bluuebunny/crossref_metadata_2025 huggingface dataset:
Fabrication of a dual-emitting dye-encapsulated metal–organic framework as a stable fluorescent sensor for metal ion detection
Authors: Zhang Ningzi , Zhang Diwei , Zhao Jing , Xia Zhiguo
Published: April 2019

The encapsulation of fluorescein dye into porous zinc–adenine metal–organic framework (bio-MOF-1) crystals has been studied for metal cation sensing.
Cocatalyst or substrate? Competitive Fenton transformation of cysteine and salicylic acid
Authors: Tang Daojian , Zhang Guishui , Chen Fengxia , Ma Jiahai
Published: April 2019

Cysteine which acts as a cocatalyst enhanced the competitive Fenton transformation of salicylic acid.
Lanthanide f7 metalloxenes – a class of intrinsic 2D ferromagnets
Authors: Tokmachev Andrey M. , Averyanov Dmitry V. , Taldenkov Alexander N. , Parfenov Oleg E. , Karateev Igor A. , Sokolov Ivan S. , Storchak Vyacheslav G.
Published: April 2019

A class of intrinsic 2D ferromagnets – layered metalloxenes – is established by coupling graphene-like honeycomb networks of silicene and germanene with 2D lanthanide layers.
High-performance electrochemical nitrite sensing enabled using commercial carbon fiber cloth
Authors: Zhang Yi , Zhu Wenxin , Wang Yanhong , Ma Yiyue , Sun Jing , Li Tao , Wang Jianlong , Yue Xiaoyue , Ouyang Shaohui , Ji Yanwei
Published: April 2019

Exceptional high-performance and stable electrochemical nitrite sensing enabled using commercial carbon fiber cloth.
Carbon nanotubes as electrophysiological building blocks for a bioactive cell scaffold through biological assembly to induce osteogenesis
Authors: Qian Saibo , Yan Zhilin , Xu Yongjie , Tan Huaping , Chen Yong , Ling Zhonghua , Niu Xiaohong
Published: April 2019

Bio-functional cell scaffolds have great potential in the field of tissue regenerative medicine.
Biofunctionalization of decellularized porcine aortic valve with OPG-loaded PCL nanoparticles for anti-calcification
Authors: Li Yang , Zhang Yu , Ding Jing-Li , Liu Ji-Chun , Xu Jian-Jun , Tang Yan-Hua , Yi Ying-Ping , Xu Wei-Chang , Yu Wen-Peng , Lu Chao , Yang Wei , Yang Jue-Sheng , Gong Yi , Zhou Jian-Liang
Published: April 2019

A novel composite valve with controlled release OPG was prepared by introducing tissue engineering technology and nano drug-loading system to introduce anti-calcification biological factor OPG on the decellularized valve.
Mesoporous MnOx–CeO2 composites for NH3-SCR: the effect of preparation methods and a third dopant
Authors: Weiman Li , Haidi Liu , Yunfa Chen
Published: April 2019

In this study, an optimal oxalate route was used to obtain nickel/cobalt doped MnOx–CeO2 mixed oxides. Nickel doped MnOx–CeO2 showed excellent NH3-SCR activity and H2O + SO2 resistance.
Improvement of electric field-induced strain and energy storage density properties in lead-free BNKT-based ceramics modified by BFT doping
Authors: Jaita Pharatree , Sanjoom Ratabongkot , Lertcumfu Narumon , Rujijanagul Gobwute
Published: April 2019

The effects of Ba(Fe0.5Ta0.5)O3 additive on phase, dielectric, ferroelectric, piezoelectric, electric field-induced strain, and energy storage density of the Bi0.5(Na0.80K0.20)0.5TiO3–0.03(Ba0.70Sr0.03)TiO3 ceramics have been investigated.
Modifying morphology and defects of low-dimensional, semi-transparent perovskite thin films via solvent type
Authors: Ponchai Jitprabhat , Kaewurai Paphada , Boonthum Chirapa , Pinsuwan Kusuma , Supasai Thidarat , Sahasithiwat Somboon , Kanjanaboos Pongsakorn
Published: April 2019

Low dimensional perovskites via DMF : DMSO = 8 : 2 with potential for semi-transparent solar cell led to superior surface morphology with large crystallite size and low defects.
Tunable gap in stable arsenene nanoribbons opens the door to electronic applications
Authors: García-Fuente A. , Carrete J. , Vega A. , Gallego L. J.
Published: April 2019

Our study of arsenene nanorribons uncovers their structural diversity and, more crucially, the tunability of their electronic structure.
Polyacetylene carbon materials: facile preparation using AlCl3 catalyst and excellent electrochemical performance for supercapacitors
Authors: Luo Tianhang , Xu Xuebing , Jiang Maoqiang , Lu Ying-zhou , Meng Hong , Li Chun-xi
Published: April 2019

Polyacetylene (PA) was synthesized for the first time under mild conditions via polymerization of acetylene in n-octane with AlCl3 as a catalyst, whereby a series of PA-derived carbon materials were obtained.
Solvatochromism and pH effect on the emission of a triphenylimidazole-phenylacrylonitrile derivative: experimental and DFT studies
Authors: Anandhan Karnambaram , Cerón Margarita , Perumal Venkatesan , Ceballos Paulina , Gordillo-Guerra Paola , Pérez-Gutiérrez Enrique , Castillo Armando E. , Thamotharan Subbiah , Percino M. Judith
Published: April 2019

The optical properties of an imidazole derivative were studied at various pH values and in solvents and the solid-state through experimental and DFT calculation.
An energy-blocking nanoparticle decorated with anti-VEGF antibody to reverse chemotherapeutic drug resistance
Authors: Gu Liu-Qing , Cui Peng-Fei , Xing Lei , He Yu-Jing , Chang Xin , Zhou Tian-Jiao , Liu Yu , Li Ling , Jiang Hu-Lin
Published: April 2019

