bluuebunny/crossref_metadata_2025 huggingface dataset:
Argon bubble formation in tantalum oxide-based films for gravitational wave interferometer mirrors
Authors: Cummings Rebecca B. , Bassiri Riccardo , Martin Iain W. , MacLaren Ian
Published: February 2021

The argon content of titanium dioxide doped tantalum pentoxide thin films was quantified in a spatially resolved way using high angle annular dark field (HAADF) images and DualEELS (a form of electron energy loss spectroscopy (EELS) that takes two spectra in quick succession from the highs and low-loss region). Films annealed at 300 °C, 400 °C, and 600 °C were investigated to see if there was a relationship between annealing temperature and bubble formation. It was shown using HAADF imaging that argon is present in most of these films and that bubbles of argon start to form after annealing at 400 °C and coarsen after annealing at 600 °C. A semi-empirical standard was created for the quantification using argon data from the EELS Atlas and experimental data scaled using a Hartree Slater cross-section. The density and pressure of argon within the bubbles were calculated for 35 bubbles in the 600 °C sample. The bubbles had a mean diameter, density, and pressure of 22 Å, 870 kg/m3 and 400 MPa, respectively. The pressure was calculated using the Van der Waals equation. The bubbles may affect the properties of the films, which are used as optical coatings for mirrors in gravitational wave detectors. This spatially resolved quantification technique can be readily applied to other small noble gas bubbles in a range of materials.
Different scattering effect of nano-patterned sapphire substrate for TM- and TE-polarized light emitted from AlGaN-based deep ultraviolet light-emitting diodes
Authors: Zhang Ji , Chang Le , Zhao Ziqiang , Tian Kangkai , Chu Chunshuang , Zheng Quan , Zhang Yonghui , Li Qing , Zhang Zi-Hui
Published: February 2021

In this work, the scattering mechanism by nano-patterned sapphire substrate (NPSS) for flip-chip AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) has been investigated systematically via three-dimensional finite-difference time-domain (3D FDTD) method. It is found that for the conventional DUV LED with a thick p-GaN layer, the NPSS structure can enhance the light extraction efficiency (LEE) for the transverse magnetic (TM)-polarized light because the TM-polarized light with large incident angles can be scattered into escape cones. However, the LEE for the transverse electric (TE)-polarized light is suppressed by NPSS structure because NPSS structure scatters some TE-polarized light out of the escape cones. Moreover, the highly absorptive p-GaN layer also seriously restricts the scattering efficiency of NPSS structure. Therefore, to reduce the optical absorption, meshed p-GaN structure is strongly proposed to greatly enhance the LEEs for both TM- and TE-polarized light of DUV LEDs grown on NPSS. Compared to the DUV LED with only NPSS structure and that with only meshed p-GaN layer, the LEE for the TE-polarized (TM-polarized) light for DUV LEDs with the combination of NPSS structure and meshed p-GaN structure can be enhanced by 124% (5 times) and 112% (4 times), respectively.
Smooth approximation of a varying refractive-index profile and its application in the computation of light waves
Authors: Zhu Jianxin , Yu Peipei , Zhu Zhaochen
Published: February 2021

In this paper, the smooth approximation of light waves is studied for an open optical waveguide with a distinct refractive-index profile, which involves high-precision computation of the eigenmodes and corresponding eigenfunctions. During analysis, the refractive-index function is first approximated by a quadratic spline interpolation function. Since the quadratic spline function is a polynomial of degree two in every sub-interval (sub-layer), it is equivalent to a piecewise polynomial of degree two, based on which, the corresponding Sturm-Liouville eigenvalue problem of the Helmholtz operator in sub-layer can be solved analytically by the Kummer functions. Finally, the approximate dispersion equation is established to the TE case. Obviously, the approximate dispersion equations converge fast to the exact ones, as the maximum value of the sub-interval sizes tends to zero. Furthermore, eigenmodes may be obtained by Müller’s method with suitable initial values. To refine the accuracy, the equidistant partition and the non-equidistant partition are applied to divide the interval. Numerical simulations show that the eigenfunctions of the spline interpolation are much smoother than the ones with piecewise interpolation. In addition, the non-equidistant partition can help improve the accuracy and the order of convergence of general solutions reaches the third.
Mapping Ultrafast Energy Transfer Across Electronic and Nuclear Degrees of Freedom
Authors: Arsenault Eric A. , Yoneda Yusuke , Iwai Masakazu , Niyogi Krishna K. , Fleming Graham R.
Published: February 2021

This work reinvestigates the subpicosecond energy transfer (ET) dynamics of light-harvesting complex II with two-dimensional electronic-vibrational spectroscopy (2DEV). With the help of a straightforward theoretical model, emphasis is also more generally placed on the manifestation of ET in 2DEV.
Excitonic structure and charge transfer in the Heliobacterial Reaction Center probed by multispectral multidimensional spectroscopy
Authors: Song Yin , Sechrist Riley , Johnson William , Redding Kevin E. , Ogilvie Jennifer P.
Published: February 2021

Using multidimensional multispectral spectroscopy and global-target analysis, we reveal excitonic structure and the charge transfer mechanism in the heliobacterial reaction center—the proposed closest homolog to the common ancestor of all photosynthetic reaction centers.
Non-Resonant 2 Color 2-Dimensional Electronic Spectroscopy Reveals Ground State Coherences of Light Harvesting Complex II
Authors: Irgen-Gioro Shawn , Harel Elad
Published: February 2021

Overlapping contributions from ground and excited state signals cloud interpretation of 2-Dimensional Electronic Spectroscopy. Using non-resonant interactions to suppress excited state pathways, unambiguous assignment of ground state coherences is obtained for Light Harvesting Complex II.
Probing electron-phonon couplings in halide perovskites crystals by temperature-dependent ultrafast two-dimensional electronic spectroscopy
Authors: Nguyen Xuan Trung , Timmer Daniel , Rakita Yevgeny , Cahen David , Steinhoff Alexander , Jahnke Frank , Lienau Christoph , De Sio Antonietta
Published: February 2021

