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Jul 2023 • APL Photonics

Opto-mechanical fiber sensing with optical and acoustic cladding modes

Avi Zadok, Elad Zehavi, Alon Bernstein

Optical fibers are an excellent sensor platform. However, the detection and analysis of media outside the cladding and coating of standard fibers represent a long-standing challenge: light that is guided in the single optical core mode does not reach these media. Cladding modes help work around this difficulty, as their transverse profiles span the entire cross-section of the fiber cladding and reach its outer boundary. In this tutorial, we introduce and discuss in detail two recent advances in optical fiber sensors that make use of cladding modes. Both concepts share optomechanics as a common underlying theme. First, we describe a spatially continuous distributed analysis using the optical cladding modes of the fiber. Light is coupled to these modes using Brillouin dynamic gratings, which are index perturbations associated with acoustic waves in the core that are stimulated by light. Unlike permanent gratings, which …

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Jul 2023

High-resolution computed tomography with scattered X-ray radiation and a single pixel detector

Sharon Shwartz, Adi Ban Yehuda, Or Sefi, Yishay Klein, Rachel Shukrun, Hila Schwartz, Eliahu Cohen

X-ray imaging is a prevalent technique for non-invasively visualizing the interior of the human body and opaque instruments. In most commercial X-ray modalities, an image is formed by measuring the X-rays that pass through the object of interest. However, despite the potential of scattered radiation to provide additional information about the object, it is often disregarded due to its inherent tendency to cause blurring. Consequently, conventional imaging modalities do not measure or utilize these valuable data. In contrast, we propose and experimentally demonstrate a high-resolution technique for X-ray computed tomography (CT) that measures scattered radiation by exploiting computational ghost imaging (CGI). We show that our method can provide sub-200 µm resolution, exceeding the capabilities of most existing X-ray imaging modalities. Our research reveals a promising technique for incorporating scattered radiation data in CT scans to improve image resolution and minimize radiation exposure for patients. The findings of our study suggest that our technique could represent a significant advancement in the fields of medical and industrial imaging, with the potential to enhance the accuracy and safety of diagnostic imaging procedures.

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Jul 2023 • Laser & Photonics Reviews

Deep-Subwavelength Resonant Meta-Optics Enabled by Ultra-High Index Topological Insulators

Singh, D., Nandi, S., Fleger, Y., Cohen, S. Z., Lewi, T.

In nanophotonics, small mode volumes, high‐quality factor resonances, and large field enhancements without metals fundamentally scale with the refractive index and are key for many implementations involving light‐matter interactions. Topological insulators (TIs) are a class of insulating materials that host topologically protected surface states, some of which exhibit extraordinarily high permittivity values. Here, the optical properties of TI bismuth telluride (Bi2Te3) single crystals are studied. It is found that both the bulk and surface states contribute to the extremely large optical constants, with the real part of the refractive index peaking at n ≈ 11. Utilizing these ultra‐high index values, it is demonstrated that Bi2Te3 metasurfaces are capable of squeezing light in deep‐subwavelength structures, with the fundamental magnetic dipole (MD) resonance confined in unit cell sizes smaller than λ/10. It is further shown that …

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Jul 2023 • Electrochimica Acta

Advanced impedance analysis of direct quinone fuel cells using distribution of relaxation times

Yan Yurko, Lior Elbaz

The need for new, reliable, and sustainable energy sources led to the development of new types of fuel cells. Fuel cells that rely on liquid hydrogen carriers may be the ultimate solution to the expensive hydrogen logistics issues. In this category, direct quinone fuel cells (DQFCs) are a promising new technology that solves many of the issues of traditional fuel cells. As a new technology, DQFCs need to be studied thoroughly to reach their full potential. Here, we use a distribution of relaxation times (DRT) analysis to analyze the impedance data of DQFCs, to gain a better understanding of the system. We systematically changed the operating parameters and attributed the changes in the DRT spectra to the physical processes they correspond to. The four main peaks observed in the DRT measurements were assigned to oxygen reduction reaction (ORR), quinone diffusion resistance, proton diffusion in the membrane …

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Jul 2023 • The Journal of Chemical Physics

Temperature-dependence of the chirality-induced spin selectivity effect—Experiments and theory

Seif Alwan, Subhajit Sarkar, Amos Sharoni, Yonatan Dubi

The temperature-dependence of the chirality-induced spin selectivity (CISS) effect can be used to discriminate between different theoretical proposals for the mechanism of the CISS effect. Here, we briefly review key experimental results and discuss the effect of temperature in different models for the CISS effect. We then focus on the recently suggested spinterface mechanism and describe the different possible effects temperature can have within this model. Finally, we analyze in detail recent experimental results presented in the work of Qian et al.[Nature 606, 902–908 (2022)] and demonstrate that, contrary to the original interpretation by the authors, these data actually indicate that the CISS effect increases with decreasing temperature. Finally, we show how the spinterface model can accurately reproduce these experimental results.

