electromagnetic fields on scales below their free-space wavelength. In a special application, placing field-enhancing plasmonic nano antennas at the interaction site of an HHG experiment has been claimed to boost local laser field strengths, from insufficient initial intensities to sufficient values. This was achieved with the use of arrays of bow-tie-shaped antennas of ∼ 100nm in length. However, the feasibility of this concept depends on the vulnerability of these nano-antennas to the still intense driving laser light.We show, by looking at a set of exemplary metallic structures, that the threshold fluence Fth of laser-induced damage (LID) is a greatly limiting factor for the proposed and tested schemes along these lines.We present our findings in the context of work done by other groups, giving an assessment of the feasibility and effectiveness of the proposed scheme.
- Published
- 2015
31. Valley-dependent carrier and lattice dynamics in silicon measured by transient XUV spectroscopy
- Author
-
Scott K. Cushing, Stephen R. Leone, Michael Zürch, Hung-Tzu Chang, Lucas M. Carneiro, Chris J. Kaplan, and Peter M. Kraus
- Subjects
Physics ,Lattice dynamics ,Silicon ,Scattering ,chemistry.chemical_element ,Electron ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter::Materials Science ,chemistry ,Extreme ultraviolet ,Condensed Matter::Superconductivity ,Core level ,Condensed Matter::Strongly Correlated Electrons ,Transient (oscillation) ,Atomic physics ,Spectroscopy - Abstract
© 2017 IEEE. Transient XUV core level spectroscopy is used to resolve photoexcited electron and hole distributions, as well as carrier-phonon and phonon-phonon scattering times, in the Γ, L, and X valleys of silicon.
- Published
- 2017
32. Transverse Coherence Limited Coherent Diffraction Imaging using a Molybdenum Soft X-ray Laser Pumped at Moderate Pump Energies
- Author
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Christian Spielmann, David Attwood, Alexander Guggenmos, Ulf Kleineberg, Michael Zürch, C. Späth, Holger Stiel, Robert Jung, and J. Tümmler
- Subjects
Diffraction ,Time delay and integration ,Materials science ,Science ,02 engineering and technology ,01 natural sciences ,Article ,law.invention ,010309 optics ,Optics ,law ,0103 physical sciences ,High harmonic generation ,Multidisciplinary ,Mutual coherence ,business.industry ,021001 nanoscience & nanotechnology ,Laser ,Coherent diffraction imaging ,Other Physical Sciences ,Extreme ultraviolet ,Medicine ,Biomedical Imaging ,Biochemistry and Cell Biology ,0210 nano-technology ,business ,Coherence (physics) - Abstract
Coherent diffraction imaging (CDI) in the extreme ultraviolet has become an important tool for nanoscale investigations. Laser-driven high harmonic generation (HHG) sources allow for lab scale applications such as cancer cell classification and phase-resolved surface studies. HHG sources exhibit excellent coherence but limited photon flux due poor conversion efficiency. In contrast, table-top soft X-ray lasers (SXRL) feature excellent temporal coherence and extraordinary high flux at limited transverse coherence. Here, the performance of a SXRL pumped at moderate pump energies is evaluated for CDI and compared to a HHG source. For CDI, a lower bound for the required mutual coherence factor of |μ12| ≥ 0.75 is found by comparing a reconstruction with fixed support to a conventional characterization using double slits. A comparison of the captured diffraction signals suggests that SXRLs have the potential for imaging micron scale objects with sub-20 nm resolution in orders of magnitude shorter integration time compared to a conventional HHG source. Here, the low transverse coherence diameter limits the resolution to approximately 180 nm. The extraordinary high photon flux per laser shot, scalability towards higher repetition rate and capability of seeding with a high harmonic source opens a route for higher performance nanoscale imaging systems based on SXRLs.
