bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a fiber-bundle-based 2D Raman imaging system for multi-species
Authors: Yu Tao , Sharma Priybrat , Yang Chaobo , Magnotti Gaetano
Published: September 2022

We introduce a novel fiber-bundle-based 2D Raman imaging system, which enables multi-species Raman scattering measurement by using one camera. Through a series of tests, the key specifications of the system are quantified.
Numerical study on the distortions in the closed-aperture z-scan data due to the spherical aberration of the focusing lens
Authors: Cha Hyesun , Jeong Yoonchan
Published: September 2022

In this research, the aberration effect of a focusing lens in the analysis of z-scan data is qualitatively examined. As the numerical aperture increases, the intensity profile before and after the focal point is distributed asymmetrically, distorting the z-scan data.
Measuring the Optical Constants for Adaptable Spectral Libraries
Authors: Peterson Kelly A. , Johnson Timothy J. , Bernacki Bruce E. , Lonergan Charmayne E. , Myers Tanya L.
Published: September 2022

To support stand-off detection, spectral libraries are being developed that include the optical constants, n(ν) and k(ν). Variable angle spectroscopic ellipsometry and single-angle reflectance are used to derive these data, enabling the reference spectra to be modeled for different parameters.
Mid-IR frequency modulation spectroscopy for sensing C2H2 in a dusty plasma
Authors: Pal Mithun , Stuhr Michael , Faßheber Nancy , Petersen Andreas , Greiner Franko , Friedrichs Gernot
Published: September 2022

We have developed a 3 μm mid-IR continuous wave OPO-based two-tone frequency modulation laser absorption technique. The optical spectrometer was characterized and deployed for investigating C2H2 concentration dynamics in a particle forming dusty plasma environment.
Interband cascade laser for trace gas detection with high acquisition rates
Authors: Hoppe Morten , Aßmann Christian , Tatenguem Herve , Schmidtmann Sebastian , Honsberg Martin , Sacher Joachim R. , Gu-Stoppel Shanshan
Published: September 2022

IC-ECLs with straight and curved waveguide concepts are analyzed and presented. The results of the characterization and the use for the detection of trace gases with acquisition rates above 1 kHz are shown.
Burst-Mode Noncollinear Optical Parametric Oscillator
Authors: Gomez Mateo , Slipchenko Mikhail N. , Son Steven F. , Meyer Terrence R.
Published: September 2022

Laser illumination is preferred for visualization of hypersonic flows, but coherent speckle typically limits the spatial resolution. This work develops a burst-mode non-collinear optical parametric oscillator to realize a broadband signal for speckle-free imaging.
High-Speed Imaging Diagnostics of Hypervelocity Projectile-Water Droplet Interactions
Authors: Lukasik Gavin D. , Rogers Jacob A. , Lacy Thomas E. , Kulatilaka Waruna D.
Published: September 2022

MHz-rate schlieren imaging was employed to investigate impact characteristics and shock-droplet interactions between spherical, cylindrical, and ogive shaped hypersonic projectiles traveling at 2–3 km/s speeds.
Simultaneous multiparameter evaluation from laser-induced grating experiments
Authors: Hölzer Jonas I. , Kozlov Dimitrii N. , Seeger Thomas
Published: September 2022

A four-wave mixing signal contribution has been found in 1064 nm pumped laser-induced grating (LIG) experiments in CO2 that allows the otherwise challenging simultaneous determination of multiple thermodynamic parameter.
Creating a Digital Twin of a Photoacoustic Gas Sensor for Methane Detection in Complex Gas Matrices
Authors: Müller Max , Rück Thomas , Jobst Simon , Pangerl Jonas , Bierl Rudolf , Matysik Frank-Michael
Published: September 2022

We present the calculation results from a digital twin (DT) of our photoacoustic (PA) sensor for methane detection, regarding gas composition, temperature and pressure variations.
Minifying photometric stereo via knowledge distillation-based feature translation
Authors: Han Seungoh , Park Jinsun , Cho Donghyeon
Published: September 2022

Photometric stereo (PS) estimates the surface normals of an object by utilizing multiple images captured under different light conditions. To obtain accurate surface normals, a large number of input images is often required. Therefore, a huge effort is needed to capture images and calibrate light directions together with a heavy computational cost. Therefore, in this paper, we propose a robust photometric stereo method even when the number of input images is very small. To this end, we design a feature translation module (FTM) that enriches features having scarce information. In particular, we insert FTMs between the layers of the baseline backbone PS network. Then, activations of each FTM are supervised by distillation loss. For computing distillation loss, we utilize a teacher PS network trained by taking lots of images as inputs. As a result, our PS network requires very few input images but produces a similar quality of output surface normals with the teacher PS network. The proposed method is applicable to both calibrated and uncalibrated PS. We show the effectiveness of the proposed method not only when the number of input images is small but also in various input conditions.
Analytical formulation of quantum interference inside coupled waveguides with unequal losses
Authors: Zhou Junhe
Published: September 2022

In this paper, a theoretical framework is proposed to formulate the quantum interference inside the coupled waveguides with unequal losses. The quantum coupled mode equation is added with the Langevin noise terms to account for the impact of unequal losses, which can be solved analytically. A close form formula is derived for the correlation matrix of the Langevin noise terms, which provides full information for the density matrix of the propagation state. The theory is self-consistent and tested with a three-waveguide system, which is considered as anti-parity-time (PT) symmetric and simulated in the previous publications. An 89-waveguide system is analyzed afterwards to further demonstrate the applicability of the theory.
Characterization of noise regimes in mid-IR free-space optical communication based on quantum cascade lasers
Authors: Seminara Marco , Gabbrielli Tecla , Corrias Nicola , Borri Simone , Consolino Luigi , Meucci Marco , De Natale Paolo , Cappelli Francesco , Catani Jacopo
Published: September 2022