We track ultrafast charge carrier relaxation and the concurrent build-up of dynamical exciton screening on a 30-fs timescale, and probe strong electron-phonon couplings in halide perovskite crystals by temperature-dependent two-dimensional electronic spectroscopy.
Time-resolved ARPES of excitons in an atomically thin semiconductor
Authors: Madéo Julien , Man Michael K. L. , Sahoo Chakradhar , Campbell Marshall , Pareek Vivek , Wong E Laine , Mahboob Abdullah Al , Chan Nicholas S. , Karmakar Arka , Mariserla Bala Murali Krishna , Li Xiaoqin , Heinz Tony F. , Cao Ting , Dani Keshav M.
Published: February 2021

We use a table-top time-resolved ARPES based on a MHz XUV source to directly observe direct and momentum-forbidden excitons in the full first Brillouin zone of WSe2 monolayer and measure their ultrafast dynamics.
Investigating Excitonic Physics in Two-Dimensional Semiconductors by Coherent Two-Dimensional Microscopy
Authors: Li Donghai , Trovatello Chiara , Dal Conte Stefano , Nuß Matthias , Soavi Giancarlo , Wang Gang , Ferrari Andrea C. , Cerullo Giulio , Brixner Tobias
Published: February 2021

Excitonic interactions determine the photoelectric properties of two-dimensional semiconductors. By using spatially resolved coherent two-dimensional micro-spectroscopy, we are able to determine the strength of exciton–phonon coupling in single-layer MoSe2 at room temperature.
Ultrafast nano-imaging of polaron dynamics in lead halide perovskites
Authors: Nishida Jun , Chang Peter T. S. , Ye Jiselle , Shaheen Sean E. , Raschke Markus B.
Published: February 2021

To investigate the spatio-temporal heterogeneity in the ultrafast soft-lattice and polaron dynamics of lead halide perovskites, we develop ultrafast heterodyne-detected infrared nano-imaging resolving nanoscale disorder in polaron formation, coupling, and dynamics.
Few-femtosecond dynamics of CO2 super-excited states
Authors: Borrego-Varillas Rocío , Lucchini Matteo , Schnappinger Thomas , Murari Mario , Lucarelli Giacinto D. , Daniele Filippo , Frassetto Fabio , Poletto Luca , de Vivie-Riedle Regina , Nisoli Mauro
Published: February 2021

Super-excited states of CO2 are studied by time-resolved photoelectron spectroscopy exploiting sub-15 fs vacuum-ultraviolet pulses. Comparison with quantum mechanical simulations allows us to identify the ultrafast mechanisms which dictate the super-excited state lifetime and coherence.
Observation of intermolecular Coulombic decay in liquid water
Authors: Zhang Pengju , Perry Conaill , Luu Tran Trung , Wörner H.J.
Published: February 2021

Intermolecular Coulombic decay has been observed in liquid water for the first time. This was achieved using monochromatized high-harmonic radiation coupled to a liquid microjet and an electron-electron coincidence spectrometer.
Modeling of Ultrafast Propagation and Quantum Kinetics for Laser-Generated Electron-Hole Plasmas in Nanowires
Authors: Gulley Jeremy R. , Huang Danhong
Published: February 2021

Simulations solve a quantum-kinetic model for ultrafast carrier dynamics in nanowires coupled to resonant scattering of laser pulses. Both transverse and resulting longitudinal electric fields play significant roles in the nanowire dynamics.
Element-Selective Probing of Photo-Driven Structural Changes in All-Inorganic Lead Perovskites
Authors: Cannelli Oliviero , Rossi Thomas , Kinschel Dominik , Budarz James , Löffler Janina , March Anne Marie , Doumy Gilles , Haddad Andre Al , Tu Ming-Feng , Kumagai Yoshiaki , Walko Donald , Smolentsev Grigory , Krieg Franziska , Kovalenko Maksym V. , Mancini Giulia F. , Chergui Majed
Published: February 2021

Out-of-equilibrium photo-induced structural changes are probed with element-selectivity in CsPbBr3 perovskite nanoparticles using 100 ps resolution time-resolved X-ray absorption spectroscopy.
Dual Nature of the Spin Relaxation Mechanism in Layered Hybrid Perovskites
Authors: Camargo Franco V. A. , Ghosh Soumen , Bourelle Sean A. , Shivanna Ravichandran , Friend Richard H. , Cerullo Giulio , Deschler Felix
Published: February 2021

Two-dimensional layered perovskites are promising for spintronics, as crystal symmetry and spin-orbit coupling are tunable. We study a lead-iodide Ruddlesden-Popper hybrid perovskite with ultrafast Faraday rotation, finding different spin relaxation mechanisms for different absorption bands.
Attosecond Spectroscopy of Ultrafast Carrier Dynamics in Nanoparticles
Authors: Lackner Florian , Gessner Julia A. , Siegrist Florian , Schiffmann Alexander , Messner Roman , Lasserus Maximilian , Schnedlitz Martin , Toulson Benjamin W. , Knez Daniel , Hofer Ferdinand , Gessner Oliver , Ernst Wolfgang E. , Schultze Martin
Published: February 2021

The electronic response of surface deposited nanoparticles to a few-cycle near infrared pump pulse is traced by attosecond XUV transient absorption spectroscopy.
Strong Exciton-Coherent Phonon Coupling in Single-Layer MoS2
Authors: Trovatello Chiara , Miranda Henrique P. C. , Molina-Sánchez Alejandro , Varillas Rocío Borrego , Manzoni Cristian , Moretti Luca , Ganzer Lucia , Maiuri Margherita , Wang Junjia , Dumcenco Dumitru , Kis Andras , Soavi Giancarlo , Marini Andrea , Wirtz Ludger , Ferrari Andrea C. , Cerullo Giulio , Sangalli Davide , Conte Stefano Dal
Published: February 2021

Broadband transient absorption with sub-20fs temporal resolution, supported by ab-initio calculations, quantitatively provides the strength of exciton-coherent phonon coupling in 1L-MoS2, showing a resonant profile around the C exciton.
Transient Extreme Ultraviolet Measurement of Carrier Dynamics in Solar Fuel Materials
Authors: Michelsen Jonathan M. , Liu Hanzhe , Cushing Scott K.
Published: February 2021

Element-specific charge transfer dynamics are measured in solar fuel materials using ultrafast extreme ultraviolet pulses. This includes hole transport in a Si-TiO2-Ni photoelectrode and the role of polarons in metal oxide photocatalysts.
A Topological View on Metasurfaces Susceptibilities
Authors: Saurabh Prasoon , Dorfman Konstantin
Published: February 2021

