Polar Components Research Articles

Significant improvement of chaotic synchronization quality of two polarization components emitted by an optically pumped spin- VCSEL using wavelet decomposition in photonic reservoir computers

Based on Daubechies (db) wavelet decomposition method, we propose to use the double photonic reservoir computers to enhance the chaotic synchronization quality of the two polarization components (X-PC and Y-PC) emitted by an optically pumped spin-VCSEL (the drive-VCSEL). The chaotic time series of two polarization components (PCs) from the drive-VCSEL, which serve as predictive targets, are decomposed into high-frequency and low-frequency components (multi-scale time series). This decomposition is performed using the first-type of Daubechies wavelet (db1-wavelet) decomposition. Our findings demonstrate that contrasted with a direct-prediction approach , the predictive errors in various intricate chaotic dynamics of the targets, outlined by permutation entropy, can be substantially minimized through db1-wavelet decomposition. As the layer number of the db1-wavelet decomposition increases, it noteworthily reduces the error in their predictive outcomes. Furthermore, under different parameter spaces, db1-wavelet decomposition considerably reduces the prediction errors for the targets and greatly enhances the quality of chaotic synchronization between pairs of X-PCs or Y-PCs, which are from the drive-VCSEL and reservoir-VCSEL. The further increase of the layer number of the db1-wavelet decomposition can trigger a more significant reduction in the prediction errors and improves the quality of chaotic synchronization. Interestingly, the use of different types of Daubechies wavelet decompositions does not substantially impact the prediction errors or the quality of chaotic synchronization. Our proposed model effectively addresses the issue of multi-scale optical time series prediction. The findings of this study can potentially be applied in enhancing the quality of optical chaotic synchronization in a photonic reservoir computing system.

Evidence for bipolar explosions in Type IIP supernovae

Aims. Recent observations of core-collapse supernovae (SNe) suggest aspherical explosions. Globally, aspherical structures in SN explosions are thought to encode information regarding the underlying explosion mechanism. However, the exact explosion geometries from the inner cores to the outer envelopes are poorly understood. Methods. Here, we present photometric, spectroscopic, and polarimetric observations of the Type IIP SN 2021yja and discuss its explosion geometry in comparison to those of other Type IIP SNe that show large-scale aspherical structures in their hydrogen envelopes (SNe 2012aw, 2013ej and 2017gmr). Results. During the plateau phase, SNe 2012aw and 2021yja exhibit high continuum polarization characterized by two components with perpendicular polarization angles. This behavior can be interpreted as being due to a bipolar explosion, where the SN ejecta is composed of a polar (energetic) component and an equatorial (bulk) component. In such a bipolar explosion, an aspherical axis created by the polar ejecta would dominate at early phases, while the perpendicular axis along the equatorial ejecta would emerge at late phases after the photosphere in the polar ejecta has receded. Our interpretation of the explosions in SNe 2012aw and 2021yja as bipolar is also supported by other observational properties, including the time evolution of the line velocities and the line shapes in the nebular spectra. The polarization of other Type IIP SNe that show large-scale aspherical structures in the hydrogen envelope (SNe 2013ej and 2017gmr) is also consistent with the bipolar-explosion scenario, although this is not conclusive.

Soliton in parity-time optical lattice with pseudo spin-orbit coupling

We investigated the existence and stability of solitons in parity-time optical lattice with pseudo spin-orbit coupling (SOC). The numerical results show that the symmetry of solitons still accords with the characteristics of traditional parity-time (PT) soliton symmetry. Due to the existence of PT optical lattice, the polarization component of solitons is not purely real or purely imaginary. And the strength of SOC has a significant impact on the band-gap structure of the system.