The recent development of Quantum Cascade Lasers (QCLs) represents one of the biggest opportunities for the deployment of a new class of Free Space Optical (FSO) communication systems working in the mid-infrared (mid-IR) wavelength range. As compared to more common FSO systems exploiting the telecom range, the larger wavelength employed in mid-IR systems delivers exceptional benefits in case of adverse atmospheric conditions, as the reduced scattering rate strongly suppresses detrimental effects on the FSO link length given by the presence of rain, dust, fog, and haze. In this work, we use a novel FSO testbed operating at 4.7 µm, to provide a detailed experimental analysis of noise regimes that could occur in realistic FSO mid-IR systems based on QCLs. Our analysis reveals the existence of two distinct noise regions, corresponding to different realistic channel attenuation conditions, which are precisely controlled in our setup. To relate our results with real outdoor configurations, we combine experimental data with predictions of an atmospheric channel loss model, finding that error-free communication could be attained for effective distances up to 8 km in low visibility conditions of 1 km. Our analysis of noise regimes may have a key relevance for the development of novel, long-range FSO communication systems based on mid-IR QCL sources.
HORN-9: Special-purpose computer for electroholography with the Hilbert transform
Authors: Yamamoto Yota , Shimobaba Tomoyoshi , Ito Tomoyoshi
Published: September 2022

Holography is a technology that uses light interference and diffraction to record and reproduce three-dimensional (3D) information. Using computers, holographic 3D scenes (electroholography) have been widely studied. Nevertheless, its practical application requires enormous computing power, and current computers have limitations in real-time processing. In this study, we show that holographic reconstruction (HORN)-9, a special-purpose computer for electroholography with the Hilbert transform, can compute a 1, 920 × 1, 080-pixel computer-generated hologram from a point cloud of 65,000 points in 0.030 s (33 fps) on a single card. This performance is 8, 7, and 170 times more efficient than a previously developed HORN-8, a graphics processing unit, and a central processing unit (CPU), respectively. We also demonstrated the real-time processing and display of 400,000 points on multiple HORN-9s, achieving an acceleration of 600 times with four HORN-9 units compared with a single CPU.
60 Gb/s coherent optical secure communication over 100 km with hybrid chaotic encryption using one dual-polarization IQ modulator
Authors: Wu Yuqing , Luo Hanwen , Deng Lei , Yang Qi , Dai Xiaoxiao , liu Deming , Cheng Mengfan
Published: September 2022

We propose and experimentally study a coherent optical secure transmission system based on one dual-polarization in-phase and quadrature modulator (IQM). One beam of the polarized light is used to generate broadband chaos by configuring a nonlinear opto-electronic oscillator while the other beam carries the encrypted signal. The encrypted signal is obtained through sequential encryption of the analog and digital chaos. The mutual mask of the hybrid chaotic signals can effectively enhance the security performance. Moreover, by varying the encryption depth of analog and digital vectors, the transmission performance can be flexibly adjusted. A commercial dual-polarization IQM could simultaneously generate a chaotic signal and a load message, which provides a high-integration solution. A fast independent component analysis (ICA) algorithm is adopted to compensate for the rotation of state of polarization (RSOP). 60 Gb/s encrypted quadrature phase shift keying (QPSK) signal transmission over 100 km single-mode fiber is realized, and the decrypted bit error rate (BER) performance is below the 7% forward error correction (FEC) threshold (BER = 3.8 × 10−3).
Impulse Response of OAM Beams Propagating Through Turbid Underwater Environment
Authors: Dai Kunjian , Robertson Evan , Wiley Jaxon , Lemon Martyn , Miller J. Keith , Watkins Richard J. , Johnson Eric G.
Published: September 2022

In this paper we demonstrate orbital angular momentum beams propagating through a highly turbid underwater environment. The measured impulse response indicates the potential of using OAM to increase the channel capacity in high turbidity.
Challenges when Partially Training a Machine Learning-Based Optical Communication System in Variable Experimental Conditions
Authors: Jarrett William A. , Avramov-Zamurovic Svetlana , Esposito Joel M. , Nelson Charles
Published: September 2022

We present challenges when training a machine learning-based underwater wireless optical communication system in selected experimental scenarios. The system is tested under different conditions, that include minor beam misalignment and varying optical turbulence.
Comparison of Turbulence Estimates over Water Derived from a Time-Lapse Imaging Technique and from Numerical Weather Prediction with Observation Data
Authors: Wilson Benjamin , Schmidt Jaclyn , Bose-Pillai Santasri , Fiorino Steven
Published: September 2022

The refractive index structure constant, C 2n estimated by a DELTA system over water is compared to modeled values derived from numerical weather and observation data. Better results can be obtained if over the water air temperature is measured.
Automated Classification of Non-Kolmogorov Turbulence Using a Higher-Order Surrogate Function
Authors: Lieb Kevin , Beason Melissa , Wilson Benjamin
Published: September 2022

A method of automated turbulence characterization has been developed for sonic anemometer data. We found that the structure function slope followed an exponential curve and used that observation to incorporate a surrogate function to simplify finding slopes and ranges of turbulence.
Optimize performance of a diffractive neural network by controlling the Fresnel number
Authors: Zheng Minjia , Shi Lei , Zi Jian
Published: September 2022

To achieve better performance of a diffractive deep neural network, increasing its spatial complexity (neurons and layers) is commonly used. Subject to physical laws of optical diffraction, a deeper diffractive neural network (DNN) would be more difficult to implement, and the development of DNN is limited. In this work, we found controlling the Fresnel number can increase DNN’s capability of expression and its spatial complexity is even less. DNN with only one phase modulation layer was proposed and experimentally realized at 515 nm. With the optimal Fresnel number, the single-layer DNN reached a maximum accuracy of 97.08% in the handwritten digits recognition task.
Real-time 3D Shape Sensing with a Random Fiber Bragg Grating Triplet
Authors: Francoeur Jacynthe , Roberge Anthony , Lorre Pierre , Monet Frédéric , Wright Cory , Kadoury Samuel , Kashyap Raman
Published: September 2022