We present an alternative approach to understanding purely topological origin of the optical signals in the arbitrarily shaped metasurfaces by combining traditional non-local Green’s functions treatment for microscopic material descriptions with the tools of differential geometry.
Ultrafast photoinduced mechanical distortion of carbon nanotubes via electronic excitation
Authors: Nakayama Tomohito , Tanaka Takeshi , Hirano Atsushi , Hase Muneaki
Published: February 2021

Using ultrafast pump-probe spectroscopy combined with a time-partitioning Fourier transform, we demonstrate transient mechanical distortion of Single-wall carbon nanotubes by photoexcitation assisted by protein adsorption.
Sub-100 fs Hole Transfer Dynamics in WS2/MoS2 Heterostructure Probed by Two-Dimensional Electronic Spectroscopy
Authors: Policht Veronica R. , Russo Mattia , Trovatello Chiara , Liu Fang , De Silvestri Sandro , Maiuri Margherita , Conte Stefano Dal , Zhu Xiaoyang , Cerullo Giulio
Published: February 2021

We study the exciton and carrier dynamics in large-area WS2/MoS2 heterostructures using ultrafast two-dimensional electronic spectroscopy. With 30 fs resolution we are able to resolve interlayer hole transfer on sub-100 fs timescale.
Hot Carrier Tunneling in Graphene/WS2 Heterostructures
Authors: Trovatello Chiara , Piccinini Giulia , Forti Stiven , Fabbri Filippo , Rossi Antonio , Coletti Camilla , Cerullo Giulio , Dal Conte Stefano
Published: February 2021

We investigate charge transfer dynamics in graphene/WS2 heterostructures via transient reflection spectroscopy. By selectively exciting graphene with NIR sub-20fs pulses we resolve the build-up of the WS2 excitonic transitions due to the hot-carriers tunneling.
Surface Electron Dynamics in TiO2 Probed by Ultrafast XUV Spectroscopy: Understanding the Role of O Vacancy Defects
Authors: Baker L. Robert , Hruska Emily , Husek Jakub
Published: February 2021

Using XUV reflection-absorption spectroscopy, we study the ultrafast surface electron dynamics in TiO2 with emphasis on the role of O vacancies and excitation wavelength. We identify unique photoexcited states as a function of excitation wavelength.
Plasmon Induced Ultrafast Excited State Interfacial Electron Dynamics of Tetrathiafulvalene Sensitizers
Authors: Biswas Chinmoy , Katturi Krishnakanth Naga , Duvva Naresh , Giribabu Lingamallu , Soma Venugopal Rao , Raavi Sai Santosh Kumar
Published: February 2021

Silver (Ag) nanoparticle induced enhanced electron-injection and reduced charge-recombination dynamics in two thioalkyl substituted tetrathiafulvalene dye (G1 and G3)- sensitized mesoporous TiO2 layers have been investigated using femtosecond transient-absorption spectroscopy with 400 nm excitation.
Chemical Species Imaging in Flames Using Frequency-Tripled Tunable Amplified Femtosecond Laser Pulses
Authors: Wang Yejun , Parajuli Pradeep , Jain Ayush , Kulatilaka Waruna D.
Published: February 2021

A direct frequency-conversion third-harmonic-generation system pumped by a tunable amplified femtosecond laser is developed for OH and CO planar imaging. Increased output energies and the robust operation enables high-fidelity single-shot OH images in turbulent flames.
Heteromolecular exciton delocalization and heterofission in tetracene – pentacene blends
Authors: Zeiser Clemens , Moretti Luca , Lepple Daniel , Maiuri Margherita , Cerullo Giulio , Broch Katharina
Published: February 2021

Singlet exciton fission in heteromolecular systems holds great potential for application in organic photovoltaics. We study tetracene:pentacene mixed films using femtosecond transient absorption spectroscopy and find signs of heteromolecular interaction upon excitation of pentacene.
Ultrafast intersystem crossing in 4-thiothymidine proceeds through a vibrational coherently accessed dark intermediate state
Authors: Teles Ferreira D. C. , van Stokkum I. H. M. , Borrego-Varillas R. , Ganzer L. , Manzoni C. , De Silvestri S. , Cerullo G. , de Paula A. M.
Published: February 2021

4-Thiothymidine 20 fs broadband Transient Transmission Spectroscopy results and analysis provide evidence that along the photoexcited relaxation pathway, the intersystem crossing originates primarily from a dark intermediate state, which is vibrationally coherent accessible.
Switching Between Ultrafast Proton Vacancy and Excess Proton Transfer along a Methanol Solvent Bridge
Authors: Codescu Marius-Andrei , Kornilov Oleg , Nibbering Erik T. J.
Published: February 2021

We show how ultrafast acid-base proton transfer neutralization reactions along methanol solvent bridges can be steered from a sequential methoxide to a sequential excess proton transport pathway.
Investigation of Complex Relaxation Dynamics of Nearly Degenerated Rydberg States in Acetone
Authors: Heim Pascal , Mai Sebastian , Thaler Bernhard , Cesnik Stefan , Avagliano Davide , Bella-Velidou Dimitra , Ernst Wolfgang E. , Gonzales Leticia , Koch Markus
Published: February 2021

By combining time-resolved photoelectron spectroscopy with surface-hopping simulations we disentangle for the first time the ultrafast population transfer between the closely spaced and strongly coupled n3p Rydberg states of acetone.
Single and Double Ionization of Aligned NO Radical in Intense Femtosecond Laser Fields
Authors: Fukahori Shinichi , Iwasaki Atsushi , Yamanouchi Kaoru , Hasegawa Hirokazu
Published: February 2021

The alignment-dependent sequential-double-ionization probability of NO in intense laser fields is determined by the shape of the 5σ orbital, from which the second photoelectron is ejected associated with the saturation of the first ionization.
Exciton trapping dynamics in DNA oligonucleotides tracked with sub-20 fs UV pulses
Authors: Borrego-Varillas R. , Cerullo G. , Markovitsi D.
Published: February 2021

