bluuebunny/crossref_metadata_2025 huggingface dataset:
Solar Flare and Radio Burst Effects on GNSS Signals and the Ionosphere During September 2017
Authors: de Paula Eurico R. , Martinon André R. F. , Carrano Charles , Moraes Alison O. , Neri José A. C. F. , Cecatto José R. , Abdu Mangalathayil A. , Neto Acácio C. , Monico João F. G. , da Costa Silva Weverton , Vani Bruno C. , Batista Inez S. , Mendes Odim , de Souza Jonas R. , Silva André L. A.
Published: October 2022

Strong solar flare events can occur even during the decay phase of the solar cycle. During these events concurrent increases in the X‐ray and Enhanced UV (EUV) fluxes and solar radio bursts (SRBs) can be observed. The SRBs cover a large range of frequencies including the L band, giving rise to signal fades in the GNSS carrier‐to‐noise ratio and fluctuations in its amplitude and phase. The increases in the X‐ray, UV, and EUV fluxes cause increase in the ionospheric D, E, and F region electron densities. The aim of this work is to analyze the effects in the GNSS signal, in the ionosphere and in the magnetic field H component of the X9.3 and X1.3 solar flares that occurred on 06 and 07 September 2017, respectively. Data from a network of six GNSS receivers, two magnetometers, and four Digisondes are used in the analysis. Fades of about 5 and 10 dB were observed in the signals of GNSS L1 and L2/L5 frequencies, respectively. Significant positioning errors, were observed for the strongest X9.3 flare. A sudden increase in Total Electron Content with the rates of 2.5–5.0 TECU/min was observed. An increase in the E layer density gave origin to an increase in the Equatorial Electrojet intensity, whose signatures were observed in the H component of two magnetometers. Another observed effect was the ionospheric D region density increase that caused disruption in the Digisonde signal. As a consequence of the described effects, GNSS receivers may fail to produce accurate navigation solution.
Structural and Metamorphic History of the Leech River Shear Zone, Vancouver Island, British Columbia
Authors: Seyler C. E. , Kirkpatrick J. D. , Faber C. , Licht A. , Šilerová D. , Regalla C.
Published: October 2022

The Leech River Shear Zone (LRSZ) on southern Vancouver Island separates the metasedimentary schists of the Leech River Complex (LRC) from the accreted oceanic plateau of the Siletz‐Crescent terrane. The juxtaposition of these rock units suggests a possible origin as a subduction plate boundary but tectonic context of the LRSZ has yet to be fully established. We present field, microstructural, petrological, and geochronological observations that constrain the structural and metamorphic history of LRSZ. The mylonite zone of the LRSZ straddles the lithologic contact between the schists of the LRC and basalts of the Siletz‐Crescent terrane. Foliation orientations, a steeply plunging stretching lineation, and kinematic indicators all suggest reverse‐sinistral motion. Compositions of garnet in the schist and amphibole in the metabasalt record synkinematic growth at temperature and pressure conditions of 550°C–570°C and 450–490 MPa. These metamorphic conditions require elevated geotherms that are consistent with plate models that position the Kula‐Farallon Ridge and Yellowstone Hotspot in the region in the Eocene (∼50 Ma). Detrital zircon U‐Pb age distributions for the Leech River Schist have Paleocene maximum depositional ages and are similar to the Upper Nanaimo Group that unconformably overlies the Wrangellia terrane. Our ages support early Paleocene deposition of the schist in a subduction trench/slope environment followed by underthrusting and underplating. These results establish the exhumed mylonite zone of the LRSZ as a paleo‐plate interface that was active during Eocene subduction.
Attribution and Predictability of Climate‐Driven Variability in Global Ocean Color
Authors: Lim Hyung‐Gyu , Dunne John P. , Stock Charles A. , Kwon Minho
Published: October 2022

For over two decades, satellite ocean color missions have revealed spatio‐temporal variations in marine chlorophyll. Seasonal cycles and interannual changes of the physical environment drive the nutrient and chlorophyll variations. In order to identify contributions of seasonal and interannual components on chlorophyll, the present study investigates total chlorophyll variance (TCV) of a 24 year records (September 1997 to December 2021) across satellite generations. First‐order contributions of the seasonal cycle in the mid‐latitude (25°–35°) oceans in the Northern and Southern Hemispheres explain 59.5% and 69.9% of TCV, respectively. In contrast, the contribution of seasonal cycle only explain 30.9% in the tropical oceans (20°N–20°S). Both seasonal cycle‐ and climate‐driven variability (26.3%) explain 57.2% on TCV in the tropical oceans. A multiple linear regression model was forced by instantaneous and delayed effects of oceanic memory of eight climate indices based on sea surface temperature anomalies to reconstruct chlorophyll anomalies. Delayed climate effects generally boost the anomaly correlation coefficients (ACC) between the observed and reconstructed chlorophyll timeseries (ACC skills: 0.64 to 0.72 in the Indian Ocean, 0.74 to 0.82 in off‐equatorial Northern Pacific, and 0.58 to 0.71 in the off‐equatorial Southern Pacific). Such delayed climate effects provide a source of predicted chlorophyll ACC (ACC_predic) skills one season ahead in some ocean regions (ACC_predic skill: 0.63 in the overall tropical ocean, 0.67 in the tropical Pacific, and 0.60 in the Indian Ocean). The attribution of chlorophyll variability indicates promising avenues for improving marine ecosystem predictions with Earth system models by incorporating delayed climate effects.
Paleogeographic Reconstructions of an Ocean Margin on Mars Based on Deltaic Sedimentology at Aeolis Dorsa
Authors: Cardenas Benjamin T. , Lamb Michael P.
Published: October 2022