Using an optical frequency domain reflectometry (OFDR) technique, real-time 3D shape sensing of simple and complex bends with an extruded optical fiber triplet with enhanced backscatter power is demonstrated.
Interrogation of 2000 Draw Tower Gratings for Quasi Distributed Sensing with Coherent-Correlation-OTDR
Authors: Azendorf Florian , Voigtländer Christian , Lindner Eric , Schmauss Bernhard , Eiselt Michael
Published: September 2022

Utilizing a Coherent-Correlation-OTDR, 2000 draw tower gratings in 100 meter fiber with a spatial resolution of 50 mm were successfully interrogated. Spooling of the fiber results in variations of the FBG reflection spectra.
A Rydberg Gas Terahertz Sensor
Authors: Torralbo-Campo Lara , Dorsch Eric , Battran Felix , Lue Xiang , Grahn Holger T. , Koelle Dieter , Kleiner Reinhold , Fortágh Jozsef
Published: September 2022

We report the ongoing development of a Rydberg atom-based detector for sensing terahertz radiation. It will be used to characterize the emission properties of a superconducting terahertz emitter and a terahertz quantum-cascade laser.
Spider Dragline Silk-Based Flexible Temperature Sensor
Authors: Zhang Min , Liu Zhihai , Zhang Yu , Zhang Yaxun , Yang Xinghua , Zhang Jianzhong , Yang Jun , Yuan Libo
Published: September 2022

We fabricate a spider silk-based multimode interferometer through evanescent coupling method. The silk is used to achieve light guiding and temperature sensing simultaneously. The sensing structure is encapsulated in PDMS, and made into a flexible and wearable sensor which can be used for real-time monitoring of human body temperature.
GeSbSe Devices for Mid-Infrared Optical Sensing
Authors: Grayson Michael , Krueper Greg , Xu Bo , Hjelme Dag , Gopinath Juliet T. , Park Wounjhang
Published: September 2022

We fabricated GeSbSe waveguides and resonators using e-beam lithography and achieved a propagation loss of 4.4 dB/cm in the mid-infrared region. Using these devices we demonstrated optical sensing of aromatic aldehydes with a limit of detection of 0.25 μmol/mL.
Rapid Electrochemical Preparation of Highly Ordered Surface Enhanced Raman Spectroscopy (SERS) Substrate Based on TiO2-Ag Nanotubes
Authors: Dong Meiling , Wu Shaodong , Liu Yuxin , Pan Shiyan , Yu Ting , Yang Lihong , Lu Lihua , Luo Hongwei , Zhang Wenxin , Chen Jin , Zhu Simian , Wang Yun , Zeng Zhu
Published: September 2022

A highly ordered surface enhanced Raman spectroscopy substrate based on TiO2-Ag nanotubes was prepared using simple and rapid electrochemical method. Its enhancement factor was measured up to 1.5 × 109 using rhodamine 6G probe.
The Effect of In-Fill Pattern of 3D Printed Diffractive Elements on Propagation of Terahertz Radiation
Authors: Aalam Uzair , Bandyopadhyay Aparajita , Sengupta Amartya
Published: September 2022

Zone plates are 3D printed with varying in-fill factors and corresponding broadband THz propagation is recorded. An angular dependent frequency specific feature is noted additional to the FZP response dependent on the in-fill pattern orientation.
Exploring the methylene blue metachromasy to detect LPS endotoxin on the U-bent fiberoptic sensor probe
Authors: Manoharan Hariharan , Shamlee J Kuzhandai , Sai V V R
Published: September 2022

A methylene blue (MB) dye-based lipopolysaccharide (LPS) endotoxin quantification was performed, where the LPS was entrapped on a hydrophobic C-18 layer immobilized U-bent fiberoptic sensor (U-FOS) probe.
Biofunctionalisation of GaAs for sepsis diagnostics, using UV light as the faciliator
Authors: Gomes Bárbara Santos , Masia Francesco
Published: September 2022

The use of GaAs for optical biosensing is prevented by the lack of methodologies reporting its biofunctionalisation. Herein we use XPS to demonstrate spatially selective immobilisation of multiple bioreceptors on GaAs following a photochemical approach.
Conventional vs. pedestal high-contrast grating for biosensing
Authors: Beliaev L. Yu. , Stounbjerg P. G. , Finco G. , Bunea A.-I. , Malureanu R. , Lindvold L. R. , Takayama O. , Andersen P. E. , Lavrinenko A. V.
Published: September 2022

We present a comparative study of novel pedestal and conventional high-contrast grating (HCG) structures for biosensing applications. The pedestal grating demonstrates superior performance both in bulk refractive index (BRIS) and surface sensing.
Next-generation particle sizing: interferometric nanoparticle tracking analysis (iNTA)
Authors: Blessing Martin , Kashkanova Anna D. , Gemeinhardt André , Sandoghdar Vahid
Published: September 2022

Resolving polydispersions in the nanometer regime remains a challenge for state-of-the-art particle sizers. By combining nanoparticle tracking analysis with interferometric scattering microscopy, we precisely estimated the size and refractive index of (in)organic particles in polydispersions.
Single-molecule DNA sensing via plasmon enhanced fluorescence
Authors: Lamberti Vincenzo , Dolci Mathias , Zijlstra Peter
Published: September 2022

We demonstrate a single-molecule DNA sensor that employs plasmon-enhanced fluorescence combined with a sandwich assay. We quantify the dynamic range and detection limit of this new sensor, and discuss future applications.
Staphylococcus Aureus detection based on Etched Few-Mode Interferometer
Authors: Hernández-Ambato V. , Barrera D. , Esteve Y. , Tormo-Mas M. , Aznar E. , Martínez-Mañez R. , Sales. S.
Published: September 2022