We report transient absorption measurements on adenine single strands with unprecedented temporal resolution of 30 fs. We show that internal conversion among exciton states occurs within 100 fs, while charge-transfer states form within 3 ps.
A Theoretical Study of Polarization Selective Two-Dimensional Vibronic Spectroscopies of Multimode Systems
Authors: Weakly Robert B. , Gaynor James D. , Khalil Munira
Published: February 2021

A model vibronic Hamiltonian composed of coupled anharmonic vibrational modes and two electronic states provides a quantitative framework for understanding how vibronic couplings and dipole orientations are encoded in two-dimensional vibronic spectroscopy.
Ultrafast processes of atoms and molecules inside a quantum fluid
Authors: Thaler Bernhard , Heim Pascal , Meyer Miriam , Treiber Leonhard , Stadlhofer Michael , Ernst Wolfgang E. , Koch Markus
Published: February 2021

Helium nanodropletse offer fascinating opportunities for ultrafast studies in cold, controlled environments. We explore this potential by studying femtosecond dynamics of solvated atoms and diatomics, and find distinctive signatures of both intramolecular and solvent-specific dynamics.
Primary photoinduced processes in tryptophan tracked with sub-20-fs UV pulses
Authors: Kabaciński P. , Borrego-Varillas R. , Nogueira de Faria B. E. , Gentile M.G. , Conti I. , De Silvestri S. , Garavelli M. , De Paula A. M. , Cerullo G.
Published: February 2021

We report sub-20-fs resolution UV transient absorption measurements, supported by ab-initio simulations, of the primary photoinduced processes of tryptophan in solution. We show internal conversion occurring in 300-fs followed by intersystem crossing in 1-ps.
Ultrafast Photophysical Investigations of water-soluble triphenylmethane derivative (New Fuchsin) molecule
Authors: Biswas Chinmoy , Bhattacharya Somdatta , Soma Venugopal Rao , Raavi Sai Santosh Kumar
Published: February 2021

Ultrafast excited-state molecular relaxation process in a triphenylmethane derivative dye New Fuchsin (NF) for dye-sensitized solar cell application in solution and thin film is studied using femtosecond pump-probe spectroscopy at pump excitation wavelength 550 nm.
Population inversion between B2Σu+ and X2Σg+ states of N2+ assisted by rotational excitation
Authors: Zhang Youyuan , Lötstedt Erik , Yamanouchi Kaoru
Published: February 2021

We investigate the rotational population inversion between the electronically excited B state and the ground X state in N2+ generated in an intense laser field by including electronic, vibrational and rotational degrees of freedom.
Ultrafast ion- and electron-spectroscopy with soft X-rays at the European XFEL
Authors: Rivas Daniel E. , Grychtol Patrik , Baumann Thomas M. , Boll Rebecca , Erk Benjamin , de Fanis Alberto , Grünert Jan , Ilchen Markus , Liu Jia , Mazza Tommaso , Montaño Jacobo , Music Valerija , Ovcharenko Yevheniy , Rennhack Nils , Rouzée Arnaud , Rörig Aljoscha , Schmidt Philipp , Usenko Sergey , Wagner René , Ziółkowski Pawel , Meyer Michael
Published: February 2021

We present the first pump/probe measurements performed at the SQS instrument of the European XFEL. We obtain the first characterization of the femtosecond temporal resolution and show the feasibility for the investigation of ultrafast dynamics.
X-ray Photoelectron Angular Distributions from Organic Molecules by Femtosecond Soft X-ray Free Electron Lasers at PAL-XFEL
Authors: Minemoto Shinichirou , Teramoto Takahiro , Majima Takuya , Mizuno Tomoya , Mun Je Hoi , Yagishita Akira
Published: February 2021

We are developing an ultrafast X-ray photoelectron diffraction by using soft X-ray FEL. On the way to the final goal, we have measured degree of alignment of iodobenzene molecules and I 3d photoelectrons from them.
Investigations of the Energy Transfer in the Phycobilisome Antenna of Arthrospira Plantesis Using Time Resolved Absorption and Fluorescence Spectroscopy
Authors: Falamas Alexandra , Porav Sebastian Alin , Dragos Nicolae , Tosa Valer
Published: February 2021

We present the ultrafast dynamics in a phycobilisome and its components, phycocyanin and allophycocyanin phycobiliproteins. Transient absorption, as well as time correlated single photon counting investigations are presented and discussed.
Structural Discrimination of Phosphate Contact Ion Pairs in Water by Femtosecond 2D-IR Spectroscopy
Authors: Kundu Achintya , Schauss Jakob , Fingerhut Benjamin P. , Elsaesser Thomas
Published: February 2021

The distinct structures of contact ion pairs in water are identified. Nonlinear infrared (IR) spectroscopy and theoretical calculations allow for the separation and assignment of spectral features and interactions.
Heme Doming in Ferric Cytochrome c: Femtosecond X-ray Absorption and X-ray Emission Studies
Authors: Bacellar Camila , Kinschel Dominik , Mancini Giulia F. , Ingle Rebecca A. , Rouxel Jérémy , Cannelli Oliviero , Cirelli Claudio , Knopp Gregor , Szlachetko Jakub , Lima Frederico A. , Menzi Samuel , Pamfilidis Georgios , Kubicek Katharina , Khakhulin Dmitry , Gawelda Wojciech , Rodriguez-Fernandez Angel , Biednov Mykola , Bressler Christian , Arrell Christopher A. , Johnson Philip J. M. , Milne Christopher , Chergui Majed
Published: February 2021

The photoinduced dynamics of ferric Cytochrome c was investigated by ultrafast non-resonant X-ray emission (XES) and X-Ray Absorption (XAS) spectroscopies, and a cascade through high spin states accompanied by heme doming are observed for the first time.
Ultrafast Charge Transfer and Electron Delocalization in a Cyanide-Bridged Ru-Ru Dimer Investigated with Femtosecond Transient X-Ray and IR Spectroscopies
Authors: Poulter Benjamin I. , Biasin Elisa , Liekhus-Schmaltz Chelsea , Arrell Christopher , Augustin Sven , Cirelli Claudio , Cordones-Hahn Amy , Johnson Phillip , Knopp Gregor , Milne Christopher , Mori Roberto Alonso , Ozerov Dmitry , Reinhard Marco , Sandwisch Jason W. , Sokaras Dimosthenis , Usov Ivan , Weakly Robert B. , Govind Niranjan , Schoenlein Robert W. , Khalil Munira
Published: February 2021