Multi-drug resistance (MDR) of tumor has greatly hindered the therapeutic effect of chemotherapeutic drugs, resulting in chemotherapy failure, and overexpression of ATP-binding cassette (ABC) transporters in cell membrane is the main cause of MDR.
The nature of the chemical bond in oxyanionic crystals based on QTAIM topological analysis of electron densities
Authors: Korabel'nikov Dmitry V. , Zhuravlev Yuriy N.
Published: April 2019

The QTAIM topological analysis of the calculated electron densities in oxyanionic crystals revealed the covalency criteria for metal–oxygen and hydrogen bonds.
Three novel polyoxometalate-based inorganic–organic hybrid materials based on 2,6-bis(1,2,4-triazol-1-yl)pyridine
Authors: Wu Yingying , Li Xuefei , Liu Ying , Xiao Ge , Huang Yijiao , Li Yamin , Dang Dongbin , Bai Yan
Published: April 2019

Three novel inorganic–organic hybrid materials based on 2,6-bis(1,2,4-triazol-1-yl)pyridine have been synthesized with different polyanions and transition metal ions.
Facile synthesis of aminated indole-based porous organic polymer for highly selective capture of CO2 by the coefficient effect of π–π-stacking and hydrogen bonding
Authors: He Qiang , Xu Yi , Yang Xiaoqiang
Published: April 2019

It was demonstrated that the coefficient effect endows POP PIN-NH2 with outstanding CO2 absorption capacity and high selectivity.
Study on the identification of Pinelliae rhizoma and Pinelliae pedatisectae rhizoma based on the characteristic component triglochinic acid
Authors: Jing Yong , Lai Yueyue , Chen Hui , Li Min , Zhou Juan , Lan Zelun
Published: April 2019

A monomeric compound, triglochinic acid, has been isolated from Pinelliae pedatisectae rhizoma with its structure analyzed using NMR. It is used as a characteristic compound to distinguish Pinelliae pedatisectae rhizoma and Pinelliae rhizoma for quality control.
Methyl-restricted rotor rotation on the stator produces high-efficiency fluorescence emission: a new strategy to achieve aggregation-induced emission
Authors: Yang Haicheng , Zhou Xinyue , Hui Tianqi , Han Yingying , Jiang Xiaonan , Yan Jie
Published: April 2019

At present, we have realized that the aggregation-induced emission (AIE) achieves the purpose of fluorescence enhancement by restricting rotations to reduce intermolecular or intramolecular energy loss.
Antiprotozoal dimeric naphthylisoquinolines, mbandakamines B3 and B4, and related 5,8′-coupled monomeric alkaloids, ikelacongolines A–D, from a Congolese Ancistrocladus liana
Authors: Mufusama Jean-Pierre , Feineis Doris , Mudogo Virima , Kaiser Marcel , Brun Reto , Bringmann Gerhard
Published: April 2019

The discovery of the two unsymmetrically coupled dimeric naphthylisoquinoline alkaloids, the mbandakamines B3 and B4, showing a high steric hindrance at the central biaryl axis and displaying pronounced antiplasmodial activities, is described.
Tough and stretchable inorganic/organic double network ion gel containing gemini-type ionic liquid as a multiple hydrogen bond cross-linker
Authors: Yasui Tomoki , Kamio Eiji , Matsuyama Hideto
Published: April 2019

The extensibility and toughness of inorganic/organic double-network ion gels were dramatically increased using gemini-type ionic liquids as a hydrogen bonding-based weak cross-linker.
Mint leaf derived carbon dots for dual analyte detection of Fe(iii) and ascorbic acid
Authors: Raveendran Varsha , Suresh Babu Adukamparai Rajukrishnan , Renuka Neeroli Kizhakayil
Published: April 2019

Highly luminescent carbon dots (CDs) are obtained from mint leaves adopting a simple and cost effective route devoid of additional chemical reagents and functionalization.
Adhesive elastocapillary force on a cantilever beam
Authors: Gilet Tristan , Gernay Sophie-Marie , Aquilante Lorenzo , Mastrangeli Massimo , Lambert Pierre
Published: April 2019

We measure the force–displacement curve of a cantilever beam in contact with a substrate and with an intervening capillary bridge. This elastocapillary equilibrium represents a physical model of the hairy adhesive pads of insects.
Unraveling the high-activity nature of Fe–N–C electrocatalysts for the oxygen reduction reaction: the extraordinary synergy between Fe–N4 and Fe4N
Authors: Ao Xiang , Zhang Wei , Li Zhishan , Lv Lin , Ruan Yunjun , Wu Hong-Hui , Chiang Wei-Hung , Wang Chundong , Liu Meilin , Zeng Xiao Cheng
Published: April 2019

Fe4N can play a decisive role in boosting the catalytic performance of Fe–N4 coordination sites.
GeSe@SnS: stacked Janus structures for overall water splitting
Authors: Yang Hongchao , Ma Yandong , Zhang Shuai , Jin Hao , Huang Baibiao , Dai Ying
Published: April 2019

A promising visible-light photocatalyst with an intrinsic dipole consisting of GeSe and SnS.
Highly compressible zinc-ion batteries with stable performance
Authors: Cao Hongmei , Wan Fang , Zhang Linlin , Dai Xi , Huang Shuo , Liu Lili , Niu Zhiqiang
Published: April 2019

The compressible ZIBs can be compressed arbitrarily under 60% strain and they exhibit stable electrochemical performance under different compressive strains.
Benzo[1,2-b:4,5-b′]diselenophene-fused nonfullerene acceptors with alternative aromatic ring-based and monochlorinated end groups: a new synergistic strategy to simultaneously achieve highly efficient organic solar cells with the energy loss of 0.49 eV
Authors: Wan Shi-Sheng , Xu Xiaopeng , Wang Jin-Liang , Yuan Gui-Zhou , Jiang Zhao , Ge Gao-Yang , Bai Hai-Rui , Li Zheng , Peng Qiang
Published: April 2019

The PCE of 13.68% with the Eloss of 0.49 eV were obtained, which were the highest values obtained to date in binary PSCs with monochlorinated NF-SMAs.
Photo-crosslinked coatings based on 2-hydroxypropyl acrylamide for the prevention of biofouling
Authors: Yoshikawa Chiaki , Delalat Bahman , Huang Fei , Braun Susanne , Nishijima Nanami , Voelcker Nicolas H. , Kingshott Peter , Thissen Helmut
Published: April 2019