A novel sensor based on etched few-mode fiber for Staphylococcus Aureus detection is proposed. We reduced the cladding diameter to improve the interaction with the surrounding medium and functionalized selecting the binding aptamer for detection.
Ultrasensitive Detection of Polycyclic Aromatic Hydrocarbons in Water Using 3D SERS Substrates produced in cold plasma
Authors: Capaccio Angela , Sasso Antonio , Rusciano Giulia
Published: September 2022

We present a simple and effective nanofabrication procedure to produce large-scale 3D nanoporous Ag-based SERS substrates which exhibit excellent spatial reproducibility and EF of about 108. Our substrates can detect polycyclic aromatic hydrocarbons dispersed in water without any functionalization of the surface, reaching a LOD of ~ 20 nM.
Decoupled Structural Responses upon Light and Thermal Functional Activation in CsPbBr3 Perovskites
Authors: Cannelli Oliviero , Wiktor Julia , Colonna Nicola , Leroy Ludmila , Puppin Michele , Bacellar Camila , Sadykov Ilia , Krieg Franziska , Smolentsev Grigory , Kovalenko Maksym V. , Pasquarello Alfredo , Chergui Majed , Mancini Giulia F.
Published: September 2022

We combine time-resolved and temperature-dependent X-ray absorption spectroscopy with state-of-the-art first principles simulations to quantify light- and thermally-induced structural distortions in CsPbBr3 perovskite nanocrystals with atomic-level precision.
Short-Range Slowdown of Water Solvation Dynamics around SO42- - Mg2+ Ion Pairs
Authors: Kundu Achintya , Mamatkulov Shavkat I. , Brünig Florian N. , Bonthuis Douwe Jan , Netz Roland R. , Elsaesser Thomas , Fingerhut Benjamin P.
Published: September 2022

2D-IR spectroscopy in the fingerprint region of SO42- ions in water reveals a counterion specific slowdown of solvation dynamics. Hydration structures of solvent shared SO42- - Mg2+ ion pairs are identified as the molecular origin.
Momentum-Resolved Intervalley and Intravalley Exciton Coupling in Monolayer WS2
Authors: Kunin Alice , Chernov Sergey , Bakalis Jin , Li Ziling , Cheng Shuyu , Withers Zachary H. , White Michael G. , Schönhense Gerd , Du Xu , Kawakami Roland K. , Allison Thomas K.
Published: September 2022

Using time-resolved angle-resolved photoemission spectroscopy (tr-ARPES), we image the dynamics of intervalley and intravalley excitons in monolayer WS2. We observe strong coupling between photoexcited B and A excitons and directly visualize the ultrafast valley depolarization.
Imaging dynamics of exciton interactions and coupling in transition metal dichalcogenides
Authors: Purz Torben L. , Martin Eric W. , Holtzmann William G. , Rivera Pasqual , Alfrey Adam , Bates Kelsey M. , Deng Hui , Xu Xiaodong , Cundiff Steven T.
Published: September 2022

We demonstrate coherent coupling between excitons in a MoSe2/WSe2 heterostructure, as well as rapid interlayer electron and hole transfer. We visualize the spatial homogeneity of the coupling in the presence of significant sample inhomogeneities.
Quantitative sampling of atomic-scale half-cycle terahertz waveforms
Authors: Kastner L.Z. , Peller D. , Roelcke C. , Buchner T. , Neef A. , Hayes J. , Bonafé F. , Sidler D. , Ruggenthaler M. , Rubio A. , Repp J. , Huber R.
Published: September 2022

Measuring ultrafast, near-field waveforms on atomic length scales has remained an open challenge. Using a molecular switch as a local field sensor, we sample the temporal shape and strength of atomically confined light field transients.
Rabi Oscillations in Disguise: Strong Exciton-Surface Plasmon Polariton Coupling Probed by Two-Dimensional Electronic Spectroscopy
Authors: Timmer Daniel , Zhong Jin-Hui , Gittinger Moritz , Quenzel Thomas , Stephan Sven , Zablocki Jennifer , Lützen Arne , Silies Martin , De Sio Antonietta , Lienau Christoph
Published: September 2022

We explore dynamics of strong exciton-plasmon couplings using two-dimensional electronic spectra displaying pronounced Rabi oscillations of their cross-peaks. Radiative couplings govern the polariton nonlinearity and provide first access to the two-quantum-excitations of the coupled system.
Phase-matched absorption-limited HHG using pre-ionization
Authors: Finke O. , Vábek J. , Nevrkla M. , Bobrova N. , Hort O. , Jurkovič M. , Albrecht M. , Jančárek A. , Catoire F. , Skupin S. , Nejdl J.
Published: September 2022

We have discovered that ionization-induced defocusing is the main cause of inefficient high-order harmonic generation in long absorption-limited media. A novel method utilizing pre-ionization to overcome this bottleneck was validated both experimentally and with numerical simulations.
All-Optical Generation of Terahertz Magnetic Impulses
Authors: Jana Kamalesh , Mi Yonghao , Møller Søren H. , Sederberg Shawn , Corkum P. B.
Published: September 2022

We investigate the generation of ultrafast THz magnetic fields. We apply ‘spatially structured’ femtosecond laser pulses to generate and control transient currents in GaAs, which serve as sources of THz magnetic fields with ultrafast risetimes.
Ultrafast Charge Carrier Dynamics in Lead-Free Double-Perovskite Microcrystals
Authors: Mishra Samita , Sapru Shradha , De Arijit K.
Published: September 2022