The evidence for an ancient ocean in Mars' northern hemispheric basin during the Noachian/Hesperian is contentious. Much of the work is based on the modern topography by assuming that erosion has not significantly reshaped the Martian surface over the last 3.5 billion years, despite evidence to the contrary. Here, we provide new evidence for a northern ocean or large sea based on stratigraphic analysis of sedimentary basin fill exposed at Aeolis Dorsa. We mapped over 6,500 km of fluvial ridges, grouped them into 20 systems, and present evidence that they are the eroded remnants of river deltas or submarine‐channel belts, together defining the stratigraphy of an ancient ocean margin. We used Context Camera stereo‐pair elevation models to measure the stratigraphic positions of each system and used branching directions to determine paleoflow directions. By grouping landforms based on stratigraphic position and paleoflow directions, we reconstructed the paleogeography at Aeolis Dorsa over 5 timesteps; all cases differ from the modern topography. We tracked the initial regression and later transgression of a shoreline during at least 900 m of sea‐level rise, a scale consistent with a northern ocean on a warm and wet early Mars.
Variations of Primary Productivity in the Northwestern Arabian Sea During the Last 23,000 Years and Their Paleoclimatological Implications
Authors: Zhou Xinquan , Duchamp‐Alphonse Stéphanie , Kageyama Masa , Bassinot Franck , Doressoundiram Florian , Kissel Catherine
Published: October 2022

The Arabian Sea (AS) is one of the most productive oceanic regions in the world due to several monsoon‐related processes that can increase nutrients contents in the euphotic zone. Previous studies of the imprint of oceanic primary productivity (PP) in AS sediments yielded diverse results depending on the studied area and the chosen proxies, with unprecise paleoclimatic interpretations. Here, we provide multi‐decennial PP and coastal upwelling dynamic records off northern Oman over the last 23 Kyr, based on the analysis of coccoliths from sediment core MD00‐2354. Our results have been compared with previous paleoenvironmental records as well as new modeling data to get precise paleoclimatic interpretations. We document higher PP and weaker coastal upwelling during the Last Glacial Maximum relative to the Holocene, and significant millennial‐scale variations over the last deglaciation corresponding to the fluctuations of the Atlantic Meridional Overturning Circulation strength. Higher PP and weaker upwelling are found during the cold stadials, while lower PP and stronger upwelling during the warm interstadial. We propose that the increases of PP were driven by increased bioavailable nutrient content in surface waters under both stronger winter monsoon conditions that strengthened the convective mixing, and higher aeolian inputs. Over the Holocene, stronger upwelling and slightly lower PP are found during the Early‐Mid Holocene, when higher summer insolation triggered stronger summer monsoon. At that time, the lower PP was probably the result of restricted advection of eutrophic summer upwelling seawater under negative wind stress curls and less aeolian inputs.
Bioelectrical impedance analysis to estimate one-repetition maximum measurement of muscle strength for leg press in healthy young adults
Authors: Sue Keita , Kobayashi Yukino , Ito Mitsuru , Midorikawa-Kijima Maiko , Karasawa Shunichi , Katai Satoshi , Momose Kimito
Published: October 2022

Resistance training (RT) progress is determined by an individual’s muscle strength, measured by one-repetition maximum (1RM). However, this evaluation is time-consuming and has some safety concerns. Bioelectrical impedance analysis (BIA) is a valid and easy-to-use method to assess skeletal muscle mass (SMM). Although BIA measurements are often correlated with muscle strength, few studies of 1RM for RT and BIA measurements are available. This observational study examined the relationship between 1RM and BIA measurements and developed BIA-based prediction models for 1RM. Thirty-five healthy young Japanese adults were included. SMM and the skeletal muscle mass index (SMI) were measured using the BIA device. In addition, dominant-leg 1RM was measured using a unilateral leg-press (LP) machine. The correlations between BIA measurements and 1RM were calculated, and simple regression analyses were performed to predict 1RM from the BIA variables. The results showed significant correlations between 1RM and dominant-leg SMM (R = 0.845, P = 0.0001) and SMI (R = 0.910, P = 0.0001). The prediction models for 1RM for LP derived from SMM of the dominant leg and SMI were Y = 8.21x + 8.77 (P = 0.0001), R2 = 0.73, and Y = 15.53x − 36.33 (P = 0.0001), R2 = 0.83, respectively. Our results indicated that BIA-based SMI might be used to predict 1RM for LP accurately.
Hydrodynamic analysis of the magnetic field dependent viscous fluid flow and thermosolutal convection between rotating channels
Authors: Khan Aamir , Khan Muhammad Sohail , Pasha Amjad Ali , Marzouki Riadh , Rahman Mustafa Mutiur , Mahmoud Omar , Galal Ahmed M. , Najati S. A.
Published: October 2022