We have developed a simple and versatile polymer coating method that provides excellent non-biofouling properties.
Influence of surface chemistry on the formation of a protein corona on nanodiamonds
Authors: Garcia-Bennett Alfonso E. , Everest-Dass Arun , Moroni Irene , Rastogi Ishan Das , Parker Lindsay M. , Packer Nicolle H. , Brown Louise J.
Published: April 2019

The protein corona of nanodiamonds is dominated by low molecular weight proteins and is largely independent of surface chemistry. The pre-incubation of nanodiamonds in serum and the formation of a protein corona decrease the production of reactive oxygen species, increasing the cell viability of macrophages.
A DFT study of the electronic, optical and topological properties of free and biaxially strained CuIn1−xAlxSe2
Authors: Jiang Pingping , Boulet Pascal , Record Marie-Christine
Published: April 2019

Among the CuIn1−xAlxSe2alloys, that withx= 0.25 is the optimal one in terms of band gap and conversion efficiency. Its absorption coefficient is highly modified under biaxial strains that occur in thin films.
Solid-state silicon nanoparticles with color-tunable photoluminescence and multifunctional applications
Authors: Gong Ting , Li Yanjuan , Lei Bingfu , Zhang Xuejie , Liu Yingliang , Zhang Haoran
Published: April 2019

A facile hydrothermal route was proposed to synthesize a bright blue-emitting solution of silicon nanoparticles (s-Si NPs) with a high photoluminescence quantum yield (PLQY) of 66%, and multifunctional applications has been proposed.
A laminar MAPbBr3/MAPbBr3−xIx graded heterojunction single crystal for enhancing charge extraction and optoelectronic performance
Authors: Li Wen-Guang , Wang Xu-Dong , Liao Jin-Feng , Wei Ze-Feng , Xu Yang-Fan , Chen Hong-Yan , Kuang Dai-Bin
Published: April 2019

A laminar MAPbBr3/MAPbBr3−xIx graded heterojunction single crystal forms a graded valence band structure, resulting in enhanced hole extraction as well as superior photodetection performance.
Multichannel photoluminescence tuning in Eu-doped apatite phosphors via coexisting cation substitution, energy transfer and valence mixing
Authors: Dang Peipei , Li Guogang , Liang Sisi , Lian Hongzhou , Lin Jun
Published: April 2019

Multichannel color tuning from blue-and-green to yellow-and-red was achieved by coexisting crystal field regulation of Sr2+/Ca2+ substitution, designing Eu2+ → Mn2+ energy transfer and mixing valence of Eu2+/Eu3+.
Anharmonic lattice dynamics of Te and its counter-intuitive strain dependent lattice thermal conductivity
Authors: Li Shasha , Ma Jie , Pei Yanzhong , Chen Yue
Published: April 2019

The lattice thermal conductivity of Te is found to show counter-intuitive strain dependence under uniaxial strains.
Tris‐(8‐hydroxyquinoline) aluminium thin film as saturable absorber for passively Q‐switched erbium‐doped fibre laser
Authors: Salam Sameer , Harun Sulaiman W. , Al‐Masoodi Ahmad H. H. , Ahmed Mahmoud H. M. , Al‐Masoodi Ab H.H. , Alani Ibrahim A. M. , Abd. Majid Wan H. , Wong Wei Ru , Yasin Moh
Published: April 2019

A passively Q‐switched erbium‐doped fibre laser was demonstrated by using tris‐(8‐hydroxyquinoline)aluminium (Alq3) organic material as a passive saturable absorber (SA). The SA was fabricated by a drop casting technique at room temperature and incorporated into a laser cavity by inserting it between two optical fibre ferrules. The Q‐switched fibre laser operates at a centre wavelength of 1559 nm with a full‐width half maximum of 1 nm. The generated pulse train is stable and has a pulse width decreased from 6.65 to 1.2 µs and the pulse repetition rate increased from 31.65 to 144.5 kHz as the pump power increased from 20 to 122 mW. The maximum pulse energy obtained is 63.89 nJ. This work indicates that the Alq3 as SA has a great potential to be utilised for pulsed laser generation. To the best of the authors' knowledge, this is the first time an organic material is utilised as a SA device for generating a stable Q‐switched laser pulse.
Novel islanding detection method for inverter‐based distributed generators based on adaptive reactive power control
Authors: Chen Xiaolong , Wang Xinyi , Jian Jie , Tan Zhiyao , Li Yongli , Crossley Peter
Published: April 2019

Here, a novel active islanding detection method for inverter‐based distributed generators (IBDGs) is presented. In order to reduce the disturbance in grid‐connected mode and realise rapid and effective detection during islanding, the linear reactive power disturbance is utilised in the proposed method and its slope can change adaptively. The voltage variation and correlation factor between reactive power disturbance and frequency variation are proposed as criteria for disturbance slope adjustment. In addition, considering IBDGs located at different positions can detect the same frequency variation characteristics, the value of the frequency is used as the criteria to control the disturbance values, which can guarantee the synchronisation of disturbances added on different IBDGs without the need of communication. According to the anti‐islanding test system recommended in IEEE Std.929‐2000, the effectiveness of the method has been validated with several case studies in the power systems computer‐aided design (PSCAD)/EMTDC environment.
Benefits of the CI‐CCS converter
Authors: Nathan Kumaran S. , Ghosh Saikat S. , Tripathi Prabhat R. , Siwakoti Yam P. , Flack Timothy J. , Li Xinru , Long Teng
Published: April 2019

An enhanced DC–DC converter is proposed in this paper, based on the combination of the Cuk converter and single‐ended primary‐inductor converter (SEPIC). This converter uses a single switching node which is common to both Cuk and SEPIC energy transfer stages. The converter uses only one switch, yet provides dual outputs in the form of a bipolar DC bus with a common ground. Since the switch is grounded, a simple, non‐isolated gate driver may be used. The proposed converter uses integrated magnetic cores to couple the input and output inductors, which significantly reduces the input current ripple. The new converter is referred to as the Coupled‐Inductors Combined Cuk‐SEPIC (CI‐CCS) converter.
Investigation on filter requirements and stability effects of SiC MOSFET‐based high‐frequency grid‐connected converters
Authors: John Blessy , Ghosh Arindam , Zare Firuz
Published: April 2019

