BINA

2708 articles

72 publishers

Join mailing list

Aug 2022 • arXiv preprint arXiv:2208.07799v1

Deep subwavelength resonant metaphotonics enabled by high-index topological insulator bismuth telluride

Danveer Singh, Sukanta Nandi, Yafit Fleger, Shnay Cohen Z., Tomer Lewi

In nanophotonics, small mode volumes, high-quality factor (Q) 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 (TI) are a class of insulating materials that host topologically protected surface states, some of which exhibit extraordinary high permittivity values. Here, we study the optical properties of TI bismuth telluride (Bi2Te3) single crystals. We find 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, we demonstrate that Bi2Te3 metasurfaces are capable of squeezing light in deep subwavelength structures, with the fundamental magnetic dipole (MD) resonance confined in unit cell size smaller than {\lambda}/10. We further show that dense ultrathin metasurface arrays can simultaneously provide large magnetic and electric field enhancements arising from the surface metallic states and the high index of the bulk. These findings demonstrate the potential of chalcogenide TI materials as a platform leveraging the unique combination of ultra-high-index dielectric response with surface metallic states for metamaterial design and nanophotonic applications in sensing, non-linear generation, and quantum information.

Show more

Aug 2022 • ACS nano

Noninvasive Nanodiamond Skin Permeation Profiling Using a Phase Analysis Method: Ex Vivo Experiments

Channa Shapira, Daniel Itshak, Hamootal Duadi, Yifat Harel, Ayelet Atkins, Anat Lipovsky, Ronit Lavi, Jean Paul Lellouche, Dror Fixler

Carbon-based nanoparticles (NPs) are widely used in nanotechnology. Among them, nanodiamonds (NDs) are suitable for biotechnology and are especially interesting for skin delivery and topical treatments. However, noninvasive detection of NDs within the different skin layers or analyzing their penetration ability is complicated due to the turbid nature of the tissue. The iterative multiplane optical properties extraction (IMOPE) technique detects differences in the optical properties of the measured item by a phase-image analysis method. The phase image is reconstructed by the multiplane Gerchberg–Saxton algorithm. This technique, traditionally, detects differences in the reduced scattering coefficients. Here, however, due to the actual size of the NDs, the IMOPE technique’s detection relies on absorption analysis rather than relying on scattering events. In this paper, we use the IMOPE technique to detect the …

Show more

Aug 2022 • SPring-8/SACLA Research Report

Higher-Order X-ray-Optical Wave Mixing

Priyanka Chakraborti, Ozgur Culfa, Matthias Fuchs, Johann Haber, David Reis, Sharon Shwartz, Kenji Tamasaku, Samuel Teitelbaum

The goal of the experiment was to investigate higher-order X-ray-optical sum-frequency generation (XSFG) as a means to study the dynamics of linear and nonlinear optically-induced local polarization effects in solids with Angstrom resolution. XSFG can be used as time-resolved atomic-scale probe of the dynamics of optically induced charge densities. The ability to optically control carrier dynamics in samples at the microscopic scale has the potential to become the basis of ultrafast optical switching of currents and future petahertz optoelectronic devices.

Show more

Aug 2022 • arXiv preprint arXiv:2208.10538

Two-Dimensional Tunable Solid-State Random laser in the Visible

Bhupesh Kumar, Ran Homri, Patrick Sebbah

A two-dimensional multimode random laser emitting in the visible frequency range of the optical spectrum is proposed, designed and investigated, in which optical feedback is provided by randomly-distributed air holes embedded in dye-doped polymer film. Dependence of lasing threshold on scatterer density and pump spot size has been investigated. Furthermore, peak of the gain curve shows systematic spectral blue shift with increasing scatterer density, as well as pump spot size. Such a 2D random laser provides with a compact on-chip tunable laser source and a unique platform to explore non-Hermitian photonics in the visible