Multi-mode coupling in a H-shaped metamaterial structure in terahertz frequency

Mode coupling can not only effectively control the frequency, amplitude and linewidth of the transmission spectrum, but also improve the Q-factor of the spectrum. Herein, we propose a H-shaped metamaterial, in which the dipole mode, LC mode and lattice mode can be excited selectively, and each mode frequency can be independently tuned by changing the polarization of incident THz wave as well as the lattice constant of the metamaterial structure, thus allowing greater degrees of freedom to customize the polarization components of different properties in the system. Under different polarization directions, the strong coupling between the lattice mode and the inductance-capacitance (LC) mode as well as the lattice mode and the dipole mode is realized, which makes the transmission resonance Q-factor of the hybrid state increase to 8 times that of the single resonance state, and the obvious anti-crossing phenomenon is observed. In addition, the LC mode and the dipole mode can be excited simultaneously, and the coupling between these two modes successfully excites a bound states in the continuum with an infinite Q-factor.

An investigation toward adhesion characteristics of emulsified asphalt residue–aggregate interface through MD simulation

The bonding ability of emulsified asphalt residue-aggregate interface is crucial for improving the pavement performance of emulsified asphalt mixtures. The aim of the study was to explore the adhesion mechanism and characteristics of emulsified asphalt residue-aggregate interface under the different emulsifier contents using molecular dynamics (MD) simulation. Firstly, the emulsified asphalt residue-aggregate interface model was established, and its validity was validated through the related thermodynamic properties. Secondly, the performance-related parameters were employed to discuss the molecular arrangement features of emulsified asphalt residue components on the aggregate surface, and investigate the interfacial adhesion mechanism. Thirdly, the adhesion strength of emulsified asphalt residue-aggregate interface was calculated and evaluated by the adhesion energy. Lastly, the influence of temperature and moisture on the interfacial adhesion strength was further examined through the molecular orientation theory and the electrostatic interaction theory. The results indicate that the addition of emulsifiers could affect the aggregation behaviors and distribution characteristics of asphalt components as observed from performance-related parameters. When compared to relatively high emulsifier content (4–6 %), the molecular arrangement of emulsified asphalt residue components with relatively low emulsifier content (1–3 %) is more similar to that of the base asphalt and exhibits greater interfacial adhesion strength with aggregates. The polar components and emulsifiers in emulsified asphalt residue with relatively low emulsifier content are minor affected by the increase of temperature, which further proving that interfacial adhesion strength is higher at this condition. Meanwhile, emulsified asphalt residue with relatively low emulsifier content is confirmed to have better moisture damage resistance due to the existence of the certain number of Silica-Water(S-W) and Asphalt-Water(A-W) hydrogen bonds near interface. Moisture exhibits more significant influence on the interfacial adhesion strength between emulsified asphalt residue and aggregates according to the results of the average adhesion energy. It is advisable to apply emulsified asphalt with moderate emulsifier content during the actual production process considering the influence of moisture and temperature on the pavement performance of emulsified asphalt mixtures.

Non-mechanical steering of the optical beam in spectral-domain optical coherence tomography

We demonstrate in a proof-of-concept experiment spectral-domain optical coherence tomography where steering of the optical beam that probes the sample in a transverse scan does not make use of any mechanical element. Steering is done with the help of a phase-only spatial light modulator, that introduces a spatially-dependent phase between the two orthogonal polarization components of an optical beam, and some optical elements that control the polarization of light. We demonstrate that making use of the non-mechanical beam steering system considered here, we can reproduce the main traits of imaging with standard OCT that makes use of mechanical-assisted optical beam steering.

Second Harmonic Generation of Twisted Vector Vortex Beams Using aβ-BaB2O4 Crystal

In this study, we demonstrate both theoretically and experimentally second harmonic generation (SHG) of a twisted vector vortex optical field (TVVOF) using a nonlinear type-II phase-matched β-BaB2O4 (BBO) crystal. Our study introduces a novel method to manipulate SHG by independently modulating the two orthogonal polarization components of a TVVOF. This flexibility in controlling SHG can be achieved through accurate experimental adjustments of the polarization components. Furthermore, we reveal that the SHG can be dynamically tuned by varying the angle between the polarization direction of the optical field and the principal axis of the BBO crystal via rotation. These findings provide a new approach for the flexible manipulation of SHG in structured vector optical fields, which have potential applications in optical communication, quantum optics, and photonic device engineering.