According to research, exposing a person to a magnetic field enhances blood flow and minimizes their risk of suffering a heart attack. Ferrohydrodynamics is the study of fluid motion mechanics that is affected by strong magnetic polarisation forces (FHD). Ferrofluids may transmit heat in a variety of ways by using magnetic fluids. This behaviour is demonstrated by liquid-cooled speakers, which utilise less ferrofluid to prevent heat from reaching the speaker coil. This modification boosts the coil’s ability to expand, which enables the loudspeaker to create high-fidelity sound. It is investigated how the fluid dynamics of spinning, squeezing plates are affected by thermosolutal convection and a magnetic field dependent (MFD) viscosity. Standard differential equations are used to represent the equations of the modified form of Navier Stokes, Maxwell’s, and thermosolutal convection. The magnetic field, modified velocity field equations, and thermosolutal convection equations all yield suitable answers. Additionally computed and thoroughly detailed are the MHD torque and fluid pressure that are imparted to the top plate. To create a technique with quick and certain convergence, the resulting equations for uniform plates are solved using the Homotopy Analysis Method (HAM) with appropriate starting estimates and auxiliary parameters. The validity and reliability of the HAM outcomes are shown by comparing the HAM solutions with the BVP4c numerical solver programme. It has been found that a magnetic Reynolds number lowers the temperature of the fluid as well as the tangential and axial components of the velocity field. Additionally, when the fluid’s MFD viscosity rises, the axial and azimuthal components of the magnetic field behave in opposition to one another. This study has applications in the development of new aircraft take-off gear, magnetorheological airbags for automobiles, heating and cooling systems, bio-prosthetics, and biosensor systems.
Development and validation of machine learning for early mortality in systemic sclerosis
Authors: Foocharoen Chingching , Thinkhamrop Wilaiphorn , Chaichaya Nathaphop , Mahakkanukrauh Ajanee , Suwannaroj Siraphop , Thinkhamrop Bandit
Published: October 2022

Clinical predictors of mortality in systemic sclerosis (SSc) are diversely reported due to different healthcare conditions and populations. A simple predictive model for early mortality among patients with SSc is needed as a precise referral tool for general practitioners. We aimed to develop and validate a simple predictive model for predicting mortality among patients with SSc. Prognostic research with a historical cohort study design was conducted between January 1, 2013, and December 31, 2020, in adult SSc patients attending the Scleroderma Clinic at a university hospital in Thailand. The data were extracted from the Scleroderma Registry Database. Early mortality was defined as dying within 5 years after the onset of SSc. Deep learning algorithms with Adam optimizer and different machine learning algorithms (including Logistic Regression, Decision tree, AdaBoost, Random Forest, Gradient Boosting, XGBoost, and Autoencoder neural network) were used to classify SSc mortality. In addition, the model’s performance was evaluated using the area under the receiver operating characteristic curve (auROC) and its 95% confidence interval (CI) and values in the confusion matrix. The predictive model development included 528 SSc patients, 343 (65.0%) were females and 374 (70.8%) had dcSSc. Ninety-five died within 5 years after disease onset. The final 2 models with the highest predictive performance comprise the modified Rodnan skin score (mRSS) and the WHO-FC ≥ II for Model 1 and mRSS and WHO-FC ≥ III for Model 2. Model 1 provided the highest predictive performance, followed by Model 2. After internal validation, the accuracy and auROC were good. The specificity was high in Models 1 and 2 (84.8%, 89.8%, and 98.8% in model 1 vs. 84.8%, 85.6%, and 98.8% in model 2). This simplified machine learning model for predicting early mortality among patients with SSc could guide early referrals to specialists and help rheumatologists with close monitoring and management planning. External validation across multi-SSc clinics should be considered for further study.
Deep residual neural-network-based robot joint fault diagnosis method
Authors: Pan Jinghui , Qu Lili , Peng Kaixiang
Published: October 2022

A data driven method-based robot joint fault diagnosis method using deep residual neural network (DRNN) is proposed, where Resnet-based fault diagnosis method is introduced. The proposed method mainly deals with kinds of fault types, such as gain error, offset error and malfunction for both sensors and actuators, respectively. First, a deep residual network fault diagnosis model is derived by stacking small convolution cores and increasing the core size. meanwhile, the gaussian white noise is injected into the fault data set to verify the noise immunity for the proposed deep residual network. Furthermore, a simulation is conducted, where different fault diagnosis methods including support vector machine (SVM), artificial neural network (ANN), convolutional neural network (CNN), long-term memory network (LTMN) and deep residual neural network (DRNN) are compared, and the simulation results show the accuracy of fault diagnosis for robot system using DRNN is higher, meanwhile, DRNN needs less model training time. Visualization analysis proved the feasibility and effectiveness of the proposed method for robot joint sensor and actuator fault diagnosis using DRNN method.
An innovative diagnosis in gastrointestinal neuroendocrine neoplasms using Wax-Physisorption-Kinetics-based FTIR Imaging
Authors: Chen Yi-Ting , Huang Pei-Yu , Wang Jaw-Yuan , Lee Yao-Chang , Chai Chee-Yin
Published: October 2022