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Jul 2023 • Nature Communications

A sodium-ion-conducted asymmetric electrolyzer to lower the operation voltage for direct seawater electrolysis

Hao Shi, Tanyuan Wang, Jianyun Liu, Weiwei Chen, Shenzhou Li, Jiashun Liang, Shuxia Liu, Xuan Liu, Zhao Cai, Chao Wang, Dong Su, Yunhui Huang, Lior Elbaz, Qing Li

Hydrogen produced from neutral seawater electrolysis faces many challenges including high energy consumption, the corrosion/side reactions caused by Cl-, and the blockage of active sites by Ca2+/Mg2+ precipitates. Herein, we design a pH-asymmetric electrolyzer with a Na+ exchange membrane for direct seawater electrolysis, which can simultaneously prevent Cl- corrosion and Ca2+/Mg2+ precipitation and harvest the chemical potentials between the different electrolytes to reduce the required voltage. In-situ Raman spectroscopy and density functional theory calculations reveal that water dissociation can be promoted with a catalyst based on atomically dispersed Pt anchored to Ni-Fe-P nanowires with a reduced energy barrier (by 0.26 eV), thus accelerating the hydrogen evolution kinetics in seawater. Consequently, the asymmetric electrolyzer exhibits current densities of 10 mA cm−2 and 100 mA cm …

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Jul 2023 • Electrochimica Acta

First isolation of solvated MgCl+ species as the sole cations in electrolyte solutions for rechargeable Mg batteries

Ananya Maddegalla, Yogendra Kumar, Sankalpita Chakrabarty, Yuri Glagovsky, Bruria Schmerling, Natalia Fridman, Michal Afri, Hagit Aviv, Doron Aurbach, Ayan Mukherjee, Dmitry Bravo-Zhivotovskii, Malachi Noked

Synthesis of complex magnesium cations in ethereal solutions, is receiving a lot of attention due to their potential utilization in rechargeable magnesium batteries (RMB). The simplest complex cation, namely, solvated MgCl+, was hypothesized and reported as the most important cation in nonaqueous magnesium electrolyte solutions chemistry. However, such ions have never been isolated as the only cationic species in ethereal solutions developed for RMB. In this study, we report on successful isolation of the pure electrolyte MgCl(THF)5+ - PhAlCl3−, and on the electrochemical behavior of it in ethereal solutions. The structure of this compound was proved by single-crystal X-ray diffraction, Raman, and NMR spectroscopies. The novel MgCl(THF)5PhAlCl3/THF electrolyte solutions exhibit reversible Mg deposition/dissolution processes with anodic stability up to 2.7 V. The application of electrochemical cleaning pre …

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Jul 2023 • ACS Applied Nano Materials

Metal Nanoparticle/Photosystem I Protein Hybrids Coupled to Microantenna Afford Biologically and Electronically Controlled Localized Surface Plasmon Resonance: Implications for …

Itai Carmeli, Ibrahim Tanriover, Tirupathi Malavath, Chanoch Carmeli, Moshik Cohen, Yossi Abulafia, Olga Girshevitz, Shachar Richter, Koray Aydin, Zeev Zalevsky

Localized surface plasmon resonance (LSPR) holds great promise for the next generation of fast nanoscale optoelectronic devices, as silicon-based electronic devices approach fundamental speed and scaling limitations. However, in order to fully exploit the potential of plasmonics, devices and material systems capable of actively controlling and manipulating plasmonic response are essential. Here, we demonstrate active control of the electric field distribution of a microantenna by coupling LSPRs to a photosynthetic protein with outstanding optoelectronic properties and a long-range and efficient exciton transfer ability. The hybrid biosolid state active platform is able to tune and modulate the optical activity of a microplasmonic antenna via the interaction of the bioactive material with plasmon oscillations occurring in the antennae. In addition, we demonstrate that the effect of the coupling can be further enhanced …