The new era of power semiconductor devices is exploiting the high potential of wide bandgap device‐based high‐frequency power converters. The advanced capabilities of Silicon carbide (SiC) semiconductors allow the power converters to switch at higher switching frequencies with lower switching and conduction losses. Operation under higher switching frequencies can drastically reduce the output filter requirements in grid‐connected converters. At higher frequencies, an L‐type filter can sufficiently eliminate the switching frequency harmonics. This will reduce the size and cost of the filter, which eventually results in the optimised system cost. In this paper, the filter requirements of SiC based high‐frequency converters are investigated. Usage of LCL filters to remove high‐frequency harmonic will shift the resonance frequency to high‐frequency region, where these harmonics can create electromagnetic compatibility issues. In industries, passive damping is utilised for mitigating these oscillations. This will result in additional losses and compromise the advantages of SiC devices. Even though active damping can be utilised to eliminate resonance oscillations, the high bandwidth processors and measurement devices may increase the cost further. Simulation study is conducted on PSCAD/MATLAB and the experimental verification using Cree SiC devices verify the filter requirements, stability issues, and possible mitigating solutions for high‐frequency grid converters.
Assessment of the impact of MMC‐VSC intrinsic energy on power system stability
Authors: Fradley John , Preece Robin , Barnes Mike
Published: April 2019

Synchronous generation is being displaced by renewable energy sources and high‐voltage direct current (HVDC) interconnectors. These factors will lead to a diminishing provision of ancillary services. Conventional services tendered to provide network support rely on the availability of synchronous generation and because of this, future power system operators will have to develop new ways to obtain the ancillary services required. A technology rapidly gaining in popularity is voltage source converter (VSC)‐based HVDC and further advances in the technology have led to the modular multilevel converter (MMC). Due to the design of an MMC there is intrinsic electrostatic energy that could potentially be utilised to provide ancillary services. This study determines the electrostatic energy available from a typical grid‐scale MMC VSC for network support during disturbances and for power oscillation damping. Supporting simulations are provided to ascertain the impact that this electrostatic energy could have on network performance if utilised. This study displays that although an MMC possesses intrinsic energy, utilising it for frequency response would provide negligible system benefits. However, for POD, the available intrinsic MMC energy did improve system stability which leads to the potential of using multiple MMCs to increase the energy and further improve system stability.
Extreme environment interconnects and packaging for power electronics
Authors: Campos‐Zatarain Alberto , Hinton Jack , Mirgkizoudi Maria , Li Jing , Harris Russell , Kay Robert W. , Flynn David
Published: April 2019

This paper presents the combination of an innovative assembly and packaging process utilising solid liquid inter diffusion (SLID) Cu‐Sn interconnects within bespoke ceramic substrates that have been produced using additive manufacturing (AM). The resultant process chain supports the integration and packaging of power electronics for harsh environment applications. Here, the authors explore how the bond strength and composition of Cu‐Sn SLID interconnects vary during exposure to thermal‐mechanical load profiles. Samples of Cu‐Sn are exposed to thermal loading up to 300°C and integrated mechanical loading via high random frequency vibrations (1 and 2000 Hz). In parallel, micro‐extrusion printing methods in which high‐viscosity ceramic pastes are dispensed through cylindrical fine nozzles (2–250 µm) using CNC‐controlled motion has enabled complex 3D geometries to be fabricated. Additional secondary conductor deposition after firing the ceramic substrate enables the electronic circuitry to be generated without dedicated tooling, masks, or templates. This work presents the first fully 3D‐printed ceramic‐based electronic substrates. To demonstrate the applications of this printing method, a 555 timer circuit with flashing LED has been printed and the components surface mount assembled. The resultant ceramic substrates are dense, mechanically robust, and the reflowed circuit functions exactly as intended.
Phase voltage distortion of IPM and SPM machines with distributed windings in field weakening region
Authors: Zhao Nan , Schofield Nigel , Hu Yiheng
Published: April 2019

This study investigates the field‐weakening capability of interior permanent magnet (IPM) and surface‐mounted permanent magnet (SPM) machines with distributed windings by considering phase voltage distortion in field‐weakening region. For analysis and comparison, the Nissan Leaf vehicle traction machine is studied as a reference benchmark machine and then a comparable SPM machine is designed within the main constraints of the benchmark machine. A finite element analysis model of the benchmark machine is developed and validated by published experimental measurement. Sinusoidal phase current is desired to enhance machine torque performance and power electronic converters employing vector control method are commonly used for traction machine supply. However, the machine terminal phase voltage distortion may introduce additional difficulties for machine control. Therefore, firstly, phase voltage distortions of IPM and SPM machines with distributed windings are compared and the mechanisms are discussed. Due to the voltage distortion, the peak value of phase voltage may be higher than the fundamental one. Therefore, the influences of IPM and SPM topologies on machine traction characteristics are investigated. The study indicates that SPM machines with distributed windings can be designed to achieve comparable torque and power performance and better field‐weakening capability compared to IPM machines.
Linearizing Nonlinear Optics
Authors: Bruno E. Schmidt , Lassonde Philippe , Ernotte Guilmot , Clerici Matteo , Morandotti Roberto , Ibrahim Heide , Légaré François
Published: April 2019

Fourier nonlinear optics merges the simplicity of linear optics with the power of nonlinear optics to achieve a decoupling of frequencies, amplitudes and phases in nonlinear processes - enabling first deep UV shaping at 207nm.
Segmented Terahertz device for ultrashort electron acceleration, compression, focusing and streaking
Authors: Zhang Dongfang , Fallahi Arya , Hemmer Michael , Wu Xiaojun , Fakhari Moein , Hua Yi , Cankaya Huseyin , Calendron Anne-Laure , Zapata Luis E. , Matlis Nicholas H. , Kärtner Franz X.
Published: April 2019