Tau polarization in neutrino-nucleus interactions at the LHC energy range

Considering that the study of neutrino-nucleus interactions with incident neutrino energy ranges in the GeV–TeV range is feasible at the Large Hadron Collider, we investigate in this paper the degree of polarization P of the (anti)tau lepton produced in (anti)tau neutrino-tungsten interactions. We estimate the differential cross sections and the longitudinal and transverse components of the tau lepton polarization as a function of the tau lepton energy and distinct values of the scattering angle, assuming different values for the energy of the incoming (anti)tau neutrino. Different models for the treatment of the nuclear effects in the parton distribution functions are assumed as input in the calculations. Our results indicate that P<1 for the neutrino energies reached at the LHC and are almost insensitive to the nuclear effects. Published by the American Physical Society 2024

Radiative corrections to the muon polarization in the semileptonic decay of a neutral kaon

A model-independent expression for the Dalitz plot of the semileptonic decays of a neutral kaon Kμ30\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {K}_{\\mu 3}^0 $$\\end{document}, including radiative corrections to order O\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{O} $$\\end{document}[(α/π)(q/M1)], where q is the four-momentum transfer and M1 is the mass of the decaying kaon, is presented. In this paper the emitted muon is considered to be polarized so the analysis is centered on numerically evaluating the radiative corrections to the longitudinal, transverse, and normal polarization muon components. The model dependence of radiative corrections is kept in general form within this approximation, which is useful for model-independent experimental analyses. The final expressions, with the triple integration of the bremsstrahlung photon variables are ready to be evaluated numerically, they are free of the infrared divergence or ultraviolet cutoff. The radiative corrections to the components of the muon polarization are found to be very small compared to their respective uncorrected values.

Characterization of the polarization state of few-cycle laser pulses using d-scan: D-TURTLE

We characterize the polarization state of few-femtosecond laser pulses by implementing the dispersion scan technique in combination with the tomographic ultrafast retrieval of transverse light E-fields procedure (D-TURTLE). We demonstrate, both numerically and experimentally, that D-TURTLE unambiguously identifies the pulse ellipticity, its handedness and which polarization component travels ahead. Given the robustness of this technique, and its self-referenced and in-line nature, D-TURTLE can be extremely useful to characterize polarized few-cycle laser pulses.

Impedance Inhomogeneity in SiO/Gr Composite Anode

Silicon/carbon (Si/C) composite anode materials have emerged as promising candidates for high‐energy‐density lithium‐ion batteries (LIBs), boasting advantages such as high capacity, cost‐effectiveness, and abundance. However, the integration of Si‐based materials into conventional graphite anodes introduces heterogeneous interactions between electrochemical and mechanical behaviors, owing to substantial volume changes and chemical potential variations. One significant consequence of these interactions is the impedance inhomogeneity, which adversely affects the discharging capacity of Si‐based LIBs. In an effort to comprehensively understand this phenomenon and its underlying mechanisms, an electrochemo‐mechanical‐coupled model is established, incorporating detailed particle geometries on the anode side. The model is employed to investigate polarization components and their evolution during the charging/discharging process. Various influencing factors, such as SiO weight percentage (wt%), electrode thickness, and SiO distributions (both in terms of distribution uniformity and direction), are systematically discussed. In this study, an efficient computational approach is offered to analyze battery polarizations, deepening the understanding of the inhomogeneous evolution of these polarizations in Si/C composite anodes. Ultimately, these insights guide the design of anodes for next‐generation high‐energy‐density LIBs.