Ultrafast electron and hole relaxation dynamics in microcrystals of a layered double-perovskite in two solvents is studied and found to proceed at different rates depending on the nature of charge carriers as well as solvents.
Revisiting Photoacidity using R*NH2 Photoacids
Authors: Rozler Haim , Aminov Daniel , Pines Dina , Pines Ehud
Published: September 2022

The 3 most common classes of photoacids, R*NH2, R*NH3+ and R*OH are compared. Clearly the molecular origins of photoacidity need to be considered not as a general phenomenon but separately for each class of photoacids.
1.5mJ, 30W OPCPA at 2um
Authors: Schmidt Bruno E , Wilson Derrek , Ivanov Maksym , Abdolghader Pedram , Raffray Antoine , Balciunas Tadas , Légaré François , Wörner Hans Jakob
Published: September 2022

To reach high average power operation combined with good conversion efficiency we utilize spectrally selective amplification with multiple nonlinear crystals to yield 12% conversion efficiency with 30W output at 2um wavelength.
Multi-frame single-shot ultrafast interferometry of laser-induced surface acoustic waves
Authors: Saiki Takao , Shimada Keitaro , Ishijima Ayumu , Song Hang , Sakuma Ichiro , Nakagawa Keiichi
Published: September 2022

We developed a multi-frame single-shot ultrafast interferometry for quantitative measurements of dynamic phenomena. We observed laser-induced surface acoustic waves on a glass plate coated by 100 nm-thick chromium with 7 frames and 2.0 ns interval.
Confinement-driven Ultrafast Singlet Fission Dynamics in TIPS-pentacene
Authors: Silori Yogita , Yadav Anita , Chawla Sakshi , De Arijit K.
Published: September 2022

The effect of micellar nanocavities on ultrafast singlet fission dynamics of TIPS-pentacene is explored. It is shown how short- and long-range interactions among chromophores affect the efficiency of singlet fission, thereby the yield of triplets.
Tracking Ultrafast Nonadiabatic Dynamics via Electronic Coherences in Twisted X-ray Diffraction
Authors: Yong Haiwang , Rouxel Jérémy R. , Keefer Daniel , Mukamel Shaul
Published: September 2022

Direct observation of electronic coherences at conical intersections (CIs) is challenging. We present a novel ultrafast twisted x-ray diffraction technique that can exclusively track transient electronic coherences at CIs in gas-phase molecules.
Flatfield Ultrafast Imaging with Single-Shot Non-Synchronous Array Photography
Authors: Sheinman Matthew , Erramilli Shyamsunder , Ziegler Lawrence , Hong Mi K. , Mertz Jerome
Published: September 2022

A diffractive optical element, custom echelon, and microlens array are used to achieve ultrafast imaging of at upwards of 4.2 trillion frames per second. We term this new technique Single-Shot Non-Synchronous Array Photography (SNAP).
Controlled acceleration of GeV electron beams in an all-optical plasma waveguide
Authors: Oubrerie K. , Leblanc A. , Kononenko O. , Lahaye R. , Andriyash I.A. , Gautier J. , Goddet J.-P. , Martelli L. , Tafzi A. , Ta Phuoc K. , Smartsev S. , Thaury C.
Published: September 2022

We report on the production of an all-optical plasma waveguide, which is able not only to successfully guide an ultra-intense laser pulse and accelerate electrons but also to be combined to a controlled injection process.
Multipass cell based spectral broadening of 100 mJ from a Yb-doped thin-disk amplifier at 5 kHz with compressibility to sub-45 fs
Authors: Pfaff Y. , Barbiero G. , Rampp M. , Wang H. , Klingebiel S. , Teisset C. Y. , Jung R. , Woldegeorgis A. H. , Brons J. , Saraceno C. J. , Metzger T.
Published: September 2022

We report the multipass cell based nonlinear broadening of 100 mJ from a Yb-doped thin-disk regenerative amplifier at 5 kHz repetition rate and show its compressibility, close to the Fourier-transform limit, to 42 fs.
Guiding of Laser Pulses at the Theoretical Limit – 97% Throughput Hollow-Core Fibers – with subsequent compression to 1.3 cycles
Authors: Jeong Young-Gyun , Labranche Alexis , Piccoli Riccardo , Rovere Andrea , Zanotto Luca , Tempea Gabriel , Wilson Derrek , Ivanov Maksym , Ramirez Alicia , Morandotti Roberto , Légaré François , Razzari Luca , Schmidt Bruno E.
Published: September 2022

We demonstrate Yb laser (170fs) propagation in large a core hollow-core fiber (HCF) with 97.4% transmission. It serves as a pre-compression stage to achieve 1.3 cycle pulses in a second step with 70% overall efficiency
Towards 2 μm, sub-3-cycle Pulse Amplification in OPCPA Pumped by High Energy Nd:YAG lasers
Authors: Budriūnas Rimantas , Girdauskas Vytenis , Stanislauskas Tomas
Published: September 2022

We present a dual-crystal optical parametric chirped pulse amplification scheme that is capable of maintaining sub-3-cycle pulse bandwidth when amplifying 2 μm pulses with 30 ps-long pulses from an Nd:YAG laser. The concept is readily scalable to produce pulses with TW-level peak powers.
Photon-Induced Near-Field Interaction in Ultrafast Low Energy Electron Microscopy
Authors: Wöste Andreas , Hergert Germann , Silies Martin , Wang Dong , Groß Petra , Lienau Christoph
Published: September 2022

We report the first observation of optical near-field coupling to an ultrafast wavepacket of free, low-energy electrons. Transient optical near-fields, highly spatially confined around a nanometer-sized Yagi-Uda-antenna are probed in a point-projection-microscope with 30-fs resolution.
Ultrafast Excited State Dynamics of Triphenyl Imidazole Thiophene Substituted Phthalocyanines
Authors: Ahmed Md Soif , Biswas Chinmoy , Srivishnu K.S , Giribabu L. , Soma V. R. , Raavi Sai Santosh Kumar
Published: September 2022