We present a segmented THz based device (STEAM) capable of performing multiple high-field operations on the 6D-phase-space of ultrashort electron bunches. With this single device, powered by few-micro-Joule, single-cycle, 0.3 THz pulses, we demonstrate record THz-acceleration of >30 keV, streaking with <10 fs resolution, focusing with >2 kT/m strength, compression to ~100 fs. The STEAM device can be fabricated with regular mechanical machining tools and supports real-time switching between different modes of operation. It paves the way for the development of THz-based compact electron guns, accelerators, ultrafast electron diffractometers and Free-Electron Lasers.
Multi-mJ terahertz generation in periodically poled Lithium-Niobate by pulse recycling with dispersion compensation
Authors: Wang Lu , Fallahi Arya , Ravi Koustuban , Kä;rtner Franz
Published: April 2019

We propose a design for high efficiency narrow-band terahertz generation using multiple stages with dispersion compensation. Terahertz efficiencies of a few percent are predicted.
Spectrally resolved wavefront characterization of broadband ultrafast high-harmonic pulses
Authors: G.S.M. Jansen , L. Freisem , D. Rudolf , K.S.E. Eikema , S. Witte
Published: April 2019

We demonstrate a sensor that measures wavefronts of multiple extreme ultraviolet wavelengths simultaneously. By incorporating transmission gratings into the apertures of a Hartmann mask, we can record wavefront information for series of discrete harmonics from a high-harmonic generation source in a single camera exposure, without the need for scanning parts. Wavefronts of up to nine high harmonics at 25-49 nm wavelength are retrieved, and ultrafast spatiotemporal couplings can be detected.
Dual Self-Diffraction Dispersion-scan for Measuring Spatially Inhomogeneous Ultrashort Pulses
Authors: Canhota Miguel , Weigand Rosa , Crespo Helder
Published: April 2019

We develop a self-diffraction dispersion-scan method that simultaneously measures two distinct spatial portions of an ultrashort light pulse and apply it to the temporal characterization of 400-nm broadband ultraviolet pulses generated by multi-plate continuum.
HHG probing of atomic dipoles by electronic wave-packet caustics
Authors: Faccialà Davide , Pabst Stefan , Bruner Barry D. , Ciriolo Anna G. , Devetta Michele , Negro Matteo , Soifer Hadas , Dudovich Nirit , Stagira Salvatore , Vozzi Caterina
Published: April 2019

We exploit high-order harmonic generation spectroscopy at the caustics of the recombining electron wave-packet as a method for directly comparing experimental spectra with ab-initio theories. Experimental results in xenon and comparison with ab-initio time-dependent configuration-interaction singles calculations allowed to assess the role of the wave-packet enhancement during the giant resonance. Results in argon show that this technique can also be applied to other targets.
High-order Harmonic Field Retrieval in Ethylene
Authors: Makhija Varun , Tross Jan , Kumarappan Vinod , Spanner Michael , Vozzi Caterina , Trallero Carlos , Stagira Salvatore
Published: April 2019

The XUV field emitted by impulsively aligned ethylene molecules during high-order harmonic generation is retrieved as a function of molecular orientation. The results can be ascribed to multielectron contributions to the harmonic emission.
Single shot XUV nanoimaging using an intense femtosecond soft X-ray laser
Authors: Zürch Michael , Tuitje Frederik , Helk Tobias , Gautier Julian , Tissandier Fabian , Goddet Jean-Philippe , Guggenmos Alexander , Kleineberg Ulf , Sebban Stephane , Spielmann Christian
Published: April 2019

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.
High-order harmonic generation in femtosecond laser micromachined devices
Authors: Ciriolo Anna G. , Martínez Vázquez Rebeca , Crippa Gabriele , Faccialà Davide , Negro Matteo , Devetta Michele , Pereira Lopes Diogo , Pusala Aditya , Vozzi Caterina , Osellame Roberto , Stagira Salvatore
Published: April 2019

We demonstrate the generation of high-order harmonics in a fused-silica device fabricated through femtosecond laser micromachining. This achievement paves the way for the miniaturization of HHG applications from large-scale laboratories to microstructures.
Generation and complete temporal characterization of 5-fs EUV pulses
Authors: Lucchini Matteo , Lucarelli Giacinto D. , Murari Mario , Trabattoni Andrea , Fabris Nicola , Frassetto Fabio , De Silvestri Sandro , Poletto Luca , Nisoli Mauro
Published: April 2019

Extreme-ultraviolet pulses as short as 5 fs, produced by high-order harmonic generation and selected by a time-delay compensated monochromator, were fully reconstructed thanks to an advanced ptychographic technique, while most commonly used reconstruction methods fail. These pulses constitute the shortest extreme ultraviolet pulses ever achieved via a time-delay compensated monochromator.
Multiscale temporal probing of elemental ultrafast magnetization dynamics in permalloy using High order Harmonics
Authors: M. Barthelemy , A. Maghraoui , G. Versini , M. Vomir , J.-Y. Bigot
Published: April 2019

Chemically selective magnetization dynamics is probed in Ni8()Fe20 with High order Harmonics over a large temporal scale. It is shown that the ratio between effective exchange interaction constants of each element can be retrieved experimentally.
Electric dipole oscillation in solids characterized by Fourier transform extreme ultraviolet attosecond spectroscopy
Authors: Chisuga Yuta , Mashiko Hiroki , Oguri Katsuya , Katayama Ikufumi , Takeda Jun , Gotoh Hideki
Published: April 2019

We characterized electronic dipole oscillations in chromium doped sapphire (Cr:Al2O3) using Fourier transform extreme ultraviolet attosecond spectroscopy (FTXUV) combined with an isolated attosecond pulse, which reveals the electric band-structure and dephasing process in solids.
Coherent transition radiation from attosecond electron pulses
Authors: Tsarev Maxim , Baum Peter
Published: April 2019