Comparative study of surface preparation for paint adhesion on CF-PEKK composites: Plasma, Chemical, and Flame treatment

Polyether ketone-ketone (PEKK) is a high-performance thermoplastic, and its fiber composites have various engineering applications. Fiber reinforced composites in long-term applications require a protective layer of coatings to avoid environmental degradation. In this work, the surface energy of carbon fiber-PEKK composites was modified by flame, chemical, and plasma treatments to improve paint adhesion. A detailed study was carried out to understand the physical, morphological, and chemical surface characteristics due to different surface treatments. We found through XPS that highly active surface functionalities (− C-Ȯ/−C = Ȯ) due to oxidation at the ketone/ether groups were for surface adhesion. In support of the enhanced surface functionality, we have also evaluated the wetting behavior of paint with respect to different treated surfaces using drop shape analyzer and found that the polar component of the surface free energy increased for all treatments compared to pristine. Surface crystallinity after surface treatment was assessed using XRD; flame and plasma showed reduced surface crystallinities (25.92 % and 38.18 %, respectively), compared to pristine (46.78 %), and yielded a good adherend for coatings. Surfaces with good wettability and functionalities show good adhesion between the paint and PEKK composites as found through adhesion tests following ASTM D3359. The findings demonstrate that plasma surface treatment outperformed flame and chemical treatments in terms of adhesion of the paint to the surface.

Double Hanle resonance dependence on light polarization angle and transverse magnetic field direction

We present experimental and theoretical investigations of the dependence of double Hanle resonance spectrum on the light polarization angle and the direction of the applied transverse magnetic field (TMF). The experiments are done for Fg=2→Fe=1 transition of 87Rb D1 line using a rubidium vapor cell containing buffer gas. We show that a small light polarization component along the direction of TMF introduces asymmetry in the double Hanle resonance signal. Both the magnitude and sign of asymmetry in the signal are sensitive to the TMF orientation, suggesting a possible method for in-situ measurement of the direction of the magnetic fields generated by the coils. The physical origin of this asymmetry is explained by considering the redistribution of population among the ground-state Zeeman sublevels in the presence of TMF. In addition, we systematically vary both the polarization angle and TMF direction to study their effect on the line profile of Hanle resonances. We demonstrate that a double Hanle resonance changes to a dark Hanle resonance by rotating the light polarization vector irrespective of the TMF direction. We have developed a simple theoretical model based on a degenerate two-level system to explain our experimental observations.

Prenatal Immune Challenge Differentiates the Effect of Aripiprazole and Risperidone on CD200-CD200R and CX3CL1-CX3CR1 Dyads and Microglial Polarization: A Study in Organotypic Cortical Cultures.

Microglia are the primary innate immune cells of the central nervous system and extensively contribute to brain homeostasis. Dysfunctional or excessive activity of microglia may be associated with several neuropsychiatric disorders, including schizophrenia. Therefore, we examined whether aripiprazole and risperidone could influence the expression of the Cd200-Cd200r and Cx3cl1-Cx3cr1 axes, which are crucial for the regulation of microglial activity and interactions of these cells with neurons. Additionally, we evaluated the impact of these drugs on microglial pro- and anti-inflammatory markers (Cd40, Il-1β, Il-6, Cebpb, Cd206, Arg1, Il-10 and Tgf-β) and cytokine release (IL-6, IL-10). The research was executed in organotypic cortical cultures (OCCs) prepared from the offspring of control rats (control OCCs) or those exposed to maternal immune activation (MIA OCCs), which allows for the exploration of schizophrenia-like disturbances in animals. All experiments were performed under basal conditions and after additional stimulation with lipopolysaccharide (LPS), following the "two-hit" hypothesis of schizophrenia. We found that MIA diminished the mRNA level of Cd200r and affected the OCCs' response to additional LPS exposure in terms of this parameter. LPS downregulated the Cx3cr1 expression and profoundly changed the mRNA levels of pro- and anti-inflammatory microglial markers in both types of OCCs. Risperidone increased Cd200 expression in MIA OCCs, while aripiprazole treatment elevated the gene levels of the Cx3cl1-Cx3cr1 dyad in control OCCs. The antipsychotics limited the LPS-generated increase in the expression of proinflammatory factors (Il-1β and Il-6) and enhanced the mRNA levels of anti-inflammatory components (Cd206 and Tgf-β) of microglial polarization, mostly in the absence of the MIA procedure. Finally, we observed a more pronounced modulating impact of aripiprazole on the expression of pro- and anti-inflammatory cytokines when compared to risperidone in MIA OCCs. In conclusion, our data suggest that MIA might influence microglial activation and crosstalk of microglial cells with neurons, whereas aripiprazole and risperidone could beneficially affect these changes in OCCs.