Neuroendocrine neoplasm (NEN) is a common gastrointestinal (GI) tract tumor divided into the neuroendocrine tumor (NET) and neuroendocrine carcinoma (NEC) according to mitosis and Ki-67 index. However, the objective discordance between interobserver may cause unsuitable diagnosis and misleading treatment. Nowadays, aberrant glycosylation of glycoconjugates inducing further populations of elongated complex oligosaccharide covalent attached to glycoconjugates anchored in the cell membrane by neo-synthesis of cancer-associated alteration of carbohydrate determinants were observed during cancer development. This study aimed to demonstrate the wax physisorption kinetics coupled with Fourier transform infrared (WPK-FTIR) imaging between NET and NEC in the rectum, colon, and stomach by utilizing two wax reagents (beeswax and paraplast) as glycan adsorbents for physical binding glycans of glycoconjugates based on dipole-induced dipole interaction. Results showed greater physisorption with beeswax than that of paraplast, suggesting highly populated elongated glycans of glycoconjugates adhering onto the tumor surfaces of NETs than that of adjacent benign mucosa in the rectum and colon. Besides, the WPK results of gastric NEN tissue sections showed a higher infrared absorbance ratio of beeswax-remnant to paraplast-remnant remains onto the tissue sections referring to a higher population of elongated glycans in gastric NET as compared with that of gastric NEC. Based on our findings, different anatomical locations could share similar phenomena with minor variance. In conclusion, WPK-FTIR imaging may have the potential to be employed as an alternative diagnostic method in GI NENs in the future.
Correction: Mass-shift mode to quantify low level 129I in environmental samples by ICP-MS/MS
Authors: Carrier Coralie , Habibi Azza , Agarande Michelle , Augeray Celine , Bourles Didier , Maro Denis , Benedetti Lucilla
Published: October 2022

Correction for ‘Mass-shift mode to quantify low level 129I in environmental samples by ICP-MS/MS’ by Coralie Carrier et al., J. Anal. At. Spectrom., 2022, 37, 1309–1317, https://doi.org/10.1039/D2JA00128D.
Long-term multi-wavelength variability and extreme spectral properties of the TeV-detected blazar 1ES 0033+595
Authors: Kapanadze B. , Gurchumelia A.
Published: October 2022

Context. The multi-wavelength (MWL) properties of some TeV-detected blazars are still poorly understood. By studying the MWL properties of the BL Lacertae source 1ES 0033+595, we make further progress in our understanding of the instable physical processes responsible for particle acceleration to ultra-relativitic energies and the observed emission properties.

Aims. This paper presents the results of a detailed X-ray timing and spectral analysis of the source 1ES 0033+595, allowing us to draw conclusions about the physical mechanisms responsible for particle acceleration and the generation of X-ray emission. We also examined the long-term MWL behaviour of the source and interband cross-correlations.

Methods. Our study focused on the observations performed with the X-Ray Telescope on board the Neil Gehrels Swift Observatory (Swift-XRT) in the period 2005–2022. The MWL data sets were obtained with several space and ground-based instruments. We analysed the MWL flaring behaviour during the entire period, as well as in particular subperiods selected on the basis of the X-ray flaring activity of the target; constructed histograms characterising the distributions of the different spectral parameters and MWL fluxes; and checked cross-correlations between these parameters and/or MWL fluxes. The obtained results are compared with the predictions of the various theoretical studies and simulations presented by the different authors to date.

Results. The source showed extreme spectral properties with dominance of high spectral curvature, frequent occurrence of very and extremely hard photon indices, and the presence of a synchrotron spectral energy distribution (SED) peak in the hard X-ray range (sometimes at energies beyond 10 keV). These properties reveal the importance of first-order Fermi acceleration with very low initial particle energy distribution, along with the co-existence of stochastic acceleration and hadronic processes. The source was characterised by very uneven and erratic flaring activity in diverse epochs: the period of strong flares (2013–2016) was preceded by a moderate variability and followed by a gradual long-term decrease in MWL flaring activity. We detected a number of instances of intraday 0.3–10 keV variability, which were sometimes observed within a few hundred seconds and explained by the interaction between the relativistic shock front and jet inhomogeneities with strong magnetic fields. The X-ray and γ-ray fluxes showed a lognormal distribution, which hints at the imprint of accretion disc instabilities on the blazar jet.
Scattering parameters of a non-reciprocal magneto-optical integrated coupler used as an isolator
Authors: Boucher Yann G. , Dadoenkova Yuliya S. , Bentivegna Florian F. L.
Published: October 2022

We theoretically investigate a non-reciprocal magneto-optical integrated slab directional coupler. The scattering parameters of the structure are derived in the frame of the Coupled-Mode Theory (CMT). By properly designing the coupler, it is possible to achieve a perfect non-reciprocity (with 100% contrast) between the two directions of propagation. Other operating points can also be defined, especially since modal dispersion in the spectral domain is naturally taken into consideration.
Tantalum pentoxide micro-resonators for frequency comb generation
Authors: Daykin Jake , Woods Jonathan R C , Richardson Stephen C , Trojak Oliver J , Ayi-Yovo Folly Eli , Silver Jonathan M , Klokkou Nicholas T , Tong Amy S K , Gill Patrick , Politi Alberto , Horak Peter , Wilkinson James S , Apostolopoulos Vasilis
Published: October 2022