We show theoretically and by simulations how coherent transition radiation from tilted surfaces can be used for characterization of attosecond free-electron pulses such as used for pump-probe electron microscopy and diffraction. The tilted geometries eliminate velocity-mismatch and beam-diameter effects, providing sensitivity to attosecond times even for almost arbitrarily large beam diameters.
All-optical switching and real-time spectroscopy of soliton molecules in a few-cycle laser oscillator
Authors: Kurtz Felix , Solli Daniel , Mali Bahram , Ropers Claus , Herink Georg
Published: April 2019

Bound states of femtosecond solitons are generated and controlled in a commercial sub-10 fs Kerr-lens mode-locked ultrashort oscillator. Using real-time time-stretch interferometry, we resolve the resonance of vibrating soliton molecules and demonstrate all-optical switching between stable bound-states of different binding distance.
High-resolution mass spectrometry and velocity map imaging for ultrafast electron dynamics in complex biomolecules
Authors: Månsson Erik P. , Wanie Vincent , Galli Mara , Castrovilli Mattea C. , Frassetto Fabio , Poletto Luca , Nisoli Mauro , Calegari Francesca
Published: April 2019

We present a design combining a velocity map imaging electron spectrometer with a reflectron mass spectrometer. Since the two spectrometer sides have different intrinsic requirements for the electric field in the central region, a large number of electrodes and a reflectron-geometry of the mass spectrometer were employed to achieve simultaneous high resolutions. Together with femtosecond and attosecond pump-probe methods it will enable studies of ultrafast dynamics in large molecular systems.
Multi-dimensional coherent spectroscopy of CdSe colloidal quantum dots at cryogenic temperatures
Authors: Liu Albert , Almeida Diogo B. , Bae Wan Ki , Padilha Lazaro A. , Cundiff Steven T.
Published: April 2019

One-quantum and zero-quantum multi-dimensional coherent spectroscopy are used to study CdSe colloidal quantum dots at cryogenic temperatures. Each technique reveals unique aspects of the electron-phonon coupling dynamics in the material.
Shaper-based infrared spectroscopy in a nonlinear Raman setup
Authors: Müller Niklas , Brückner Lukas , Motzkus Marcus
Published: April 2019

We present combined mid-infrared and nonlinear Raman spectroscopy in a single beam setup through the flexible control by sub 10 fs pulse shaping. Hence tuneable (>2000 cm-1), narrowband (<20 cm-1) infrared light is generated.
Optical pump – THz probe response of VO2 under high pressure
Authors: Braun Johannes M. , Schneider Harald , Helm Manfred , Mirek Rafał , Boatner Lynn A. , Marvel Robert E. , Haglund Richard F. , Pashkin Alexej
Published: April 2019

We present the ultrafast THz response of VO2 under high pressures. A clear anomaly is observed around 8 GPa indicating a pressure-induced phase transition. Our observations can be interpreted in terms of a bandwidth-controlled Mott-Hubbard transition.
Observation of counterion effects and dimensionality reduction in single-crystal (EDO-TTF)2SbF6 with ultrafast electron diffraction
Authors: Liu Lai Chung , Jiang Yifeng , Mueller-Werkmeister Henrike M. , Lu Cheng , Moriena Gustavo , Ishikawa Manabu , Nakano Yoshiaki , Yamochi Hideki , Miller R. J. Dwayne
Published: April 2019

Femtosecond electron diffraction is used to resolve structural dynamics in single-crystal (EDO-TTF)2XF6 (X = P, Sb). The retarded and lower-dimensional dynamics of the latter illustrate the dominant role of counterion motion in stabilizing electron transfer.
Combining time-resolved optical (TOS), electronic (trARPES) and structural (UED) probes on the class of rare earth tritellurides RTe3
Authors: Rohwer Timm , Zong Alfred , Kogar Anshul , Bie Ya-Qing , Lee Changmin , Baldini Edoardo , Ergecen Emre , Yilmaz Mehmet B. , Freelon Byron , Sie Edbert J. , Zhou Hengyun , Straquadine Joshua , Walmsley Philip , Dolgirev Pavel E. , Rozhkov Alexander V. , Fisher Ian R. , Jarillo-Herrero Pablo , Fine Boris V. , Gedik Nuh
Published: April 2019

The combination of EUV based time-resolved Angle-Resolved-Photo-Electron-Spectroscopy (trARPES), Ultrafast-Electron-Diffraction (UED) and Transient-Optical-Spectroscopy (TOS) facilitates a comprehensive study and all-embracing analysis of correlated dynamics, exemplified on the system of Charge-Density-Waves (CDW’s) in rare earth tritellurides (RTe3).
Graphite-like dynamical behaviour of graphite oxide
Authors: Shinde Amul , Testud Christoph , Adamczyk Katrin , Ruppert Matthias , Huse Nils
Published: April 2019

We report two-colour pump-probe spectroscopy of coupled structural and electronic dynamics of graphite oxide probed with 6-pm and THz pulses upon femtosecond IR excitation.
Ultrafast carrier generation in Bi1-xSbx thin films induced by intense monocycle terahertz pulses
Authors: Katayama Ikufumi , Kawakami Hiroki , Araki Kotaro , Arashida Yusuke , Minami Yasuo , Nien Lie-Wei , Handegard Orjan Sele , Nagao Tadaaki , Kitajima Masahiro , Takeda Jun
Published: April 2019

Using terahertz-pump and terahertz-probe spectroscopy, we investigated terahertz-induced carrier generation processes in Bi1-xSbx thin films. The field dependence of the terahertz-induced transmittance change indicates distinct nonlinearity related to the Zener tunneling in narrow band-gap materials.
Transient Fano Resonance in topological insulators observed by coherent phonon spectroscopy
Authors: Mondal Richarj , Arai Akira , Saito Yuta , Fons Paul , Kolobov Alexander V. , Tominaga Junji , Hase Muneaki
Published: April 2019