Optimization of SLIPI–polarization ratio imaging for droplets sizing in dense sprays

In this article, structured laser illumination planar imaging and polarization ratio techniques are successfully combined to size droplets in various optically dense sprays. The polarization ratio approach is based on the acquisition of the perpendicular and parallel polarized components of Lorenz–Mie scattered light, for which the ratio is proportional to the surface mean diameter, D21. One of the main advantages of this technique, compared to some other laser imaging techniques for particle sizing, is that no fluorescent dye is required. This makes the technique suitable for characterizing sprays under evaporation conditions, such as combustion or spray drying applications. In addition, the SLIPI technique aims at suppressing the detection of multiple light scattering and at extracting the desirable single-light scattering signal. To test the reliability of this novel approach, an industrial hollow-cone nozzle is used, injecting at 50 bar water mixed with Glycerol (in the range of 0–60%). The first aim of this work is to study the experimental parameters that influence the reliability of the technique, such as the polarization orientation of the incident light, the refractive index of the injected liquid and the variation of the droplet size distribution. Using Phase Doppler Anemometry, the results show that a linear calibration is obtained for droplets ranging between 10 and 70 μm, when the incident illumination has a polarization set to 10° and 20°. In addition, this article demonstrates the feasibility of the technique for the measurement of liquids having a refractive index reaching 1.41. In the last stage of this work, after rotating the nozzle every 5°, a 3D tomographic reconstruction of D21 is performed. This demonstrates the robustness and efficiency of the technique for droplet sizing in 3D, under challenging conditions.

Phase retrieval in inverse ghost diffraction using Sagnac interferometer

Ghost diffraction (GD) involves the use of non-local spatial correlations to image objects with light, which has not interacted with them. Here, we propose and experimentally demonstrate a new technique for first-order correlation measurement and retrieval of two-dimensional phase objects in the GD from inversion of the experimentally measured two-point complex correlation function in a first order interferometer. The GD scheme is experimentally implemented by a specially designed experimental setup wherein one of the orthogonal polarization components of the transversely polarized light interacts with the object and the other polarization component of the light remains intact and directly reaches the detector. The Fourier spectrum of the object is encoded into the two-point spatial correlation of these two orthogonal polarization components which is experimentally detected in an interferometer with a radial shearing in the Sagnac geometry. We experimentally demonstrated imaging of spatially varying phase objects and results are presented for three different cases.

Surface modeling of wettability transition on α-quartz: Insights from experiments and molecular dynamics simulations

The wettability of quartz surfaces is a critical property in numerous energy-related industrial processes. However, accurately quantifying wettability is challenging due to the multitude of factors that can influence wetting behavior. Herein, we proposed a generalized surface modeling procedure addressing microscopic insights to calculate the contact angles of liquids on quartz under different scenarios. An optical goniometer experimentally measured the contact angles and validated the proposed surface modeling procedure. The effects of surface density of hydroxyl groups, temperature, surfactants, and crude oil composition on the wettability of quartz surfaces were studied. The results revealed that an increased hydroxyl group density significantly improved water wettability on a quartz surface. An increased temperature reduced the water contact angle on quartz, and such decreasing rates became steeper at high temperatures. The surfactants’ adsorption morphology determined the wettability of a quartz surface. Moreover, the polar components in crude oil significantly increased the hydrophobicity of a quartz surface, making it easier to adsorb more oil molecules to alter the quartz wettability further. The valuable outcomes of this paper contribute to understanding the complex quartz wettability and pave the way for further studies involving quartz surface modeling.