Transient IR and X-Ray spectroscopies were used to investigate excited state delocalization of a mixed valence Ru based donor-bridge-acceptor complex on a femtosecond timescale revealing the role of the electron density on the Ru-CN-Ru fragment.
Molecular annihilation dynamics measured in the perturbative regime of excitation
Authors: Malevich Pavel , Heshmatpour Constantin , Ceymann Harald , Schreck Maximilian Hubert , Hauer Juergen
Published: February 2021

We present a fully non-collinear 50 kHz shot-to-shot detected two-dimensional electronic spectroscopy setup for directly studying bi-exciton relaxation dynamics via 5th order signals. The measurements report on annihilation timescales at a single, perturbative excitation energy.
Probing Exciton Transport in Squaraine Polymers Using Fifth-Order Two-Dimensional Spectroscopy
Authors: Lüttig Julian , Malý Pavel , Turkin Arthur , Mayershofer Katja , Büttner Simon , Lambert Christoph , Brixner Tobias
Published: February 2021

We use the technique of exciton–exciton-interaction two-dimensional spectroscopy to investigate exciton transport in squaraine copolymers. We reveal the influence of the polymer chain conformation by comparing the exciton dynamics in H-and J-type polymers.
Packing Morphology-Dependent Singlet Fission in Single Crystal Anthradithiophene Derivatives
Authors: Mayonado Gina , Vogt Kyle T. , Van Schenck Jonathan D. B. , Ostroverkhova Oksana , Graham Matt W.
Published: February 2021

Single crystal excited state dynamics in functionalized anthradithiophene (ADT) derivatives were compared across four distinct packing morphologies. Using polarization-dependent transient absorption microscopy, morphology-dependent singlet fission was observed in only three of the four ADT derivatives.
Probing atomic motions accompanying singlet exciton fission in pentacene
Authors: Seiler Hélène , Krynski Marcin , Zahn Daniela , Windsor Yoav William , Vasileiadis Thomas , Hammer Sebastian , Pflaum Jens , Rossi Mariana , Ernstorfer Ralph , Schwoerer Heinrich
Published: February 2021

We investigate the structural dynamics accompanying singlet fission in pen-tacene single crystals with femtosecond electron diffraction. The data reveal incoherent and coherent contributions to the structural dynamics. We discuss the implications for singlet fission properties.
Ultrafast Dynamics of Molecular Motors Driven by Near-Infrared Light
Authors: Hoang Nong V. , Pfeifer Lukas , Feringa Ben L. , Pshenichnikov Maxim S.
Published: February 2021

Dye-sensitization of a molecular motor allowed its functioning under two-photon near-infrared excitation. Ultrafast transient absorption spectroscopy was used to verify energy transfer from the sensitizer to the motor and motor’s subsequent rotation.
Extreme-ultraviolet time-resolved photoelectron spectroscopy of the photoisomerisation dynamics of cis-stilbene in the gas and liquid phases
Authors: Wang C. , Waters M. D. J. , Zhang P. , Luu T. T. , Svoboda V. , Perry C. , Yin Z. , Wörner H. J.
Published: February 2021

Measuring time-resolved photoelectron spectra of liquids, and achieving photon energies to probe electronic ground states is challenging. We present gas- and liquid-phase XUV-TRPES of cis-stilbene, providing new insight into this prototype of molecular photoisomerisation dynamics.
Ultrafast Conical Intersection Dynamics Monitored Through Electronic Coherences by Stimulated X-Ray Raman Signals
Authors: Mukamel Shaul , Schnappinger Thomas , de Vivie-Riedle Regina , Keefer Daniel
Published: February 2021

Coherences at conical intersections are probed by X-Ray stimulated Raman signals. Contrary to the common picture of short femtosecond and precisely timed nonadiabatic passages, the distinctly visible coherence signature survives for a much longer time.
Relaxation and Coherence Transfer in Dual-Mode Vibrational Polaritons Tracked with 2DIR
Authors: Duan Rong , Mastron Joseph , Song Yin , Kubarych Kevin
Published: February 2021

Strong coupling between microcavities and molecular vibrations may enable direct, external control over chemical dynamics. We use ultrafast 2DIR to probe a unique system with two vibrational modes strongly coupled to two distinct cavity modes.
Electron–vibrational coupling dynamics in SF6
Authors: Rupprecht Patrick , Aufleger Lennart , Magunia Alexander , Heinze Simon , Ding Thomas , Rebholz Marc , Amberg Stefano , Mollov Nikola , Henrich Felix , Haverkort Maurits , Ott Christian , Pfeifer Thomas
Published: February 2021

We report on soft x-ray transient absorption spectroscopy in SF6. The influences of strong SWIR fields and of impulsive stimulated Raman scattering initiatedν1vi-brational breathing mode dynamics on the 6a1g(S 2p1/2,3/2)-1resonance are investigated.
Role of intraband dynamics on circularly polarized high-harmonic generation from solids
Authors: Klemke Nicolai , Tancogne-Dejean Nicolas , Rubio Angel , Kärtner Franz X. , Mü Oliver D.
Published: February 2021

We perform single-particle intraband-only calculations to study the origin of circularly polarized higher-order harmonics from solids. The simulation results are compared to new experimental data on high-harmonic generation in zinc sulfide.
Tracking Ultrafast Solid-State Dynamics in VO2 Using High Harmonic Spectroscopy
Authors: Bionta Mina R. , Haddad Elissa , Leblanc Adrien , Gruson Vincent , Lassonde Philippe , Ibrahim Heide , Chaillou Jérémie , Émond Nicolas , Otto Martin R. , Siwick Bradley J. , Chaker Mohamed , Légaré François
Published: February 2021

We extend time-resolved high harmonic spectroscopy to solid-state systems by investigating the dynamics of the insulator-to-metal phase transition in the strongly correlated material, VO2, revealing all electronic states involved.
Nonlinear Terahertz Response of Solvated Electrons in Liquid Water
Authors: Ghalgaoui A. , Fingerhut B. P. , Reimann K. , Woerner M. , Elsaesser T.
Published: February 2021