- Published
- 2017
33. Hot Phonon and Carrier Relaxation in Si(100) Determined by Transient Extreme Ultraviolet Spectroscopy
- Author
-
Angela Lee, Christopher J. Kaplan, Peter M. Kraus, Lucas M. Carneiro, Hung-Tzu Chang, Stephen R. Leone, Michael Zürch, and Scott K. Cushing
- Subjects
Materials science ,Phonon ,Population ,FOS: Physical sciences ,02 engineering and technology ,7. Clean energy ,01 natural sciences ,Molecular physics ,Condensed Matter::Materials Science ,Condensed Matter::Superconductivity ,0103 physical sciences ,lcsh:QD901-999 ,010306 general physics ,Spectroscopy ,education ,Instrumentation ,education.field_of_study ,Condensed Matter - Materials Science ,Radiation ,Scattering ,Relaxation (NMR) ,Materials Science (cond-mat.mtrl-sci) ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,cond-mat.mtrl-sci ,Photoexcitation ,Excited state ,physics.optics ,Condensed Matter::Strongly Correlated Electrons ,lcsh:Crystallography ,0210 nano-technology ,Ground state ,Optics (physics.optics) ,Physics - Optics - Abstract
© 2018 Author(s). The thermalization of hot carriers and phonons gives direct insight into the scattering processes that mediate electrical and thermal transport. Obtaining the scattering rates for both hot carriers and phonons currently requires multiple measurements with incommensurate timescales. Here, transient extreme-ultraviolet (XUV) spectroscopy on the silicon 2p core level at 100 eV is used to measure hot carrier and phonon thermalization in Si(100) from tens of femtoseconds to 200 ps, following photoexcitation of the indirect transition to the Δ valley at 800 nm. The ground state XUV spectrum is first theoretically predicted using a combination of a single plasmon pole model and the Bethe-Salpeter equation with density functional theory. The excited state spectrum is predicted by incorporating the electronic effects of photo-induced state-filling, broadening, and band-gap renormalization into the ground state XUV spectrum. A time-dependent lattice deformation and expansion is also required to describe the excited state spectrum. The kinetics of these structural components match the kinetics of phonons excited from the electron-phonon and phonon-phonon scattering processes following photoexcitation. Separating the contributions of electronic and structural effects on the transient XUV spectra allows the carrier population, the population of phonons involved in inter- and intra-valley electron-phonon scattering, and the population of phonons involved in phonon-phonon scattering to be quantified as a function of delay time.
- Published
- 2017
34. Resonance-enhanced multi-octave supercontinuum generation in antiresonant hollow-core fibers
- Author
-
Rudrakant Sollapur, Daniil Kartashov, Michael Zürch, Andreas Hoffmann, Teodora Grigorova, Gregor Sauer, Alexander Hartung, Anka Schwuchow, Joerg Bierlich, Jens Kobelke, Mario Chemnitz, Markus A Schmidt, and Christian Spielmann
- Subjects
Optical fiber ,Physics::Optics ,Soliton (optics) ,Optical Physics ,02 engineering and technology ,01 natural sciences ,antiresonant hollow core fiber ,dispersion design ,law.invention ,010309 optics ,Optics ,Affordable and Clean Energy ,law ,0103 physical sciences ,Dispersion (optics) ,ddc:530 ,supercontinuum generation ,Physics ,business.industry ,nonlinear optics ,Single-mode optical fiber ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Supercontinuum ,Biophotonics ,Original Article ,soliton dynamics ,0210 nano-technology ,business ,Ultrashort pulse ,Doppler broadening - Abstract
Light 6(12), e17124 (2017). doi:10.1038/lsa.2017.124, Published by Nature Publishing Group, London
- Published
- 2017
- Full Text
- View/download PDF
35. X-ray emission generated by laser-produced plasmas from dielectric nanostructured targets
- Author
-
Björn Landgraf, Eckhart Förster, Paul Neumayer, Carsten Ronning, S. Höfer, Lukas Trefflich, Christian Spielmann, Daniil Kartashov, Zhanna Samsonova, O. N. Rosmej, Ingo Uschmann, Robert Röder, D. Khaghani, Michael Zürch, and A. Hoffmann
- Subjects
Materials science ,law ,Picosecond ,Femtosecond ,Energy conversion efficiency ,X-ray ,Nanowire ,Irradiation ,Plasma ,Atomic physics ,Laser ,law.invention - Abstract
We present an experimental study of X-ray generation from nanostructured ZnO targets. Samples of different morphology ranging from nanowires to polished surfaces are irradiated by relativistically intense femtosecond laser pulses. X-ray emission of plasma is generated by 45 fs 130 mJ laser pulses at 400 nm with picosecond temporal contrast better than 10−9 interacting with an array of ZnO nanowires. The measured spectra indicate the existence of highly ionized states of Zn (up to He-like Zn). The obtained flux of ∼1010 photons per laser shot at the neutral Zn Kα energies around 8.65 keV and at the Zn Heα energies around 9 keV is almost 3 times higher for nanostructured targets compared to the reference polished sample and implies 10−4 conversion efficiency from the laser energy to the total energy of the emitted X-ray photons.