Thiophene Substituted Copper Phthalocyanines (ThPcCu), used as hole transport material in perovskite solar cell fabrication, is investigated for its ultrafast excited state dynamics. ThPcCu data shows long-lived GSB kinetics ≈ 4.5ns and long-lived triplets.
Ultrafast relaxation of solvated organic molecules studied by XUV time-resolved photoelectron spectroscopy
Authors: Granados C. , Titov E. , Hummert J. , Ikonnikov E. , Haacke S. , Mitric R. , Kornilov O.
Published: September 2022

Time-resolved photoelectron spectropscopy (TRPES) allows tracking ultrafast molecular relaxtion through conical intersections. Here, the implementaion of TRPES for solvated organic molecules is presented and applied to relaxation of aminoazobenzenes as well as several bio-mimetic photoactuators.
Volume effects in attosecond pulse reconstruction and photoemission time-delay retrieval
Authors: Vismarra F. , Borrego-Varillas R. , Wu Y. , Mocci D. , Nisoli M. , Lucchini M.
Published: September 2022

We investigate numerically the effect of a finite spatio-temporal distribution of the fields in streaking spectroscopy. We characterize their impact on pulse reconstruction and the retrieval of the photoemission time-delay.
Real-time imaging of photoemission dynamics through the 1s3p-1s4p resonances of Helium
Authors: Autuori A. , Platzer D. , Lejman M. , Gallician G. , Maëder L. , Covolo A. , Bosse L. , Dalui M. , Bresteau D. , Hergott J.-F. , Tcherbakoff O. , Marroux H.J.B. , Loriot V. , Lépine F. , Poisson L. , Taïeb R. , Caillat J. , Salières P.
Published: September 2022

We study helium two-photon ionization using attosecond electron interferometry in a velocity-map imaging spectrometer. The complete dynamics of the photoemission process is then reconstructed in space and time.
Rotation of Polarization of Light Propagating Through a Gas of Molecular Super-rotors [1]
Authors: Tutunnikov Ilia , Steinitz Uri , Gershnabel Erez , Hartmann Jean-Michel , Milner Alexander A. , Milner Valery , Averbukh Ilya Sh.
Published: September 2022

We present a theoretical-experimental study of polarization rotation of light traveling through a gas of fast-spinning molecules. The long-term behavior of the polarization angle can be used for probing relaxation dynamics in molecular gases.
Ultrafast Dynamics of RuII-polypyridyl Complexes – Photoinduced Ligand Dissociation Dynamics in Gas Phase and Solution
Authors: Israil R. , Schüssler L. , Schmitt M. , Grupe M. , Hütchen P. , Thiel W. R. , Diller R. , Riehn C.
Published: September 2022

Ultrafast electronic dynamics and UV absorption of [RuII(bipyridine)2(nicotinamide)2]2+ isolated in an ion trap reveal by transient photodissociation short time constants and spectra comparable to transient absorption in solution. Ligand dissociation dynamics are elucidated.
Ultrafast Molecular Imaging Using 4-Fold Covariance: Coincidence Insight with Covariance Speed
Authors: Cheng Chuan , Frasinski Leszek J. , Moğol Gönenç , Allum Felix , Howard Andrew J. , Bucksbaum Philip H. , Brouard Mark , Forbes Ruaridh , Weinacht Thomas
Published: September 2022

We develop mathematical tools to compute higher order covariances in charged particle detection, and demonstrate fourfold covariance measurements for molecular imaging with intense ultrafast laser pulses.
Femtosecond LIPSS on indium-tin-oxide thin films at IR wavelengths
Authors: Bánhegyi Balázs , Péter László , Dombi Péter , Pápa Zsuzsanna
Published: September 2022

We investigated laser-induced periodic surface structures (LIPSS) generated on indium-tin-oxide (ITO) thin films with femtosecond laser pulses in the infrared region. Using pulses between 1.6 and 2.4 μm central wavelength, we observed robust LIPSS morphologies with a periodicity close to λ/10. Supporting finite-difference time-domain calculations suggest that the surface forms are rooted in the field localization in the surface pits leading to a periodically increased absorption of the laser pulse energy that creates the observed periodic structures.
Femtosecond time-of-flight mass spectrometry and photoelectron imaging of Z-dihydrodibenzodiazocine
Authors: Pessier Pascal , Hergert Maria , Renth Falk , Temps Friedrich
Published: September 2022

Femtosecond mass spectrometry and photoelectron imaging of gaseous Z-dihydrodibenzodiazocine reveals ultrafast depopulation of the S1 state within 38 fs, probe-wavelength dependent ionization pathways and adiabatic ionization to the D0 state at IE = 8.6 eV.
Coupled electronic and protonic motion in H2O in intense laser fields by extended multi-configuration time-dependent Hartree-Fock method
Authors: Wang Lidong , Kimura Ryuto , Kato Tsuyoshi , Yamanouch Kaoru
Published: September 2022

We investigated the correlated motion of electrons and protons in H2O induced by an ultrashort intense ultraviolet laser field using the Ex-MCTDHF method and identified electronic and vibrational excitations proceeding simultaneously.
Generation of frequency tunable ultraviolet pulses for steering and imaging of photoreaction dynamics
Authors: Rashtabadi Hamid A. , Prandolini Mark J. , Schmitt Nora , Wieland Marek , Drescher Markus
Published: September 2022

Frequency tunable resonant dispersive waves are generated in a compact cascaded hollow-core fiber setup pumped by a Ti:sapphire laser. The UV pulses with a Fourier limit of 1.3 fs are effective tools for observing and controlling extremely fast electronic dynamics in molecules.
High harmonic generation in a flat water-jet with double MIR pulses
Authors: Yang Tianqi , Kurihara Takayuki , Mizuno Tomoya , Kanai Teruto , Harada Yoshihisa , Itatani Jiro
Published: September 2022