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Jul 2023 • Optics Express

Split-well resonant-phonon terahertz quantum cascade laser

Shiran Levy, Nathalie Lander Gower, Silvia Piperno, Sadhvikas J Addamane, John L Reno, Asaf Albo

We present a highly diagonal “split-well resonant-phonon” (SWRP) active region design for GaAs/Al_0.3Ga_0.7As terahertz quantum cascade lasers (THz-QCLs). Negative differential resistance is observed at room temperature, which indicates the suppression of thermally activated leakage channels. The overlap between the doped region and the active level states is reduced relative to that of the split-well direct-phonon (SWDP) design. The energy gap between the lower laser level (LLL) and the injector is kept at 36 meV, enabling a fast depopulation of the LLL. Within this work, we investigated the temperature performance and potential of this structure.

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Jul 2023 • Electrochimica Acta

Simplified FTacV model to quantify the electrochemically active site density in PGM-free ORR catalysts

Ariel Friedman, Rifael Z Snitkoff-Sol, Hilah C Honig, Lior Elbaz

The development of platinum group metal-free catalysts is considered the most prominent path for reducing the cost of low-temperature fuel cells (LTFC). Despite the great advancement in the field, its further progress is currently limited by the ability to understand and mitigate the catalysts’ degradation mechanisms, which up to recent years was limited by the lack of activity descriptors. Recent work showed that this could be solved using Fourier-transformed alternating current voltammetry that enables to deconvolute Faradaic currents arising from the redox reaction of the active sites from the capacitive currents, and by that accurately measure the electrochemically active site density of these catalysts in situ fuel cells. However, the analysis of the results can be complex, requiring simulation software for accurate parameter extraction. Herein, a simplified analysis of Fourier-transformed alternating current voltammetry is …

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Jul 2023 • Nonlinear Optics, Th2A. 3, 2023

Nonlinear x-ray optical wave-mixing in silicon

C Ornelas-Skarin, T Bezriadina, M Fuchs, S Ghimire, JB Hastings, NN Hua, L Leroy, Q Nguyen, G de la Peña, D Popova-Gorelova, S Shwartz, M Trigo, T Sato, D Zhu, DA Reis

We present recent measurements of nonlinear x-ray optical mixing in silicon. These measurements demonstrate how x-ray optical mixing can measure details of the atomic-scale nonlinear electron dynamics that are invisible to purely optical techniques.

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Jul 2023 • Fuel

Design of three-dimensional hexagonal petal-like nickel-copper cobaltite//luffa sponge-derived activated carbon electrode materials for high-performance solid-state supercapattery

Sengodan Prabhu, Moorthy Maruthapandi, Arulappan Durairaj, S Arun Kumar, John HT Luong, Rajendran Ramesh, Aharon Gedanken

Three-dimensional porous nanostructured materials are considered superior materials for energy storage applications due to their high storage capability. A nickel copper-cobalt oxide (NCC) composite with a uniform 3-D porous nanostructure (positive electrode materials) and luffa sponge-derived activated carbon (LPAC) with honeycomb-like structure (negative electrode materials) were synthesized by a simple hydrothermal and chemical method. A sample of the nickel-copper cobalt oxide-5 (NCC-5) nanocomposite reached a high specific capacitance of 1048 F/g at the current density of 0.5 A/g. The NCC-5 nanocomposite sample shows a retention capacity of 93 % after 10,000 charge and discharge cycles with 95 % of Coulombic efficiency (CE). The LPAC illustrates a remarkable specific capacitance of 909 F/g at 1 A/g of current density, compared to the best literature value of 400 F/g. The full-cell NCC-5//LPAC …

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Jul 2023 • Optics Express

Split-well resonant-phonon terahertz quantum cascade laser

Shiran Levy, Nathalie Lander Gower, Silvia Piperno, Sadhvikas J Addamane, John L Reno, Asaf Albo

We present a highly diagonal “split-well resonant-phonon” (SWRP) active region design for GaAs/Al_0.3Ga_0.7As terahertz quantum cascade lasers (THz-QCLs). Negative differential resistance is observed at room temperature, which indicates the suppression of thermally activated leakage channels. The overlap between the doped region and the active level states is reduced relative to that of the split-well direct-phonon (SWDP) design. The energy gap between the lower laser level (LLL) and the injector is kept at 36 meV, enabling a fast depopulation of the LLL. Within this work, we investigated the temperature performance and potential of this structure.