- Published
- 2017
36. Characterization of a broadband interferometric autocorrelator for visible light with ultrashort blue laser pulses
- Author
-
Ch. Spielmann, Michael Zürch, Max Riediger, Maximilian G. O. Gräfe, A. Hoffmann, and Björn Landgraf
- Subjects
Blue laser ,Materials science ,Optical autocorrelation ,business.industry ,Autocorrelator ,Pulse duration ,Laser ,Two-photon absorption ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,Photodiode ,Optics ,law ,Optoelectronics ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,business ,Diode - Abstract
We present a compact interferometric autocorrelator that allows the characterization of ultrashort laser pulses in the visible light domain (370–740 nm). The presented device uses a GaN photodiode with corresponding two-photon absorption. Different GaN and AlGaN photodiodes were characterized for this purpose. Despite AlGaN diodes have a better matched bandgap for this application, we have found that only the GaN diodes show sufficient nonlinear behavior. Using the autocorrelator we were able to characterize ultrashort frequency doubled Ti:Sapphire laser pulses with a pulse duration down to 18 fs in the second harmonic having just a few hundred nanojoules of pulse energy. The broadband behavior and extension towards the UV along with the need for only low energetic pulses are the novelties of this device.
- Published
- 2014
37. Ultrafast transient absorption at the Germanium M4,5-edge to measure electron and hole dynamics
- Author
-
Chaitanya Das Pemmaraju, James S. Prell, Lauren J. Borja, Stephen R. Leone, Michael Zürch, Daniel M. Neumark, Andrey Gandman, and David Prendergast
- Subjects
010302 applied physics ,Physics ,Absorption spectroscopy ,Resolution (electron density) ,chemistry.chemical_element ,Germanium ,Electron ,01 natural sciences ,chemistry ,Extreme ultraviolet ,0103 physical sciences ,Ultrafast laser spectroscopy ,Physics::Atomic and Molecular Clusters ,High harmonic generation ,Density functional theory ,Atomic physics ,010306 general physics - Abstract
Extreme ultraviolet (XUV) transient absorption at the germanium M 4,5 -edge simultaneously measures electron and hole dynamics over 1.5 ps with few-femtosecond resolution. In the analysis, time-dependent density functional theory (TD-DFT) will be compared with experimental data.
- Published
- 2016
38. Retrieval of the complex-valued refractive index of germanium near the M4,5 absorption edge
- Author
-
Lauren J. Borja, Christopher J. Kaplan, Peter M. Kraus, Hung-Tzu Chang, Stephen R. Leone, Michael Zürch, Scott K. Cushing, Daniel M. Neumark, and Eric M. Gullikson
- Subjects
Total internal reflection ,Materials science ,business.industry ,Physics::Optics ,Synchrotron radiation ,chemistry.chemical_element ,Statistical and Nonlinear Physics ,Germanium ,01 natural sciences ,Electromagnetic radiation ,Atomic and Molecular Physics, and Optics ,010309 optics ,Optics ,Absorption edge ,chemistry ,Extreme ultraviolet ,0103 physical sciences ,Total external reflection ,business ,Refractive index - Abstract
The complex-valued index of refraction of germanium in the extreme ultraviolet (XUV) is measured by multi-angle reflectance of synchrotron radiation. The resulting index of refraction is higher resolution than previously measured values. It reveals new structures attributed to transitions from the 3d-core orbitals to the Σ5,2c and the X5,2c conduction bands. Additionally, it is shown that the problem of total external reflection, which renders multi-angle reflectance measurements insensitive to the complex-valued refractive index at grazing incidence, can be overcome by employing measurements at angles of incidence away from the critical angle.