Influence of Stress on the Chiral Polarization and Elastrocaloric Effect in BaTiO3 with 180° Domain Structure

The polarization and elastrocaloric effect of chiral barium titanate (BaTiO3) with an Ising–Bloch-type domain wall under stress was investigated using the Landau–Ginzburg–Devonshire (LGD) theory. It has been shown that tensile stresses increase the magnitude of the Ising polarization component in barium titanate, together with a decrease in the domain wall width. Compressive stresses cause a reduction in the Ising polarization component and an increase in the domain width. Under compressive stress, barium titanate exhibits a negative elastrocaloric effect and temperature changes with increasing stress, while BaTiO3 exhibits a positive elastrocaloric effect under tensile stress. Bloch polarization shows angle-dependent polarization under external force, but the temperature change from the elastrocaloric effect is smaller than that of Ising polarization under stress. This work contributes to the understanding of polarization evolution under tension in ferroelectrics with chiral structure.

Influence of acidity and alkalinity of water environment on water stability of asphalt mixture: Phase II-microscopic erosion mechanism

Acidity and alkalinity of water environments have been proven to influence the water stability of asphalt mixture. However, the relevant influencing mechanism still remains unclear. To fulfill this research gap, this study conducted a series of microscopic tests, aiming at unveiling the microscopic erosion mechanism of the water environment on the water stability of asphalt mixture for better moisture stability achieved. Specifically, the asphalt-aggregate interfacial transition zone (ITZ) samples were prepared by combining #70 asphalt with limestone and granite, respectively, which were then immersed in water solutions at 3 different pH levels (pH = 3.0, 7.0, and 11.0) for 7 days. The chemical composition and microstructure of the asphalt film on the surface of the ITZ samples pre and post-treatment were scrutinized using the Fourier Transform Infrared Spectroscopy (FTIR) and the Atomic Force Microscope (AFM), while the development of microcracks at the asphalt-aggregate interface were identified and traced utilizing the Scanning Electron Microscope (SEM). The test results indicate that after treatment with acidic and alkaline aqueous solutions, the asphalt film's surface is enriched with polar components such as asphaltenes, resins, and aromatic fractions. The migration of these polar components to the surface of the asphalt film reduces the adhesion between asphalt-aggregate, leading to the formation of microcracks at the asphalt-aggregate interface. The most severe crack development occurs in alkaline water environment, followed by acidic water environment. It is interestingly noted that the adhesion at the asphalt-granite interface is improved under the acidic environment. This improvement may be attributed to the covalent nature of silica, which hinders the adsorption of ions from acidic solution into the asphalt film. This hindrance effectively prevents water intrusion at the asphalt-aggregate interface, thereby reducing the adhesion loss. These findings can help elucidate the mechanism of water damage in asphalt pavement exposed to real-world conditions and enhance its water stability with effective countermeasures proposed.

Polarization-resolved near-field characterization of coupling between a bus waveguide and a ring resonator

Light propagation in Photonic integrated circuits (PICs), which can nowadays involve complex systems of light-guiding structures, is measured with different approaches(Nuzhdin et al., 2020, Lončar et al., 2002, Hopman et al., 2007, Morichetti et al., 2014, Sapienza et al., 2012, Vesseur et al., 2007). An interferometric polarization-sensitive measurement of the evanescent fields of these structures provides insight in the performance of the circuit detects possible malfunction with sub-wavelength precision(Engelen et al., 2007, Gersen et al., 2005, Barwick et al., 2009). We demonstrate a Near-field scanning optical microscopy (NSOM) measurement on coupled ring resonators that shows how the guided modes evolve as they propagate across the optical chip. Analysis of the measurements provides information about intensity distribution of the two polarization components (TE and TM) and their spatial confinement. The data validates our methodology and opens new possibilities for analysis of signal propagation in prototyping and optimization of integrated optical systems. Direct observation of polarization state of the guided modes allows for clear understanding of mode conversion in coupling systems.