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Jun 2023 • Optics Continuum

Remote sensing of human skin temperature by AI speckle pattern analysis

Ofir Ben David, Yevgeny Beiderman, Sergey Agdarov, Yafim Beiderman, Zeev Zalevsky

Analysis of dynamic differential speckle patterns, scattered from human tissues illuminated by a laser beam, has been found by many researchers to be applicable for noncontact sensing of various biomedical parameters. The COVID-19 global pandemic brought the need for massive rapid-remote detection of a fever in closed public spaces. The existing non-contact temperature measurement methods have a significant tradeoff between the measurement distance and accuracy. This paper aims to prove the feasibility of an accurate temperature measurement system based on speckle patterns analysis, enabling the sensing of human temperature from an extended distance greater than allowed by the existing methods. In this study, we used speckle patterns analysis combined with artificial intelligence (AI) methods for human temperature extraction, starting with fever/no fever binary classification and continuing with …

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Jun 2023 • Physical Review B

Free electron laser stochastic spectroscopy revealing silicon bond softening dynamics

Dario De Angelis, Emiliano Principi, Filippo Bencivenga, Daniele Fausti, Laura Foglia, Yishay Klein, Michele Manfredda, Riccardo Mincigrucci, Angela Montanaro, Emanuele Pedersoli, Jacopo Stefano Pelli Cresi, Giovanni Perosa, Kevin C Prince, Elia Razzoli, Sharon Shwartz, Alberto Simoncig, Simone Spampinati, Cristian Svetina, Jakub Szlachetko, Alok Tripathi, Ivan A Vartanyants, Marco Zangrando, Flavio Capotondi

Time-resolved x-ray emission/absorption spectroscopy (Tr-XES/XAS) is an informative experimental tool sensitive to electronic dynamics in materials, widely exploited in diverse research fields. Typically, Tr-XES/XAS requires x-ray pulses with both a narrow bandwidth and subpicosecond pulse duration, a combination that in principle finds its optimum with Fourier transform-limited pulses. In this work, we explore an alternative experimental approach, capable of simultaneously retrieving information about unoccupied (XAS) and occupied (XES) states from the stochastic fluctuations of broadband extreme ultraviolet pulses of a free electron laser. We used this method, in combination with singular-value decomposition and Tikhonov regularization procedures, to determine the XAS/XES response from a crystalline silicon sample at the L 2, 3 edge, with an energy resolution of a few tens of meV. Finally, we combined this …

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Jun 2023 • Electrochimica Acta

Correlation between the electrochemical response and main components structure in solutions for rechargeable Mg batteries based on THF and the reaction products of tBuMgCl and …

Sankalpita Chakrabarty, Yuri Glagovsky, Ananya Maddegalla, Natalia Fridman, Dmitry Bravo-Zhivotovski, Doron Aurbach, Ayan Mukherjee, Malachi Noked

The electrochemical response of ethereal solutions containing magnesium organohaloaluminate complexes has drawn great interest in recent decades owing to their relevance to rechargeable magnesium batteries, as demonstrated with solutions containing complexes formed by reacting R2Mg and AlCl2R moieties in ethers like tetrahydrofuran (THF). However, most of previous reports focused on battery related performances, and less on the structure of the active species. Herein, we focus on (1) identifying electroactive species and (2) correlating the electrochemical properties of their solutions to the preparation modes: either through reactions of their precursors in THF, or by dissolving isolated crystallized products in the ether solvent. Specifically, we explore the products of the reaction of the Grignard reagent t-BuMgCl with AlCl3 (1:1) in THF, and how their presence in solutions affect their electrochemical …

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Jun 2023 • arXiv preprint arXiv:2306.16209

Efficient Reduction of Casimir Forces by Self-assembled Bio-molecular Thin Films

René IP Sedmik, Alexander Urech, Zeev Zalevsky, Itai Carmeli

Casimir forces, related to London-van der Waals forces, arise if the spectrum of electromagnetic fluctuations is restricted by boundaries. There is great interest both from fundamental science and technical applications to control these forces on the nano scale. Scientifically, the Casimir effect being the only known quantum vacuum effect manifesting between macroscopic objects, allows to investigate the poorly known physics of the vacuum. In this work, we experimentally investigate the influence of self-assembled molecular bio and organic thin films on the Casimir force between a plate and a sphere. We find that molecular thin films, despite being a mere few nanometers thick, reduce the Casimir force by up to 14%. To identify the molecular characteristics leading to this reduction, five different bio-molecular films with varying chemical and physical properties were investigated. Spectroscopic data reveal a broad absorption band whose presence can be attributed to the mixing of electronic states of the underlying gold layer and those of the molecular film due to charge rearrangement in the process of self-assembly. Using Lifshitz theory we calculate that the observed change in the Casimir force is consistent with the appearance of the new absorption band due to the formation of molecular layers. The desired Casimir force reduction can be tuned by stacking several monolayers, using a simple self-assembly technique in a solution. The molecules - each a few nanometers long - can penetrate small cavities and holes, and cover any surface with high efficiency. This process seems compatible with current methods in the production of micro …