We present the design, fabrication, simulation and initial characterisation of tantalum pentoxide (Ta2O5) optical waveguides and micro-ring resonators for the purpose of supercontinuum and frequency comb generation. Spectral broadening results are presented for linear Ta2O5 waveguides for a range of central pump wavelengths between 900 nm and 1500 nm. These results are used as the basis for the dispersion engineering and development of Ta2O5 micro-ring resonators. The losses for sputtered and TEOS PECVD deposited SiO2 top cladded waveguides are characterised using a Fabry-Pérot loss measurement set-up. A solver based on the Lugiato-Lefever equation is presented and used to simulate the expected emission from the Ta2O5 micro-ring resonators. Promising initial experimental results show critical coupling and a Q-factor of 3.7×104.
Hybrid integration methodology for quantum cascade lasers with germanium waveguides in mid-IR
Authors: Mitchell Colin J. , Osman Ahmed , Li Ke , Penadés Jordi S. , Nedeljkovic Milos , Zhou Longqi , Groom Kristian M. , Heffernan Jon , Mashanovich Goran
Published: October 2022

Mid-infrared quantum cascade lasers (QCLs) operating around 5.7 μm have been integrated with germanium waveguides on silicon substrates. QCL bars have been designed and fabricated at the University of Sheffield for the purpose of integration. This hybrid approach uses flip-chip technology that has been successfully transferred from a silicon-on-oxide (SOI) platform working at communication wavelengths, demonstrating the flexibility of this approach. Integration challenges are introduced, and solutions discussed, leading to the next iteration of design presented here.
Sparse Mid-Infrared Spectra Enable Real-time and In-vivo Applications in Tissue Discrimination
Authors: Fischer Felix , Frenner Karsten , Herkommer Alois M.
Published: October 2022

Differentiation of malign and benign tissue based on spectral information can be done by only using a small fractional amount of the original mid-infrared spectrum. An optimally selected arrangement of a few narrow-band quantum cascade lasers provides proficient signal-to-noise ratios and can drastically reduce the data acquisition time with constant discriminability, such that real-time applications will be possible in short-term and in-vivo diagnostics in the long-term.
Extended field-of-view light-sheet microscopy
Authors: Vettenburg Tom
Published: October 2022

Light-sheet fluorescence microscopy enables rapid 3D imaging of biological samples. Unlike confocal and two-photon microscopes, a light-sheet microscope illuminates the focal plane with an objective orthogonal to the detection axis and images it in a single snapshot. Its combination of high contrast and minimal sample exposure make it ideal to image thick samples with sub-cellular resolution. To uniformly illuminate a wide field-of-view without compromising axial resolution, propagation-invariant light-fields such as Bessel and Airy beams have been put forward. These beams do however irradiate the sample with a relatively broad transversal structure. The fluorescence excited by the side lobes of Bessel beams can be blocked physically during recording; though at the cost of increased sample exposure. In contrast, the Airy beam has a fine transversal structure that is both curved and asymmetric. Its fine structure captures all the high-frequency components that enable high axial resolution without the need to discard useful fluorescence. This advantage does not carry over naturally to two-photon excitation where the fine transversal structure is suppressed. We demonstrate a symmetric and planar Airy light-sheet that can be used with two-photon excitation and that does not rely on deconvolution.
Ultra-short pulse laser-based fabrication process for lightweight structures in quartz glass applied for mirrors
Authors: Bischof David , Kahl Michael , Michler Markus
Published: October 2022

In the following work a manufacturing process for light weight structures in Fused Silica is presented. Such structures can potentially be used for mirrors to decrease the mass by simultaneously ensuring high stiffness. This talk should give the audience the possibility to assess the selective laser etching technology for mechanical structures in the field of optical mirrors.
Optical methods for measuring the feature size of optical diffraction gratings with nano-meter accuracy and implementation of suitable feedback control loops
Authors: Flügel-Paul Thomas , Heusinger Martin , Gerold Kristin , Szeghalmi Adriana , Zeitner Uwe
Published: October 2022

Surface relief diffraction gratings offer a high flexibility in their design and thus allow to synchronize their optical performance with the specific requirements of the underlying application. However, the accuracy and the specific control of the manufacturing processes are of vital importance. In this contribution, we present optical methods relying on white-light ellipsometry and how they can be exploited for the measurement of the critical dimensions of manufactured surface relief grating structures. We will furthermore present suitable processes (relying on atomic layer deposition) and how they are used in a feedback loop to control the grating’s feature sizes on the nanometer scale.
Optimization of grinding processes on fused silica components using in-process vibrometry and dynamometer measurements
Authors: Henkel Sebastian , Binder Marcel , Bliedtner Jens , Fritzsche Marco , Huseynov Abdulla , Schöneweck Franziska , Greiner-Adam Sascha , Flügge Jörg , Rädlein Edda
Published: October 2022

The presented investigations deal with real-time evaluation and recording of vibrations and forces during a CNC grinding process, as well as the analysis and control of process influences on the surface quality of optical components. The experiments were carried out on a 5-axis CNC machine. Rapid subsequent analysis of the topography resulting from grinding is achieved with the aid of white light interferometry. The aim of the investigations is to reduce the surface deviations (roughness, mid-spatials, waviness) influenced by process factors. It is shown that the vibration data measured during the grinding process correlate to a high degree with the recorded topography data.
Ray Transfer Matrix for Onion-Type GRIN Lenses
Authors: Lockett Veronica , Navarro Rafael , López Jose Luis
Published: October 2022