We report upon observation of a transient Fano resonance, a quantum interference between coherent phonon and Dirac plasmons, that persisted for up to 1 picosecond in the topological insulator Sb2Te3 investigated using coherent phonon spectroscopy.
Ultrafast optical response of plasmonic structures beyond the perturbative regime: evidence of universal saturation dynamics
Authors: Silva Mychel Gonçalves , Teles-Ferreira Danielle Cristina , Manzoni Cristian , Ganzer Lucia , Siman Livia , Chaves Claudilene Ribeiro , Ladeira Luiz Orlando , Cerullo Giulio , Longhi Stefano , De Silvestri Sandro , Della Valle Giuseppe , de Paula Ana Maria
Published: April 2019

The transient optical response of gold nanorods is investigated beyond the perturbative regime. Ultrafast pump-probe spectroscopy and semiclassical modeling of hot electrons reveal a universal mechanism presiding over the saturation of nonlinear plasmonic effects.
Two-color phase-controlled photoemission from a zero-dimensional nanostructure
Authors: Paschen Timo , Förster Michael , Krüger Michael , Lemell Christoph , Wachter Georg , Libisch Florian , Madlener Thomas , Burgdörfer Joachim , Hommelhoff Peter
Published: April 2019

We demonstrate that multi-photon photoemission including above-threshold multiphoton orders from a nanotip can be coherently controlled with the optical phase between two light fields. By focusing 74 fs drive pulses at 1560 nm and their second harmonic at 780 nm onto the tip and changing the optical phase between the two colors, we observe an emission current modulation of up to 97.5 %. Additionally, electron energy spectra reveal a homogeneous modulation of all multiphoton orders. Hence, the electron current can be strongly increased (by a factor of 3.7) or almost completely turned off due to interference between two different quantum channels in the material. We argue that the extremely high degree of coherence evidenced by this near-unity current modulation depth is due to the confinement of the local field enhancement at the nanotip. The nano-rod effect allows to apply large DC fields, adding a further degree of freedom to investigate the modulation contrast of the photoemitted electron yield. We show that for an increasing DC electric field a non-cooperative distribution of electron emission leads to a decrease in modulation contrast.
Lightwave control of the valley pseudospin in a monolayer of tungsten diselenide
Authors: Schmid Christoph P. , Langer Fabian , Schlauderer Stefan , Gmitra Martin , Fabian Jaroslav , Nagler Philipp , Schuller Christian , Korn Tobias , Hawkins Peter G. , Steiner Johannes T. , Huttner Ulrich , Koch Stephan W. , Kira Mackillo , Huber Rupert
Published: April 2019

As conventional electronic is approaching its ultimate limits, tremendous efforts have been taken to explore novel concepts of ultrafast quantum control. Lightwave electronics - the foundation of attosecond science - has opened a spectacular perspective by utilizing the oscillating carrier wave of an intense light pulse to control the translational motion of the electron’s charge faster than a single cycle of light [1-7]. Despite their promising potential as future information carriers [8,10], the internal quantum attributes such as spins and valley pseudospins have not been switchable at optical clock rates. Here we demonstrate a novel subcycle control scheme of the electron’s pseudospin in a monolayer of tungsten diselenide using strong mid-infrared lightwaves [9]. Our work opens the door towards systematic valleytronic protocols at optical clock rates.
Real-time observation of the intravalley spin-flip process in single-layer WS2
Authors: Wang Zilong , Molina-Sanchez Alejandro , Altmann Patrick , Sangalli Davide , De Fazio Domenico , Soavi Giancarlo , Sassi Ugo , Bottegoni Federico , Ciccacci Franco , Finazzi Marco , Wirtz Ludger , Ferrari Andrea , Marini Andrea , Cerullo Giulio , Dal Conte Stefano
Published: April 2019

We use helicity-resolved transient absorption spectroscopy to track intravalley scattering dynamics in monolayer WS2. We find that spin-polarized carriers scatter from upper to lower conduction band by reversing their spin orientation on a sub-ps timescale.
Real-time probing of charge-transfer induced interfacial fields in a dye-semiconductor system using time-resolved XPS
Authors: Mahl Johannes , Neppl Stefan , Roth Friedrich , Shavorskiy Andrey , Huse Nils , Bluhm Hendrik , Eberhardt Wolfgang , Gessner Oliver
Published: April 2019

Photo-induced charge carrier dynamics and transient interfacial fields at the interface between N3 polypyridine complexes and films of nanocrystalline ZnO are probed by picosecond time-resolved X-ray photoelectron spectroscopy.
Femtosecond solvation dynamics of indium dimers inside superfluid helium nanodroplets
Authors: Meyer Miriam , Thaler Bernhard , Heim Pascal , Koch Markus
Published: April 2019

Indium dimers (In2) solvated inside helium nanodroplets are studied with femtosecond photoelectron and photoion spectroscopy. The solvation dynamics triggered by photoexcitation of the In2 include expansion of the solvation shell and dopant ejection from the droplet, which both proceed more slowly than for In atoms. Oscillation of the solvation shell, in contrast, is similar to the case of In atoms. These processes are observed in combination with intrinsic dynamics of the molecule and set the time-frame for the dopant interaction with the quantum fluid environment.
Frustrated double ionization of argon atoms in strong laser fields
Authors: Larimian Seyedreza , Erattupuzha Sonia , Baltuska Andrius , Kitzler Markus , Xie Xinhua
Published: April 2019

We report coincidence measurements of frustrated double ionization of argon atoms with a reaction microscope. Experimental results show electron trap- ping process during double ionization has a clear transition from the nonsequential to the sequential regime.
Femtosecond coherent anti-Stokes Raman scattering (fs-CARS) for temperature and concentration measurements on combustion species using a dual output OPCPA
Authors: Ran Yang , Kerstan Marita , Tunnermann Andreas , Nolte Stefan , Ackermann Roland
Published: April 2019

Using two beam femtosecond coherent anti-Stokes Raman scattering (fs-CARS), temperature and concentration measurements are performed on relevant combustion species such as H2, N2, CO, and CO2.
Two-dimensional electronic spectroscopy reveals ultrafast dynamics at a conical intersection in an organic photovoltaic material
Authors: Sommer Ephraim , De Sio Antonietta , Mena-Osteritz Elena , Bäuerle Peter , Lienau Christoph
Published: April 2019