In presence of a strong terahertz field, intermolecular electric fields induce tunnel ionization of water molecules. The generated electrons display a polaronic response characterized by coherent oscillations and persistent changes of the terahertz dielectric function.
Guiding of Laser Pulses at the Theoretical Limit – 97% Throughput Hollow-Core Fibers
Authors: Jeong Young-Gyun , Piccoli Riccardo , Rovere Andrea , Zanotto Luca , Tempea Gabriel , Wilson Derrek , Ivanov Maksym , Ramirez Alicia , Morandotti Roberto , Légaré François , Razzari Luca , Schmidt Bruno E.
Published: February 2021

We describe a compact, 1-m-long, hollow-core fiber (HCF) with 97.4% transmission. 1mJ, 170fs pulses are compressed to 25fs with 92% total efficiency, energy stability of 0.6% RMS and an M2 parameter of about 1.05.
Quantum path interference of photoemissions from metal nanotips in two-color laser fields
Authors: Li Ang , Pan Yiming , Dienstbier Philip , Hommelhoff Peter
Published: February 2021

We show that two-color quantum path interference from metal nanotips exhibits 90%+ visibility over an almost octave-spanning wavelength range (1180-2000 nm). Theoretical modeling explains this and other intricate features of two-color quantum path physics.
Implementation of Broadband near-UV Pump Pulses for Ultrafast 2D Electronic-Vibrational Spectroscopy
Authors: Sandwisch Jason W. , Gaynor James D. , Khalil Munira
Published: February 2021

We present the generation of efficient, tunable sub-20 fs broadband near UV pulses. The tunable pulses are used in two-dimensional electronic-vibrational spectroscopy and reveal additional vibronic states in an excited state intramolecular proton transfer process.
Vibronic Coherence Evolution in Ultrafast Charge Transfer
Authors: Gaynor James D. , Sandwisch Jason W. , Khalil Munira
Published: February 2021

The photoexcited charge transfer of the well-known dye molecule, “N34-”, is investigated using multidimensional (2D and 3D) EV spectroscopy. Vibronic coherences are shown to be central in its nonadiabatic photoexcited relaxation.
Hot Electron Transfer in Hybrid Semiconductor-Metal Nanorods Investigated with Two-Dimensional Electronic Spectroscopy
Authors: Camargo Franco V. A. , Nagahara Tetsuhiko , Ben-Shahar Yuval , Panfil Yossef E. , Russo Mattia , Banin Uri , Cerullo Giulio
Published: February 2021

Hybrid semiconductor-metal nanorods are very promising photocatalytic materials. We apply two-dimensional electronic spectroscopy to CdSe nanorods with gold tips, unravelling the mixing of electronic states, hot electron transfer and relaxation with sub-10 fs temporal resolution.
Deciphering Photoacidity by Following Electronic Charge Distribution Changes along the Photoacid Förster Cycle with Time-Resolved Nitrogen K-Edge X-Ray Absorption Spectroscopy
Authors: Eckert Sebastian , Winghart Marc-Oliver , Kleine Carlo , Banerjee Ambar , Ekimova Maria , Ludwig Jan , Harich Jessica , Mitzner Rolf , Aminov Daniel , Pines Dina , Pines Ehud , Huse Nils , Wernet Philippe , Odelius Michael , Nibbering Erik T. J.
Published: February 2021

We locally probe with picosecond N K-edge spectroscopy electronic structure changes along all stages of the Förster photocycle of a prototypical photoacid, and determine how photoacid behaviour is driven by the conjugate photobase side.
Multi-cycle terahertz driven ultrafast electron manipulation in dielectrically-lined waveguides
Authors: Zhang Dongfang , Fakhari Moein , Cankaya Huseyin , Calendron Anne-Laure , Matlis Nicholas H. , Kärtner Franz X.
Published: February 2021

We report on multi-cycle THz driven electron manipulations (acceleration, compression, and focusing) in dielectrically-lined waveguides. Cascaded acceleration by recycling and re-phasing of THz pulses is demonstrated.
Deep-Learning CARS: Real-Time Removal of the Non-Resonant Background
Authors: Valensise Carlo M. , Giuseppi Alessandro , Vernuccio Federico , De la Cadena Alejandro , Cerullo Giulio , Polli Dario
Published: February 2021

We introduce a novel approach based on deep learning to remove non-resonant background from coherent anti-Stokes Raman scattering spectra in real time. The model is trained on synthetic spectra and successfully applied to experimental data.
Ultrafast nonadiabatic dynamics through an intermolecular conical intersection
Authors: De Sio Antonietta , Sommer Ephraim , Gross Lynn , Nguyen Xuan Trung , Popović Duško , Mena-Osteritz Elena , Bäuerle Peter , Frauenheim Thomas , Tretiak Sergei , Lienau Christoph
Published: February 2021

Combining <10-fs two-dimensional electronic spectroscopy and atomistic nonadiabatic dynamics simulations, we track, for the first time, vibrational wavepacket motion through an intermolecular conical intersection governing the sub-100-fs energy transfer in photovoltaic molecular aggregates.
Ultrafast charge transfer and interlayer exciton formation in WSe2/WS2 and WSe2/graphene heterostructures
Authors: Yu Yang , Xing Xiao , Zhang Wenjie , Liu Weimin , Ma Guohong
Published: February 2021

The ultrafast charge transfer and dynamical interlayer excitons were investigated in the heterostructures comprising WSe2/WS2 and WSe2/graphene bilayer. The results reveal the stacking order affect the charge transfer and therefore the formation of exciton in the heterostructure significantly.
Conditioned thermal states as nonclassical gates in subcycle sampling of quantum fields
Authors: Cusson Patrick , Virally Stéphane , Seletskiy Denis V.
Published: February 2021

Time-domain quantum electrodynamics is coming of age with recent demonstrations of direct probing of femtosecond quantum fields. Here, we propose to harness nonclassical light from bright entangled sources to dramatically enhance field-resolved measurements.
Phase-Modulated Rapid-Scanning Fluorescence-Detected Two-Dimensional Electronic Spectroscopy
Authors: Agathangelou Damianos , Javed Ariba , Joffre Manuel , Ogilvie Jennifer P.
Published: February 2021