- Published
- 2019
39. Perspective: Towards single shot time-resolved microscopy using short wavelength table-top light sources
- Author
-
Tobias Helk, Christian Spielmann, and Michael Zürch
- Subjects
Microscope ,Computer science ,02 engineering and technology ,01 natural sciences ,law.invention ,Optics ,law ,0103 physical sciences ,Microscopy ,lcsh:QD901-999 ,Perspectives (Invited) ,010306 general physics ,Instrumentation ,Nanoscopic scale ,Spectroscopy ,Radiation ,Single exposure ,business.industry ,Photon flux ,Single shot ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Wavelength ,ddc:500 ,lcsh:Crystallography ,0210 nano-technology ,business ,Coherence (physics) - Abstract
Structural dynamics 6(1), 010902 (2019). doi:10.1063/1.5082686, Published by AIP Publishing LLC, Melville, NY
- Published
- 2019
40. Optische Wirbel
- Author
-
C. Kern, Christian Spielmann, and Michael Zürch
- Subjects
Physics - Published
- 2013
41. Electron and Hole Dynamics in Silicon-Germanium Alloy Measured by Attosecond XUV Transient Absorption
- Author
-
Andrey Gandman, Stephen R. Leone, Lauren J. Borja, Scott K. Cushing, Hung-Tzu Chang, James S. Prell, Christopher J. Kaplan, Chaitanya Das Pemmaraju, Michael Zürch, Daniel M. Neumark, David Prendergast, and Peter M. Kraus
- Subjects
Condensed Matter::Quantum Gases ,Physics ,Attosecond ,Dynamics (mechanics) ,Alloy ,chemistry.chemical_element ,Germanium ,Electron ,engineering.material ,Silicon-germanium ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,chemistry ,Extreme ultraviolet ,Ultrafast laser spectroscopy ,Physics::Atomic and Molecular Clusters ,engineering ,Physics::Atomic Physics ,Atomic physics - Abstract
Electron-hole dynamics is measured by attosecond transient absorption in silicon-germanium alloy. The germanium atoms act as reporter atoms by time-dependent probing the M_(4,5)-edge, revealing electron and hole dynamics, as well as a new midgap feature.
- Published
- 2016
42. Attosecond transient reflectivity of electron dynamics in germanium
- Author
-
Christian Reinhold Ott, Kayla Currier, Michael Zürch, Daniel M. Neumark, Christopher J. Kaplan, Marieke F. Jager, Stephen R. Leone, Peter M. Kraus, Hung-Tzu Chang, and Lauren J. Borja
- Subjects
Materials science ,Attosecond ,Physics::Optics ,chemistry.chemical_element ,Germanium ,Condensed Matter::Materials Science ,Thermalisation ,chemistry ,Temporal resolution ,Extreme ultraviolet ,Physics::Atomic and Molecular Clusters ,Transient (oscillation) ,Atomic physics ,Refractive index ,Excitation - Abstract
Attosecond transient reflectivity in the extreme ultraviolet is developed for monitoring band-gap excitation dynamics in germanium. The investigations unravel the fastest carrier-scattering processes on the few-femtosecond time scale, and carrier thermalization on longer time scales.