Two-dimensional electronic spectroscopy with sub-10-fs time resolution reveals signatures of vibronic coupling and wavepacket motion through a conical intersection in the initial charge separation dynamics of an acceptor-donor-acceptor oligomer thin film for organic solar cells.
Simulating exciton migration and annihilation dynamics in higher order spectroscopies of a molecular trimer
Authors: Heshmatpour Constantin , Šanda František , Lincoln Craig N. , Perlík Vaclav , Malevich Pavel , Hauer Jurgen
Published: April 2019

We present simulations of 3rd and 5th order multidimensional time-dependent signals of a molecular trimer. The developed model allows for the simulation of both signal types within one theoretical framework. We therefore extended standard Redfield theory of exciton migration by a new term to include the process of exciton-exciton annihilation.
Strong-field physics in the molecular frame
Authors: Trabattoni Andrea , Trippel Sebastian , De Giovannini Umberto , Olivieri Jean-Frangois , Wiese Joss , Mullins Terry , Onvlee Jolijn , Son Sang-Kil , Frusteri Biagio , Rubio Angel , Küpper Jochen
Published: April 2019

Laser-aligned carbonyl-sulfide molecules were strong-field ionized using mid-infrared light. Investigating the strong-field effects in the molecular frame allowed to add novel facets to the understanding of the intrinsic nature of strong-field physics.
Imaging the ring opening reaction of 1,3-cyclohexadiene with MeV ultrafast electron diffraction
Authors: Wolf Thomas J. A. , Yang Jie , Sanchez David M. , Nunes J. Pedro. F. , Parrish Robert M. , Shen Xiaozhe , Centurion Martin , Coffee Ryan , Gyan James P. , Gühr Markus , Kareem Hegazy , Kirrander Adam , Li Renkai , Ruddock Jennifer , Veccione Theodore , Weathersby Stephen P. , Weber Peter M. , Wilkin Kyle , Yong Hai-Wang , Zheng Qiang , Martinez Todd J. , Wang Xijie , Minitti Michael P.
Published: April 2019

We resolve the structural dynamics of the ultrafast photoinduced ring opening reaction of 1,3-cyclohexadiene in space and time employing megaelectronvolt gas phase ultrafast electron diffraction. We, furthermore, observe coherent large amplitude motions of the photoproduct.
Ultrafast spin crossover in a single crystal
Authors: Field Ryan L. , Liu Lai Chung , Jiang Yifeng , Gawelda Wojciech , Lu Cheng , Miller R. J. Dwayne
Published: April 2019

Femtosecond spectroscopy and electron diffraction are used to characterize spin crossover in single crystal iron(II)-tris(bipyridine)-bis(hexafluorophosphate). The high-spin lifetime is reduced compared to in solution. Preliminary electron diffraction experiments show evidence of ultrafast Fe-N bond elongation associated with spin crossover and the subsequent molecular reorganization resulting from vibrational cooling.
Structural phase transitions and phase ordering at surfaces probed by ultrafast LEED
Authors: Horstmann Jan Gerrit , Storeck Gero , Wit Bareld , Diekmann Theo , Epp Dennis , Rossnagel Kai , Schäfer Sascha , Vogelgesang Simon , Ropers Claus
Published: April 2019

We demonstrate the capability of ultrafast low-energy electron diffraction to resolve phase-ordering kinetics and structural phase transitions on their intrinsic time scales with ultimate surface sensitivity.
Sub-cycle Manipulation of Electrons in a Tunnel Junction with Phase-controlled Single-cycle THz Near-fields
Authors: Yoshioka Katsumasa , Katayama Ikufumi , Arashida Yusuke , Ban Atsuhiko , Kawada Yoichi , Takahashi Hironori , Takeda Jun
Published: April 2019

By utilizing terahertz scanning tunneling microscopy (THz-STM) with a carrier envelope phase shifter for broadband THz pulses, we could successfully control the near-field-mediated electron dynamics in a tunnel junction with sub-cycle precision. Measurements of the phase-resolved sub-cycle electron tunneling dynamics revealed an unexpected large carrier-envelope phase shift between far-field and near-field single-cycle THz waveforms.
From strong-field physics in and at nanoscale matter to photonics-based laser accelerators
Authors: Kozák Martin , Higuchi Takuya , McNeur Joshua , Shiloh Roy , Heide Christian , Paschen Timo , Yousefi Peyman , Sturm Constanze , Li Ang , Illmer Johannes , Meier Stefan , Schönenberger Norbert , Dienstbier Philip , Tafel Alexander , Weber Philipp , Zimmermann Robert , Seidling Michael , Mittelbach Anna , Heimerl Jonas , Eckstein Timo , Hundhausen Martin , Ristein Jürgen , Hommelhoff Peter
Published: April 2019

New ways of controlling quasi-free and free electrons by means of phase-controlled ultrashort laser pulses are demonstrated: from strong-field physics in the conducting 2-d material graphene and at the surface of nanostructures, to laser acceleration of free electrons with a nanophotonic structure, and the demonstration of the longitudinal Kapitza-Dirac effect.
Generation and attosecond shaping of high coherence free-electron beams for ultrafast TEM
Authors: Feist Armin , Priebe Katharina E. , Rathje Christopher , Bach Nora , Rubiano da Silva Nara , Danz Thomas , Moller Marcel , Domrose Till , Rittmann Thomas , Yalunin Sergey. V. , Hohage Thorsten , Sivis Murat , Schafer Sascha , Ropers Claus
Published: April 2019

We demonstrate the generation and optical control of ultrashort high-coherence electron pulses. The free-electron quantum state is phase-modulated in the longitudinal and transverse dimensions, and the formation of attosecond electron pulse trains is quantitatively probed.
Ultrafast stimulated Raman study of the complete reactive potential energy surface of a photomolecular rotor
Authors: Christopher R. Hall , Wesley R. Browne , Ben L. Feringa , Stephen R. Meech
Published: April 2019

Femtosecond Stimulated Raman Spectroscopy (FSRS) reports on structure and dynamics of excited states. Here we record FSRS for a photomolecular motor in its stable and metastable states, and thus map the entire excited state PES.