We demonstrate a rapid-scanning approach for fluorescence-detected two-dimensional electronic spectroscopy based on phase modulation and digital lock-in detection. The complex linear and non-linear signals of interest are retrieved simultaneously within several seconds of acquisition time.
Disentangling genuine dynamics from cross phase modulation artefacts in Femtosecond Stimulated Raman Spectroscopy
Authors: Batignani Giovanni , Ferrante Carino , Fumero Giuseppe , Scopigno Tullio
Published: February 2021

Coherent artefact is a well-known nonlinear process plaguing ultrafast time-resolved experiments. Here, a Femtosecond-Stimulated-Raman-Scattering based approach, able to disentangle genuine dynamics from coherent artefacts, is introduced for demonstrating optically-driven femtosecond enhancement of the exchange interaction. © 2020 The Author(s)
Effects of the Pump Wavelength on Laser-Induced Ultrafast Demagnetization
Authors: Légaré Katherine , Cardin Vincent , Balčiūnas Tadas , Baltuška Andrius , Ibrahim Heide , Jal Emmanuelle , Vodungbo Boris , Jaouen Nicolas , Varin Charles , Lüning Jan , Légaré François
Published: February 2021

A high harmonics source is used to perform x-ray resonant magnetic scattering on magnetic samples. The dynamics of laser-induced ultrafast demagnetization are probed and longer pump wavelengths are found to increase the initial quenching levels.
Observation of Laser-Assisted (e,2e) in Ultrashort Intense Laser Fields
Authors: Hiroi Takashi , Morimoto Yuya , Kanya Reika , Yamanouchi Kaoru
Published: February 2021

We observed one-photon energy exchange process of laser-assisted electron impact ionization of argon in intense laser fields, and the increase of the signal intensity due to light-dressing effect was revealed.
Second harmonic generation driven by petahertz non-linear current in a centrosymmetric organic superconductor
Authors: Kawakami Yohei , Amano Tatsuya , Ohashi Hirozumi , Itoh Hirotake , Sasaki Takahiko , Yonemitsu Kenji , Iwai Shinichiro
Published: February 2021

A non-linear petahertz current driven by a single-cycle 6 femtosecond field shows up as SHG in a centrosymmetric organic superconductor. The SHG represents a CEP sensitive nature and an enhancement near the superconducting temperature.
Role of band structure on solid-state high-order harmonic generation
Authors: Lin Long , Li Peng-Cheng , Chu Shih-I
Published: February 2021

Electric currents in condensed-matter systems driven by the intense laser fields are opening new frontiers in petahertz electronics. However, new challenges are arising as the role of band structure in solid-state high-order harmonic generation (SHHG) has yet to be resolved. Here, we adopt a derivative-free unconstrained optimization algorithm to optimize the band structure for the SHHG, and investigate the sensitivity of the SHHG to the band structure of the solid by using a single-band model. We find that the band structure play an important role in SHHG.
Ultrafast spectroscopy of transparent dye-sensitized solar cells designed for the near-infrared
Authors: NIKOLINAKOS Ilias , NAIM Waad , NOVELLI Vittoria , BARBERO Nadia , DZEBA Iva , GRIFONI Fionnuala , BAROLO Claudia , SAUVAGE Frédéric , HAACKE Stefan
Published: February 2021

We report here femtosecond transient absorption studies of a novel cyanine derivative near-IR absorbing dye incorporated in transparent solar cell devices of record efficiency, revealing dye-aggregation as the main injection yield limiting factor.
Atto-FTH – Fourier Transform Holography Beyond the Temporal Coherence Limit
Authors: Wang Sici , Eschen Wilhelm , Liu Chang , Steinert Michael , Pertsch Thomas , Limpert Jens , Rothhardt Jan
Published: February 2021

We present a lensless imaging method which allows combining high temporal and high spatial resolution. We demonstrate a spatial resolution of 38 nm with an XUV bandwidth supporting 320 as pulse duration.
Field-resolved response of mid-infrared plasmonic antennas
Authors: Fischer M. P. , Maccaferri N. , Gallacher K. , Frigerio J. , Pellegrini G. , Isella G. , Leitenstorfer A. , Paul D. J. , Biagioni P. , Brida D.
Published: February 2021

We introduce a new experimental strategy to investigate the transient resonant behavior of plasmonic nanostructures. Our approach allows to access their full-time field-resolved response in amplitude and phase.
Ultrafast Dynamics of Singlet Excitons in Perylene Derivative Nanoparticles
Authors: Rehhagen Chris , Rafiq Shanawaz , Scholes Gregory D. , Lochbrunner Stefan
Published: February 2021

The ultrafast exciton dynamics of Perylene Red nanoparticles is investigated by transient absorption spectroscopy. The singlet exciton moves incoherently in the nanoparticle with a diffusion constant of 0.22nm2/ps till it decays into a dark state within 85 ps.
Study of Molecular Ionization and Dissociation with a Strong Field Autocorrelator
Authors: Hu Hongtao , Kangaparambil Sarayoo , Hanus Václav , Dorner-Kirchner Martin , Baltuška Andrius , Kitzler-Zeiler Markus , Xie Xinhua
Published: February 2021

We present strong field autocorrelation measurements of molecular ionization and dissociation with a reaction microscope. Time-frequency analysis of the time-domain signals was performed to obtain electron and nuclear dynamics during molecular ionization and dissociation.
Oscillatory Dynamics of the Spin-Boson Model with Ultrastrong Interactions with the Environment
Authors: Acharyya Nirmalendu , Richter Martin , Fingerhut Benjamin P.
Published: February 2021

We numerically investigate the impact of non-diagonal system-bath interaction on real-time dissipative dynamics of the Spin-Boson model. For Ohmic environments, a novel class of coherences emerges that induce longtime entanglement between system and environment.
Role of the bound states in below-threshold harmonic generation of Cs atom
Authors: Wang Zhi-Bin , Guo Chun-Xiang , Jiao Zhi-Hong , Li Peng-Cheng , Chu Shih-I
Published: February 2021