- Published
- 2016
43. Octave Broadband Supercontinuum Generation in Gas-Filled Anti-Resonant Hollow-Core Fiber
- Author
-
Daniil Kartashov, Christian Spielmann, Gregor Sauer, Markus A. Schmidt, Michael Zürch, Rudrakant Sollapur, Alexander Hartung, and A. Hoffmann
- Subjects
Materials science ,business.industry ,Near-infrared spectroscopy ,Physics::Optics ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Octave (electronics) ,medicine.disease_cause ,01 natural sciences ,Supercontinuum ,010309 optics ,Wavelength ,Optics ,0103 physical sciences ,Broadband ,medicine ,Fiber ,0210 nano-technology ,business ,Ultraviolet ,Photonic-crystal fiber - Abstract
We report on octave broadband supercontinuum generation from ultraviolet to near infrared wavelengths in the fundamental mode of a gas-filled novel low-loss anti-resonant hollow-core fiber having distinct transmission windows.
- Published
- 2016
44. High Speed and High Resolution Table-Top Nanoscale Imaging
- Author
-
Andreas Tünnermann, I. Wahyutama, Christian Spielmann, R. Klas, Michael Zürch, Thomas Pertsch, S. Demmler, Michael Steinert, Jens Limpert, Jan Rothhardt, G. K. Tadesse, Steffen Hädrich, and Publica
- Subjects
Physics ,Time delay and integration ,Microscope ,business.industry ,Detector ,Resolution (electron density) ,Physics::Optics ,FOS: Physical sciences ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Numerical aperture ,law.invention ,010309 optics ,Wavelength ,Optics ,law ,Extreme ultraviolet ,Harmonics ,0103 physical sciences ,010306 general physics ,business ,Physics - Optics ,Optics (physics.optics) - Abstract
We present a table-top coherent diffraction imaging (CDI) experiment based on high-order harmonics generated at 18 nm by a high average power femtosecond fiber laser system. The high photon flux, narrow spectral bandwidth and high degree of spatial coherence allow for ultra-high sub-wavelength resolution imaging at a high numerical aperture. Our experiments demonstrate a half-pitch resolution of 13.6 nm, very close to the actual Abbe-limit of 12.4 nm, which is the highest resolution achieved from any table-top XUV or X-ray microscope. In addition, 20.5 nm resolution was achieved with only 3 sec of integration time bringing live diffraction imaging and 3D tomography on the nanoscale one step closer to reality. The current resolution is solely limited by the wavelength and the detector size. Thus, table-top nanoscopes with only a few-nm resolutions are in reach and will find applications in many areas of science and technology., Comment: 5 pages, 5 figures
- Published
- 2016
- Full Text
- View/download PDF
45. Strong-field physics with singular light beams
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Ch. Spielmann, C. Kern, Michael Zürch, A. Dreischuh, and P. Hansinger
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Physics ,Classical mechanics ,Attosecond ,Quantum mechanics ,Atoms in molecules ,Optical physics ,Physics::Optics ,General Physics and Astronomy ,Light beam ,Strong field ,Orbital angular momentum of light ,Radiation ,Optical vortex - Abstract
Optical vortices exhibit a corkscrew-like shape as they travel. The study of this phenomenon, known as singular optics, is now extended to the high-power regime where high-harmonic processes become evident. This type of radiation could help illuminate novel attosecond phenomena in atoms and molecules.