Show more

Aug 2022 • Proceedings of the National Academy of Sciences

The Role of Spin-Flip Collisions in a Dark-Exciton Condensate

Subhradeep Misra, Michael Stern, Vladimir Umansky, Israel Bar-Joseph

We show that a Bose–Einstein condensate consisting of dark excitons forms in GaAs coupled quantum wells at low temperatures. We find that the condensate extends over hundreds of micrometers, well beyond the optical excitation region, and is limited only by the boundaries of the mesa. We show that the condensate density is determined by spin-flipping collisions among the excitons, which convert dark excitons into bright ones. The suppression of this process at low temperature yields a density buildup, manifested as a temperature-dependent blueshift of the exciton emission line. Measurements under an in-plane magnetic field allow us to preferentially modify the bright exciton density and determine their role in the system dynamics. We find that their interaction with the condensate leads to its depletion. We present a simple rate-equations model, which well reproduces the observed temperature, power, and …

Show more

Aug 2022 • Optical Fiber Sensors, Th4. 67, 2022

Forward Brillouin Point Sensor in a Multi-Core Fiber

Keren Shemer, Gil Bashan, Elad Zehavi, Hilel Hagai Diamandi, Alon Bernstein, Kavita Sharma, Yosef London, David Barrera, Salvador Sales, Avi Zadok

Forward Brillouin point sensing is demonstrated in a multi-core fiber. Acoustic waves are stimulated by light in one core and monitored using a grating in another. Measurements distinguish between ethanol and water outside the cladding.

Show more

Aug 2022 • Surgical Endoscopy

S194–Imaging through scattering media by 3D spatial filtering embedded into micro-endoscope

Zeev Zalevsky, Shimon Elkabetz, Arkady Rudnitsky, Oran Herman, Amihai Meiri, Asaf Shahmoon

BackgroundThe main objective is related to the capability of integrating into minimally invasive and ultra-thin disposable micro-endoscopic tool, a modality of realizing high-resolution imaging through scattering medium such as blood while performing medical procedure. In this research we aim for the first time to present a time-multiplexing super-resolving approach exhibiting enhanced focus sensitivity, generated by 3D spatial filtering, for significant contrast increase in images collected through scattering medium.MethodOur innovative method of imaging through scattering media provides imaging of only one specific object plane in scattering medium’s volume while suppressing the noise coming from all other planes. The method should be assisted with axial scanning to perform imaging of the entire 3D object’s volume. In our developed optical system noise suppression is achieved by 3D spatial filtering …

Show more

Aug 2022 • arXiv preprint arXiv:2208.10262

Controls that expedite scale-invariant transport in disordered systems

Marc Höll, Alon Nissan, Brian Berkowitz, Eli Barkai

Transport in disordered media, such as those involving charge carriers in amorphous semiconductors, or contaminants in hydrogeological systems, are often described by time scale-free processes. We study the statistical properties of the first passage time of biased processes in different models, and employ the big jump principle that shows the dominance of the maximum trapping time on the first passage time. Inspired by the restart paradigm, we demonstrate that the removal of this maximum significantly expedites transport. As the disorder increases, the system enters a phase where the removal shows a dramatic effect. Our results show how we may speed up transport in strongly disordered systems exploiting scale invariance.

Show more

Aug 2022 • Nanomedicine: Nanotechnology, Biology and Medicine

Multifunctional nanoprobe for real-time in vivo monitoring of T cell activation

Oshra Betzer, Yue Gao, Astar Shamul, Menachem Motiei, Tamar Sadan, Ronen Yehuda, Ayelet Atkins, Cyrille J Cohen, Mingwu Shen, Xiangyang Shi, Rachela Popovtzer

Genetically engineered T cells are a powerful new modality for cancer immunotherapy. However, their clinical application for solid tumors is challenging, and crucial knowledge on cell functionality in vivo is lacking. Here, we fabricated a nanoprobe composed of dendrimers incorporating a calcium sensor and gold nanoparticles, for dual-modal monitoring of engineered T cells within a solid tumor. T cells engineered to express a melanoma-specific T-cell receptor and loaded with the nanoprobe were longitudinally monitored within melanoma xenografts in mice. Fluorescent imaging of the nanoprobe's calcium sensor revealed increased intra-tumoral activation of the T cells over time, up to 24 h. Computed tomography imaging of the nanoprobe's gold nanoparticles revealed the cells' intra-tumoral distribution pattern. Quantitative analysis revealed the intra-tumoral T cell quantities. Thus, this nanoprobe reveals intra …