We produce high harmonics in a water jet with double MIR pulses at 3.2 µm. Persistent vibrational oscillation is induced by the first pulse which modulates high harmonic generation by the second pulse.
Terahertz light-induced nonlinear coupling between distinct magnon modes in a canted antiferromagnet
Authors: Zhang Zhuquan , Gao Frank Y. , Liu Zi-Jie , Chien Yu-Che , Nelson Keith A. , Baldini Edoardo
Published: September 2022

Identifying the signature of couplings has been elusive in conventional spectroscopies. Here, we discover the fingerprints of correlation between two distinct magnons in an antiferromagnet, as evidenced by off-diagonal peaks in the two-dimensional terahertz spectroscopy.
Observation of Polariton-Assisted Long-Range Energy Transfer in Semiconducting Carbon Nanotube Microcavity by 2D White-Light Spectroscopy
Authors: Son Minjung , Armstrong Zachary T. , Allen Ryan T. , Dhavamani Abitha , Arnold Michael S. , Zanni Martin T.
Published: September 2022

We resolve a sub-picosecond long-range energy transfer pathway in a carbon nanotube microcavity using 2D white-light spectroscopy. This pathway is primarily mediated by polaritonic states, highlighting the role of light-matter coupling in controlling the photophysics.
Non-integer High-Harmonic Generation from a Topological Insulator Surface
Authors: Meierhofer M. , Schmid C. P. , Weigl L. , Grössing P. , Junk V. , Gorini C. , Schlauderer S. , Ito S. , Hofmann N. , Afanasiev D. , Crewse J. , Kokh K. A. , Tereshchenko O. E. , Güdde J. , Evers F. , Wilhelm J. , Richter K. , Höfer U. , Huber R.
Published: September 2022

We selectively explore bulk-versus-surface high-harmonic generation in a topological insulator by tuning the driving frequency. Ballistic acceleration of Dirac currents manifests in continuously tunable non-integer harmonic orders and unique polarization fingerprints of the topological invariant.
Femtometer-precision vibrational metrology in molecules with TR-XAS
Authors: Rupprecht Patrick , Aufleger Lennart , Heinze Simon , Magunia Alexander , Ding Thomas , Rebholz Marc , Amberg Stefano , Mollov Nikola , Henrich Felix , Haverkort Maurits , Ott Christian , Pfeifer Thomas
Published: September 2022

We measure the perturbatively excited symmetric breathing mode vibration A1
g
in SF6 via time-resolved x-ray absorption spectroscopy. Vibrational amplitudes of 50 fm were resolved. An ab-initio simulation confirms the results and reveals additional electronic coupling.
Spectral Splitting of High Harmonic Generation in Extreme High-power Chirped Pulses
Authors: Levi Raz Halifa , Levanon Ori Ildis Assaf , Pomerantz Ishay
Published: September 2022

We demonstrate the spectral splitting of high-harmonics generated from gas, when an extreme amount of temporal chirp is applied to a 20 TW peak power driving laser pulse.
Two ways to calculate momentum expectation values with different quantum probability and flux densities
Authors: Schaupp Thomas , Renziehausen Klaus , Barth Ingo , Engel Volker
Published: September 2022

Using the Ehrenfest theorem, two possibilites are regarded to calculate momentum expectation values. They lead to different quantum probability and flux densities being illustrated with numerical results from a model for coupled electron-nuclear motion.
Extracting the linear terahertz properties of thin films using complementary transmission and reflection measurements: Applied to GeSn thin films
Authors: Carnio B. N. , Attiaoui A. , Assali S. , Moutanabbir O. , Elezzabi A. Y.
Published: September 2022

Complementary reflection and transmission measurements are used in conjunction with a Fresnel-based modeling approach to determine the refractive index and extinction coefficient of thin film layers, despite no prior knowledge of the substrate’s extinction coefficient.
Ultrafast Demagnetization Dynamics Excited by Near-Infrared to Mid-Infrared Pulses
Authors: Légaré Katherine , Barrette Guillaume , Lassonde Philippe , Légaré François
Published: September 2022

Ultrafast demagnetization is investigated for different excitation wavelengths in the near- and mid-infrared spectral regions. While the initial drop in magnetization remains unchanged, the recovery dynamics are found to be wavelength dependent.
Two-pulse enabled coherent control of structural dynamics
Authors: Zheng Jiaoyang , Khalsa Guru , Benedek Nicole A. , Moses Jeffrey
Published: September 2022

We predict a new pathway for ultrafast coherent control of fully symmetric Raman phonons, allowing manipulation of sign, magnitude, and temporal response, enabled by the nonlinear lattice polarizability and a two-terahertz-pulse excitation sequence.
Detachment of electrons from negative ions beyond the dipole approximation
Authors: Kahvedžić Rešad , Grafe Stefanie
Published: September 2022

Applying our strong-field approximation approach with non-dipole corrections to the process of electron detachment from anions in intense mid-infrared fields, we analyze the differences between photoelectron spectra obtained with dipole approximation and with non-dipole corrections.
3D Velocity Map Imaging of Electrons
Authors: Moğol Gönenç , Cheng Chuan , Weinacht Thomas , Nomerotski Andrei , Trallero–Herrero Carlos
Published: September 2022

We develop a technique to resolve photoelectron momenta in 3 dimensions using a fast event-based camera (TPX3CAM). Our method is versatile and can be readily implemented in most velocity map imaging systems. We demonstrate this capability in the example of above threshold ionization of Xenon.
Temporal Characterization of a Supercontinuum at 500 kHz Repetition Rate Using Frequency Resolved Optical Switching
Authors: Haddad Elissa , Longa Adrien , Lassonde Philippe , Leblanc Adrien , Ibrahim Heide , Légaré François , Jargot Gaëtan
Published: September 2022