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Jun 2023 • Journal of Investigative Dermatology

Altered RNA editing in atopic dermatitis highlights the role of double-stranded RNA for immune surveillance

Miriam Karmon, Eli Kopel, Aviv Barzilai, Polina Geva, Eli Eisenberg, Erez Y Levanon, Shoshana Greenberger

Atopic dermatitis (AD) is associated with dysregulated type 1 IFN‒mediated responses, in parallel with the dominant type 2 inflammation. However, the pathophysiology of this dysregulation is largely unknown. Adenosine-to-inosine RNA editing plays a critical role in immune regulation by preventing double-stranded RNA recognition by MDA5 and IFN activation. We studied global adenosine-to-inosine editing in AD to elucidate the role played by altered editing in the pathophysiology of this disease. Analysis of three RNA-sequencing datasets of AD skin samples revealed reduced levels of adenosine-to-inosine RNA editing in AD. This reduction was seen globally throughout Alu repeats as well as in coding genes and in specific pre-mRNA loci expected to create long double-stranded RNA, the main substrate of MDA5 leading to type I IFN activation. Consistently, IFN signature genes were upregulated. In contrast …

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Jun 2023 • ImmunoInformatics

AIRR community curation and standardised representation for immunoglobulin and T cell receptor germline sets

William D Lees, Scott Christley, Ayelet Peres, Justin T Kos, Brian Corrie, Duncan Ralph, Felix Breden, Lindsay G Cowell, Gur Yaari, Martin Corcoran, Gunilla B Karlsson Hedestam, Mats Ohlin, Andrew M Collins, Corey T Watson, Christian E Busse, The AIRR Community

Analysis of an individual's immunoglobulin or T cell receptor gene repertoire can provide important insights into immune function. High-quality analysis of adaptive immune receptor repertoire sequencing data depends upon accurate and relatively complete germline sets, but current sets are known to be incomplete. Established processes for the review and systematic naming of receptor germline genes and alleles require specific evidence and data types, but the discovery landscape is rapidly changing. To exploit the potential of emerging data, and to provide the field with improved state-of-the-art germline sets, an intermediate approach is needed that will allow the rapid publication of consolidated sets derived from these emerging sources. These sets must use a consistent naming scheme and allow refinement and consolidation into genes as new information emerges. Name changes should be minimised, but …

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Jun 2023 • Quantum 2.0, QTh3A. 2, 2023

Nanometric-scale phase contrast imaging with undetected x-ray photons

Haim Aknin, Sharon Shwartz

We show that a system using down conversion of x-ray photons into optical photons together with the concept of quantum imaging with undetected photons can provide nanoscale resolution even for radiation sensitive samples.

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Jun 2023 • Journal of Power Sources

Zn-enriched cathode layer interface via atomic surface reduction of LiNi0. 5Mn1. 5O4: Computational and experimental insights

Shubham Garg, Sarah Taragin, Arka Saha, Olga Brontvein, Kevin Leung, Malachi Noked

Despite having the ability to deliver 650 W h kg−1 in addition to the impressive rate capability, superior thermal stability, and facilitated electronic and ionic lithium conduction, LiNi0.5Mn1.5O4 (LNMO) is far from commercial applications. LNMO suffers from irreversible electrolytic degradation on its surface under high voltage operations leading to capacity fading and poor battery life. Therefore, this work aims to improve the stability and electrochemical behavior of LNMO by creating a Zn-enriched cathode layer interface via eccentric and facile diethyl zinc-assisted atomic surface reduction (Zn-ASR). In-depth surface characterization tools and computational calculations demonstrates a conformal 7-8 nm thin Zn-O and C-O enriched layer encapsulating the cathode particles resulting from Zn-ASR. The intensive comparative electrochemical and spectroscopic analysis, indicates superior electrochemical performance of …

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