We present an ab initio investigation of below-threshold harmonic generation (BTHG) of Cs atom in intense mid-infrared laser fields by accurately solving the time-dependent Schrödinger equation. We find that the spectra yield in BTHG of Cs atom dependents on the light intensity in the multiphoton ionization regime, and the bound states play an important role in the channel selection process for BTHG. Combining with wavelet time-frequency transform, semiclassical trajectories simulation, and quantum channel analysis, the dynamical origin of the BTHG is uncovered.
Forward and Backward Emission of Two-Photon Laser Induced Fluorescence
Authors: Wang Kai , Wang Yejun , Wang Jizhou , Yi Zhenhuan , Shen Yujie , Kulatilaka Waruna D. , Sokolov Alexei V. , Scully Marlan O.
Published: February 2021

Two-photon laser induced fluorescence (TPLIF) in Kr is studied using femtosecond pump-probe technique. Forward and backward radiations have shown different behaviors, which implicate the different physical process for TPLIF in forward and backward direction.
Nonlinear plasmonic response in GaAs/InGaAs core/shell nanowires
Authors: Rana Rakesh , Balaghi Leila , Fotev Ivan , Schneider Harald , Helm Manfred , Dimakis Emmanouil , Pashkin Alexej
Published: February 2021

We show nonlinear plasmonic response in GaAs/In0.2Ga0.8As nanowires using high-field terahertz pulses. With increasing THz field, plasmon resonance redshifts and its spectral weight decreases indicating a spatially inhomogeneous intervalley electron scattering.
Optics-Free Focusing and Application to Spectral Filtering of XUV Beam
Authors: Valentin C. , Veyrinas K. , Vabék J. , Descamps D. , Péjot C. , Burgy F. , Catoire F. , Constant E. , Mével E.
Published: February 2021

We experimentally characterize XUV intensity profiles and wavefronts, and demonstrate XUV beams focusing without resorting any optics. We use this coherent effect to spectrally filter group of harmonics. Simulations show possible control of attosecond temporal structure.
Controlling the Dimensionality of Exciton-Exciton Annihilation in Atomically Thin Black Phosphorus
Authors: Pareek Vivek , Madéo Julien , Dani Keshav M.
Published: February 2021

We use micro-transient absorption spectroscopy to show that the exciton-exciton annihilation process in bilayer black phosphorus can be tuned from 1D- to 2D-like in nature by controlling initial exciton density and temperature.
High-order phase measurements of attosecond wave packets
Authors: Fuchs Jaco , Douguet Nicolas , Donsa Stefan , Martin Fernando , Burgdörfer Joachim , Argenti Luca , Cattaneo Laura , Keller Ursula
Published: February 2021

We demonstrate that the beating between 1- and 2-photon-transitions enables a sensitive detection of high-order phase terms of electron wave packets. This allows us to observe phase features well beyond the capabilities of existing attosecond spectroscopy.
Characterization of Attosecond Pulse Train and Nonlinear Fourier Transform Spectroscopy in Dissociative Ionization of Acetylene
Authors: Matsubara Takuya , Fukahori Shinichi , Nabekawa Yasuo , Yamanouchi Kaoru , Midorikawa Katsumi
Published: February 2021

An attosecond pulse train consisting of ~210 as pulses is characterized by interferometric autocorrelation measurements of dissociative ionization of C2H2. The selective C-C bond breaking of C2H2+ by the 7th harmonic is identified.
Near-Fully Efficient, Back-Conversion Suppressed OPA and Efficient Upconversion of Fractional Harmonics
Authors: Flemens Noah , Swenson Nicolas , Moses Jeffrey
Published: February 2021

We show simultaneous phase matching of OPA and idler SHG suppresses back-conversion in OPA. Spatiotemporal analysis of LNB-based devices demonstrates femtosecond pulse amplification with 45% signal energy efficiency and efficient fractional-harmonic upconversion of the pump.
Generation of a Femtosecond Optical Vortex at ~ 2 µm
Authors: Zhao Yongguang , Wang Li , Chen Weidong , Xu Xiaodong , Loiko Pavel , Mateos Xavier , Wang Zhengping , Xu Xinguang , Griebner Uwe , Petrov Valentin
Published: February 2021

A mode-locked solid-state laser in combination with a single-cylindrical-lens mode-converter is employed to produce a femtosecond optical vortex. The bandwidth-limited 112-fs pulses represent the shortest duration for a vortex laser in the 2-µm spectral range.
Simultaneous Measurement of Two Femtosecond Pulses and Interpulse Delay for Two-colour Pump-probe Experiments
Authors: Miranda Miguel , Pettipher Allan , Canhota Miguel , Romero Rosa , Crespo Helder , Tisch John
Published: February 2021

We numerically demonstrate the simultaneous measurement of the complete temporal profile and interpulse delay of two few-cycle 10-fs laser pulses with different wavelengths using a single dispersion scan measurement.
Experimental quantification of pulse train instabilities using dispersion scan
Authors: Alonso Benjamín , Torres-Peiró Salvador , Romero Rosa , Guerreiro Paulo T. , Almagro-Ruiz Azahara , Muñoz-Marco Héctor , Pérez-Millán Pere , Crespo Helder
Published: February 2021

We apply the self-calibrating d-scan technique to quantify the pulse train instabilities in a fiber laser with supercontinuum generation in a photonic crystal fiber (PCF). Using an all-normal dispersion PCF, stable 15-fs pulses are measured.
Proposed Approach Based on Optical Parametric Amplification at Critical Wavelength Degeneracy for the Development of 100-PW Class Femtosecond Lasers
Authors: Dabu Razvan
Published: February 2021

At signal critical wavelength, super-broad parametric gain bandwidths can be obtained in nonlinear crystals pumped at degeneracy. Large-size partially deuterated KDP crystals, pumped by green lasers, can amplify ~1.1-μm central wavelength, sub-10 femtosecond laser pulses.
Proposal for Generating Pairs of Synchronized Ultrafast Electron Bunches
Authors: Pelchat-Voyer S. , Piché M.
Published: February 2021

We show using test-particle simulations that the method of direct-field acceleration could be used to generate pairs of synchronized electron bunches from low-density gases or micrometric targets.
Relaxation of complex electronic resonances in molecules controlled by shaped laser pulses
Authors: Granados Camilo , Mayer Nicola , Ikonnikov Evgenii , Kornilov Oleg
Published: February 2021

Relaxation of complex resonances studied in our recent work on XUV-NIR pump-probe spectroscopy of N2 and naphthalene is affected by quantum interferences. Here were explore control of the relaxation by shaped NIR pulses.