- Published
- 2012
46. Comparison of femtosecond laser-induced damage on unstructured vs. nano-structured Au-targets
- Author
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C. Kern, Christian Spielmann, Thomas Käsebier, B. Kley, Thomas Pertsch, U. Hübner, Jörg Petschulat, and Michael Zürch
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Materials science ,business.industry ,Resonance ,General Chemistry ,Radiation ,Laser ,law.invention ,Pulsed laser deposition ,Optics ,law ,Harmonics ,Femtosecond ,General Materials Science ,business ,Order of magnitude ,Plasmon - Abstract
The combination of high-field physics with nano-plasmonics has proven to be feasible in producing high harmonics of intense laser radiation from noble gases, assisted by the field-enhancement effect in the proximity of metallic nano-antennas. However, the intensity region where harmonics can be generated without irreversible damage to these delicate structures is rather narrow. We explore the damage threshold of gold targets that exhibit regular structures on a nanoscopic scale, either explicitly resonant to the used laser frequency, or off-resonance. These are compared to values for bulk material in order to gain insight into the role of plasmonic resonances in the response of solid targets on intense laser radiation. We find that the presence of such a resonance lowers the threshold fluence (J/cm2) where global structural damage sets in by about an order of magnitude. Statistical deviations either in local pulse energy of the damage inducing laser radiation or in the exact resonance behaviour of singular structures prove to be limited. These results should serve as a guideline for future experiments working near the damage threshold of more sophisticated antenna designs.
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- 2011
47. Author Correction: The ultrafast X-ray spectroscopic revolution in chemical dynamics
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Scott K. Cushing, Stephen R. Leone, Peter M. Kraus, Michael Zürch, and Daniel M. Neumark
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Physics ,General Chemical Engineering ,General Chemistry ,Ultrashort pulse ,Energy (signal processing) ,Computational physics ,Chemical Dynamics ,Gas phase - Abstract
In the original version of the article the authors inadvertently omitted to acknowledge funding from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Gas Phase Chemical Physics Program under contract no. DE-AC02-05-CH11231. This has been corrected in all versions of the published article.
- Published
- 2018
48. Extreme ultraviolet digital in-line holography using a tabletop source
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Christian Spielmann and Michael Zürch
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Physics ,business.industry ,Materials Science (miscellaneous) ,Phase-contrast imaging ,Holography ,Industrial and Manufacturing Engineering ,law.invention ,Wavelength ,Optics ,law ,Extreme ultraviolet ,Optoelectronics ,Business and International Management ,Phase retrieval ,business ,Ultrashort pulse ,Image resolution ,Digital holography - Abstract
Digital in-line holography (DIH) offers fast, lensless, and aberration-free imaging with diffraction-limited resolution and inherently combines phase- and amplitude-contrast imaging, as well as three-dimensional imaging. Extending this technique to shorter wavelengths allows increasing the achievable spatial and phase-contrast resolution, as well as accessing material parameters not accessible in the optical domain. In this paper, we report on DIH experiments conducted with a coherent tabletop ultrafast high harmonic source operated at 38 nm wavelength. Applying a twin-image-free reconstruction scheme optimized for highly absorbing samples, we were able to demonstrate the phase-contrast imaging of silicon nitride sheets of 15 nm thickness and the use of the strong absorption of extreme ultraviolet in matter for amplitude-contrast imaging of thin films with spatial resolution below 1 μm. High-resolution morphology determination in combination with phase-contrast imaging is of special importance in thin-film characterization and applications arising thereof.
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- 2015
49. Approaching the Abbe Limit in the Extreme Ultraviolet: Ultrafast Imaging Using a Compact High Average Power High Harmonic Source
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Jan Rothhardt, Steffen Hädrich, Stefan Demmler, Ulf Kleineberg, Alexander Guggenmos, Andreas Tünnermann, Christian Spielmann, Michael Zürch, Jens Limpert, and Manuel Krebs
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Physics ,business.industry ,Phase-contrast imaging ,Physics::Optics ,Flux ,Power (physics) ,Wavelength ,Optics ,Computer Science::Computer Vision and Pattern Recognition ,Extreme ultraviolet ,Limit (music) ,Harmonic ,Optoelectronics ,business ,Ultrashort pulse - Abstract
We demonstrate high-resolution imaging below one wavelength in the extreme ultraviolet using high numerical aperture diffractive imaging. Our high-average power high harmonic source at 33nm wavelength provides sufficient flux for real-time imaging.
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- 2015
50. High-Resolution Extreme Ultraviolet Microscopy
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Michael Zürch
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Materials science ,Optics ,business.industry ,Extreme ultraviolet ,Microscopy ,High resolution ,business - Published
- 2015
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