We present the computation of an ABCD matrix for onion-type GRIN lenses. By applying a differential approximation of the layer thickness, the matrix product of a high number of matrices is synthetized into a single matrix where the elements are integrals. The difference between this ABCD matrix and a homogeneous lens matrix is one integration term in element C, which is the GRIN contribution to the lens power. In the case of the crystalline lens, the analytical approximation to the GRIN lens power provides an accurate and concise solution in terms of Gaussian hypergeometric functions.
Enabling photonic system integration by applying glass based microelectronic packaging approaches
Authors: Schröder Henning , Lewoczko-Adamczyk Wojciech , Weber Daniel
Published: October 2022

Advanced hybrid packaging technologies are used to enhance functionality of glass-based substrates featuring electrical, thermal and optical components including laser diodes, modulators, isolators, photonic integrated circuits, beam-splitters and micro lenses. Such glass-based substrates can be either thin glass layers on large panels containing optical waveguides or more mini-bench-like boards. Optical fiber interconnects, plugs, and electrical-optical integration platforms are used for higher level system integration. We discuss thin glass as a suitable base material for ion exchanged waveguide panels and interposers, precise glass structuring for posts and holders, electrical wiring and the related high precision assembly techniques.
Investigations on the production of optical freeforms applying the advanced wheel polishing process
Authors: Stoebenau Sebastian , Morozov Igor , Hild Rafael , Henkel Sebastian , Schulze Christian , Letsch Christoph , Frank Samson , Bliedtner Jens
Published: October 2022

The growing interest in providing additional degrees of freedom to the design of high-end optical systems has led to an increased demand for freeform optical elements. The efficient fabrication of such elements requires a polishing process that provides high removal rates and a stable removal function while working with a relatively small spot size. Taking these constraints into consideration this paper focuses on the successful implementation of polishing processes applying the A-WPT (Advanced Wheel Polishing Tool) technology. Addressing the requirements regarding its removal characteristics as mentioned before, it represents an appropriate choice for providing an efficient pre-polishing as well as corrective polishing technique. In order to maintain perpendicularity towards the freeform surface to be polished, the A-WPT is run on a 5-axis simultaneous machining system. First investigations of the achieved surface accuracy after pre-polishing were carried out as well as an assessment of residual surface features within different spatial frequency regions. In addition, the polished surface is being checked for remaining SSD using an OCT technique.
Open-view Binocular Double-pass System for the Study of Dynamic Accommodation
Authors: Ávila Fracisco , Navarro Rafael , Safarian Baloujeh Ebrahim , Sánchez-Cano Ana
Published: October 2022

We present a new open-view dynamic double-pass (DP) system for the study of accommodative response in binocular natural viewing conditions. The DP point spread function (PSF) of the eye is analyzed to compute the Visual Strehl Ratio (VSR) fluctuation as a function of time at 50 Hz frame rate. Preliminary results showed that the proposed method can quantify the temporal dynamic of the optical and visual quality of both eyes simultaneously.
T-Matrix based Scattering Analysis of Photonic Materials with Periodicity in Different Dimensions
Authors: Beutel Dominik , Rockstuhl Carsten , Fernandez-Corbaton Ivan
Published: October 2022

Optical devices and artificial photonic materials frequently make use of periodic arrangements of identical scatterers in 3D, 2D, and 1D, e.g. photonic crystals, meta-surfaces, or particle chains. To simplify their analysis, we present here a computational framework based on the T-matrix method that explicitly exploits spherical, cylindrical, and plane waves depending on the geometry and number of dimensions of the lattice. Due to the analytic properties of the chosen basis sets in combination with the use of Ewald’s method for the lattice summation, we obtain an efficient framework to simulate such systems. The applicability will be illustrated at the conference by means of selected examples of contemporary interest.
Dynamics of the optical forces in nanosystems
Authors: Kiselev Andrei , Achouri Karim , Martin Olivier J. F.
Published: October 2022

We investigate optical forces in the time domain, instead of using the time-average Maxwell stress tensor. We demonstrate first that a plane wave causes on a physical object an optical pressure that fluctuates at optical frequency in the time domain. The analytical formula for the optical force dynamics is presented for this case. The case for two-wave illumination with slightly different frequencies is considered next. It is shown that in this case the optical force acquires a component at the beating frequency. The analytical expression for the transient force is deduced and its relation with average force explained in detail.
A rigorous computational framework employing coupled-mode theory for assessing lasing with transition metal dichalcogenide bilayers in the nanoscale
Authors: Nousios Georgios , Christopoulos Thomas , Zografopoulos Dimitrios C. , Kriezis Emmanouil E.
Published: October 2022

A whispering-gallery mode nanophotonic laser cavity having as active medium a transition-metaldichalcogenide (TMD) bilayer is examined. The proposed system is analysed and designed utilizing a strict and rigorous computational framework based on the coupled-mode theory. Our framework is capable of accurately and efficiently handling the gain properties of two-dimensional materials, such as contemporary TMD monolayers, multilayers, and heterostructures. The presented lasing cavity exhibits an adequately low pump threshold and light emission in the order of milliwatts is predicted. Exploiting the capabilities of the developed framework, we were in position to efficiently design the cavity as well as to estimate quantitative lasing parameters such as the pumping threshold and the lasing frequency.
Approaches for the RCWA-based non-destructive characterization of subwavelength-structured gratings
Authors: Wüster Julian , Reetz Andreas , Schmidt-Grund Rüdiger , Knauer Andrea , Sinzinger Stefan
Published: October 2022