We show that frequency resolved optical switching (FROSt) can be used to characterize high repetition rate laser sources. We characterize supercontinuum pulses extending from 1.2 µm to 1.8 µm up to 500 kHz.
femtoPro: Ultrafast Phenomena in Virtual Reality
Authors: Müller Stefan , Brixner Tobias , Knote Andreas , Schnepp Wilhelm , Truman Samuel , Vetter Anne , von Mammen Sebastian
Published: September 2022

We introduce “femtoPro,” an interactive simulator of an ultrafast laser laboratory in virtual reality (VR). Gaussian beam propagation as well as linear and nonlinear optical phenomena are calculated in real time on consumer-grade VR devices.
Carbon 1s Edge Induced Femtosecond Nonradiative Decays in Tropone Dication (C7H7O2+)
Authors: Yamazaki Kaoru , Midorikawa Katsumi
Published: September 2022

We found that tropone dications (C7H7O2+) created by the carbonKLLnormal Auger decay undergo nonradiative decays via 10-102dicationic states in the time scale of 102fs using surface hopping nonadiabatic reaction dynamics simulations.
High-lying Rydberg-state dynamics of Iodomethane
Authors: Waters Max D.J. , Wörner Hans Jakob
Published: September 2022

The high-lying Rydberg states of iodomethane are accessed using a femtosecond HHG source. The dynamics of this state are tracked using velocity-map-imaging of the photoelectrons generated by UV-photoionisation, which reveal sub-50 fs relaxation.
A qualitative investigation of facilitators and barriers to DREAMS uptake among adolescents with grandparent caregivers in rural KwaZulu-Natal, South Africa
Authors: Gumede Dumile , Meyer-Weitz Anna , Zuma Thembelihle , Shahmanesh Maryam , Seeley Janet
Published: September 2022

Adolescents with grandparent caregivers have experienced challenges including the death of one or both parents due to HIV in sub-Saharan Africa. They may be left out of existing HIV prevention interventions targeting parents and children. We investigated the facilitators and barriers to DREAMS (Determined, Resilient, Empowered, AIDS-free, Mentored and Safe) programme uptake among adolescents with grandparent caregivers across different levels of the socio-ecological model in rural South Africa. Data were collected in three phases (October 2017 to September 2018). Adolescents (13–19 years old) and their grandparent caregivers (≥50 years old) (n = 12) contributed to repeat in-depth interviews to share their perceptions and experiences regarding adolescents’ participation in DREAMS. Data were triangulated using key informant interviews with DREAMS intervention facilitators (n = 2) to give insights into their experiences of delivering DREAMS interventions. Written informed consent or child assent was obtained from all individuals before participation. All data were collected in isiZulu and audio-recorded, transcribed verbatim and translated into English. Thematic and dyadic analysis approaches were conducted guided by the socio-ecological model. Participation in DREAMS was most effective when DREAMS messaging reinforced existing norms around sex and sexuality and when the interventions improved care relationships between the adolescents and their older caregivers. DREAMS was less acceptable when it deviated from the norms, raised SRH information that conflicts with abstinence and virginity, and when youth empowerment was perceived as a potential threat to intergenerational power dynamics. While DREAMS was able to engage these complex families, there were failures, about factors uniquely critical to these families, such as in engaging children and carers with disabilities and failure to include adolescent boys in some interventions. There is a need to adapt HIV prevention interventions to tackle care relationships specific to adolescent-grandparent caregiver communication.
Mapping artisanal and small-scale mines at large scale from space with deep learning
Authors: Couttenier Mathieu , Di Rollo Sebastien , Inguere Louise , Mohand Mathis , Schmidt Lukas
Published: September 2022

Artisanal and small-scale mines (asm) are on the rise. They represent a crucial source of wealth for numerous communities but are rarely monitored or regulated. The main reason being the unavailability of reliable information on the precise location of the asm which are mostly operated informally or illegally. We address this issue by developing a strategy to map the asm locations using a convolutional neural network for image segmentation, aiming to detect surface mining with satellite data. Our novel dataset is the first comprehensive measure of asm activity over a vast area: we cover 1.75 million km2 across 13 countries in Sub-Tropical West Africa. The detected asm activities range from 0.1 ha to around 2, 000 ha and present a great diversity, yet we succeed in hitting acceptable compromises of performance, as achieving 70% precision while maintaining simultaneously 42% recall. Ultimately, the remarkable robustness of our procedure makes us confident that our method can be applied to other parts of Africa or the world, thus facilitating research and policy opportunities in this sector.
Self-efficacy and perceived recognition by peers, instructors, and teaching assistants in physics predict bioscience majors’ science identity
Authors: Cwik Sonja , Singh Chandralekha
Published: September 2022

Prior research shows that in a particular science domain, students’ identity depends on their self-efficacy, perceived recognition by others, and their interest in that domain. In this study, we investigated how the end of the semester physics self-efficacy and perceived recognition by others for bioscience majors enrolled in the second semester of a traditionally taught mandatory physics course sequence predict their overall science identity aligned with their disciplinary major. We find that bioscience majors’ physics self-efficacy and perceived recognition not only predict their physics identity but also their overall science identity. These relations between physics self-efficacy and perceived recognition and the overall science identity of bioscience majors suggest interdisciplinary connections that may provide additional pathways for boosting students’ science identity, e.g., by enhancing their self-efficacy and perceived recognition in their other mandatory courses such as physics. We also find that on average, women majoring in bioscience had lower physics self-efficacy, perceived recognition, physics identity, and overall science identity than men even though women were not underrepresented in the physics course. One possible reason is that the societal stereotypes and biases pertaining to who can excel in physics can impact women who are constantly exposed to them throughout their life.