Nano-structuring enables us to add additional degrees of freedom to the design of optical elements. Especially the possibility of controlling the polarization is of great interest in the field of nano-structured optics. For being able to exploit the whole range of form-birefringent phase shifts, the aspect ratios of the resulting element are typically much higher than the aspect ratios of conventional diffractive optical elements (DOEs), which does not only pose a challenge on fabrication but also on characterization. We evaluate several well-established approaches for the nondestructive characterization, including Müller-Matrix-Ellipsometry, measurement of the diffraction efficiencies, scattering measurements and calibration with rigorous coupled-wave modelling. The goal is to understand the challenges with all these techniques and combine them to a reliable method for structural reconnaisance of high aspect ratio nanostructures.
Simultaneous oscillation of dual optical parametric oscillators on monolithic chi(2) nonlinear photonic crystals
Authors: Chang Kai-Hsun , Fan Chia-Chun , Tsai Ming-Shung , Yang Fu-Hsiang , Mohand Ousaid Safia , Boudrioua Azzedine , Peng Lung-Han
Published: October 2022

Simultaneous oscillation of two pairs of signals and idlers was demonstrated. We also showed the efficiency of the sum frequency generation of two idlers was comparable with second harmonic generation of each idler. Our design shows the potential of building multi-wavelength laser source from UV to NIR on monolithic crystal.
Flexible all-glass planar structured fabricated by RF-sputtering
Authors: Carlotto Alice , Sayginer Osman , Szczurek Anna , Tran Lam T. N. , Dell’Anna Rossana , Varas Stefano , Babiarczuk Bartosz , Krzak Justyna , Bursi Oreste S. , Zonta Daniele , Lukowiak Anna , Righini Giancarlo C. , Ferrari Maurizio , Pietralunga Silvia M. , Chiasera Alessandro
Published: October 2022

Flexible SiO2/HfO2 1D photonic crystals and active SiO2–HfO2:Er3+ all-glass flexible planar waveguides fabricated by radio frequency sputtering, are presented. The 1D photonic crystals show a strong dependence of the optical features on the light incident angle: i) blue-shift of the stopband and ii) narrowing of the reflectance window. Nevertheless, the most interesting result is the experimental evidence that, even after the 1D photonic crystals breakage, where the flexible glass shows naked-eye visible cracks, the multilayer structures generally maintain their integrity, resulting to be promising systems for flexible photonic applications thanks to their optical, thermal and mechanical stability. The flexible planar waveguides, fabricated on ultrathin flexible glass substrate, showed an attenuation coefficient lower than 0.2 dB/cm at 1.54 μm, and exibits emission in the NIR region, resulting particularly suitable as waveguide amplifier in the C band of telecommunications.
Thermal effects reduction in a diode side-pumped rod-like bonded α-quartz||Nd:glass||α-quartz amplifying medium
Authors: Dubé Thomas , Camy Patrice , Montant Sébastien
Published: October 2022

We present a numerical study of a square-shape rod-like bonded laser gain medium operating at 1053 nm. The sample is composed of a 5-mm thick Nd-doped phosphate glass bonded to two α-quartz crystals. Owing to this face cooling scheme, the heat generated in the gain medium is effectively reduced, hence resulting in less optical distortions. The simulation of the thermomechanical effects was conducted using COMSOL MultiPhysics® software. Transverse wavefront distortion and birefringence profiles were computed for a given pump mean power. Wavefront and birefringence measurements will be conducted on the bonded sample using a pump-probe setup which is discussed in this paper. These measurements will be presented and weighed with the numerical results.
Laser-printed emissive metasurface implemented with a planar thin-film resonator
Authors: Lee Myeongkyu , Kim Yeongseon , Kang Dongkyun , Kim Jaeyong
Published: October 2022

Optical security is a promising application of metasurfaces because light has large degrees of freedom in metasurfaces. Although many different structures/materials have been proposed for this purpose, the fabrication of dynamic metasurfaces in a straightforward and scalable manner while maintaining a high security level remains a significant challenge. Herein, a metasurface consisting of a phase-changing Ge2Sb2Te5 (GST) layer and a thin metal back reflector is presented to space-selectively and dynamically control the infrared emission of the surface by a spatially modulated pulsed laser beam. Unlike conventional laser processes using a focused beam, the employed laser printing is an expanded beam-based parallel process that enables the fabrication of wafer-sized emission patterns. Owing to the multispectral responses of GST, mutually independent visible and infrared images can be printed in one region. Grayscale emission patterns can also be obtained by gradually modulating the spatial profile of the laser beam, which makes the replication of laser-printed emission patterns extremely difficult. These encouraging features are experimentally verified using rigid and flexible substrates, indicating that the presented emissive metasurface has the potential for use as an effective platform for anti-counterfeiting.
Thermal radiation in dipolar many-body systems
Authors: Biehs Svend-Age
Published: October 2022

The framework of fluctuational electrodynamics for dipolar many-body systems is one of the working horse for theoretical studies of thermal radiation at the nanoscale which includes dissipation and retardation in a naturally way. Based on this framework I will discuss near-field thermal radiation in non-reciprocal and topological many-body systems. The appearance of the Hall and non-reciprocal diode effect for thermal radiation illustrates nicely the interesting physics in such systems as well as the edge mode dominated heat transfer in topological Su-Schrieffer-Heeger chains and a honeycomb lattices of plasmonic nanoparticles. In the latter, the theory allows for quantifying the effciency of the edge-mode dominated heat transfer as function of the dissipation. Finally, I will present how the theoretical framework can be generalized to study far-field thermal emission of many-body systems close to an environment like a substrate, for instance. This theory might be particularly interesting for modelling thermal imaging microscopes.
Enhancing the solar-to-thermal energy conversion in high vacuum flat plate solar collectors
Authors: Russo Roberto , De Maio Davide , D’Alessandro Carmine , De Luca Daniela , Caldarelli Antonio , Gaudino Eliana , Musto Marilena , Di Gennaro Emiliano
Published: October 2022

In solar flat plate collectors, the high vacuum insulation suppresses the convective losses increasing the collector efficiency. The solar-to-thermal energy conversion efficiency in such solar thermal collectors is mainly defined by the optical and radiation losses of the selective solar absorber. We present the full process of design, optimization, fabrication, and characterization of multilayer coatings specifically thought for working in high vacuum flat solar thermal collectors at different operating temperatures, from 100 °C to 300 °C. We discuss the relative importance of absorptance and emittance in determining the collector thermal efficiency. The robustness of the performance of the coatings related to the unpreventable errors in layer thickness during the manufacturing stage is also considered through a genetic optimisation algorithm.
Fourier-limited attosecond pulse generation with magnetically pumped high-order harmonic generation
Authors: Martín-Hernández Rodrigo , Plaja Luis , Hernández-García Carlos
Published: October 2022

After more than two decades of attosecond physics, the generation and control of the shortest laser pulses available remains as a complex task. One of the main limitations of reducing the temporal duration of attosecond pulses emitted from high-order harmonic generation (HHG) is the attochirp. In this contribution, we demonstrate that HHG assisted by strong fast oscillating magnetic fields enables the generation of Fourierlimited attosecond pulses in the water window. In short, the magnetic field generates a nanowire-like structure, which transversally confines the electronic wavefunction in the HHG process. We demonstrate that the resulting HHG spectrum extends well beyond the semiclassical cutoff frequency, and most interestingly, it is emitted in the form of few-cycle, Fourier-limited, attosecond pulses.
Static Multi-Vortex Structures in Nonlinear Optical Media
Authors: Paredes Angel , Salgueiro José Ramón , Michinel Humberto
Published: October 2022

We demonstrate through numerical simulations the existence of a new type of nonlinear waves in optical media: structures of vortex solitons that remain static in certain configurations, which depend on their relative positions and topological charges. Several examples are presented to illustrate this surprising behavior.
Multi-beam vortex generation induced by the non-linear optical anisotropy of graphene
Authors: Plaja Luis , García-Cabrera Ana , Boyero-García Roberto , Zurrón Óscar , San Román Julio , Hernández-García Carlos
Published: October 2022

We analyse the high harmonic emission from single-layer graphene driven by infrared vector beams. We demonstrate that graphene’s anisotropy offers a privileged scenario to explore non-trivial light spin-orbit couplings, which substantially extends the possibilities for the generation of high-harmonic structured beams currently studied in atomic and molecular targets. In our case, graphene’s crystal symmetry introduces a spin-dependent diffraction pattern that, coupled with the fundamental conservation of the driver’s topological phase, leads to the splitting of the harmonic field in a multi-beam structure, composed of spatially diverging vortices. Our work demonstrates that anisotropic targets are extraordinary tools to sculpt complex structured short-wavelength beams.
Non-locality and single meta-atom spectroscopy in THz Landau polaritons
Authors: Scalari Giacomo , Rajabali Shima , Jöchl Elsa , Markmann Sergej , de Liberato Simone , Cortese Erika , Beck Mattias , Faist Jérôme
Published: October 2022

We will discuss, theoretically and experimentally, the existence of a limit to the possibility of arbitrarily increasing electromagnetic confinement in polaritonic systems, where strongly sub-wavelength fields can excite a continuum of high-momenta propagative magnetoplasmons. This leads to peculiar nonlocal polaritonic effects, as certain polaritonic features disappear and the system enters in the regime of discrete-to-continuum strong coupling. We will as well present experiments reporting spectroscopy of a single, ultrastrongly coupled, highly subwavelength resonator operating at 300 GHz.
Light propagation in disordered aperiodic Mathieu photonic lattices
Authors: Vasiljević Jadranka M. , Timotijević Dejan V. , Jović Savić Dragana M.
Published: October 2022

We present the numerical modeling of two different randomization methods of photonic lattices. We compare the results of light propagation in disordered aperiodic and disordered periodic lattices. In disordered aperiodic lattice disorder always enhances light transport for both methods, contrary to the disordered periodic lattice. For the highest disorder levels, we detect Anderson localization for both methods and both disordered lattices. More pronounced localization is observed for disordered aperiodic lattice.