Show more

Aug 2022 • ACS Applied Energy Materials

High-Energy Ni-Rich LiNi0.85Co0.1Mn0.05O2 Cathode Material for Li-Ion Batteries Enhanced by Nd- and Y-Doping. A Structural, Electrochemical, and Thermal …

Yehonatan Levartovsky, Arup Chakraborty, Sooraj Kunnikuruvan, Sandipan Maiti, Judith Grinblat, Michael Talianker, Doron Aurbach, Dan Thomas Major

Ni-rich LiNi1–x–yCoxMnyO2 (1 – x – y > 0.5) (NCMs) cathode materials have shown great promise in energy-intensive applications, such as electric vehicles. However, as many layered cathodes do, they suffer from structural and electrochemical degradation during cycling. In this study, we show that Nd- and Y-doped materials, Li(Ni0.85Co0.1Mn0.05)0.995Nd0.005O2 and Li(Ni0.85Co0.1Mn0.05)0.995Y0.005O2, have significantly better structural, electrochemical, and thermal properties compared to the reference LiNi0.85Co0.1Mn0.05O2 (NCM85) due to enhanced structural stability. The doped electrodes were found to have significantly higher specific discharge capacities, better capacity retention, and lower voltage hysteresis compared to the reference (undoped) electrodes. SEM images of the focused-ion beam (FIB) cut of the particles of the doped material showed that they have less cracks when compared …

Show more

Aug 2022 • Available at SSRN 3737807

Decomposition of Individual SNP Patterns from Mixed DNA Samples

Gabriel Azhari, Shamam Waldman, Netanel Ofer, Yosi Keller, Shai Carmi, Gur Yaari

Single Nucleotide Polymorphism markers (SNPs) have great potential to identify individuals, family relations, biogeographical ancestry, and phenotypic traits. In many forensic situations DNA mixtures of a victim and an unknown suspect exist. Extracting from such samples the suspect's SNP profile can be used to assist investigation and gather intelligence. Computational tools to determine inclusion/exclusion of a known individual from a mixture exist, but no algorithm to extract an unknown SNP profile without a list of suspects is available. We present here AH-HA, a novel computational approach for extracting an unknown SNP profile from a whole genome sequencing (WGS) of a two person mixture. It utilizes techniques similar to the ones used in haplotype phasing. It constructs the inferred genotype as an imperfect mosaic of haplotypes from a reference panel of the target population. It is shown to outperform more simplistic approaches, maintaining high performance through a wide range of sequencing depths (500x-5x). AH-HA can be applied in cases of victim-suspect mixtures and improve the capabilities of the investigating forces. This approach can be extended to more complex mixtures, with more donors and less prior information, further motivating the development of SNP based forensics technologies.

Show more

Aug 2022 • arXiv preprint arXiv:2108.13047

Measurement-induced quantum walks

A Didi, E Barkai

We investigate a tight binding quantum walk on a graph. Repeated stroboscopic measurements of the position of the particle yield a measured "trajectory", and a combination of classical and quantum mechanical properties for the walk are observed. We explore the effects of the measurements on the spreading of the packet on a one dimensional line, showing that except for the Zeno limit, the system converges to Gaussian statistics similarly to a classical random walk. A large deviation analysis and an Edgeworth expansion yield quantum corrections to this normal behavior. We then explore the first passage time to a target state using a generating function method, yielding properties like the quantization of the mean first return time. In particular, we study the effects of certain sampling rates which cause remarkable change in the behavior in the system, like divergence of the mean detection time in finite systems and a decomposition of the phase space into mutually exclusive regions, an effect that mimics ergodicity breaking, whose origin here is the destructive interference in quantum mechanics. For a quantum walk on a line we show that in our system the first detection probability decays classically like , this is dramatically different compared to local measurements which yield a decay rate of , indicating that the exponents of the first passage time depends on the type of measurements used.

Show more

Aug 2022 • IEEE Photonics Journal

Measurement of the Second-Order Polarizability of Silver Nanoparticles With Reference-Free Hyper-Rayleigh Scattering for Entangled Photon Pair Interaction

Ariel Ashkenazy, Racheli Ron, Tchiya Zar, Hannah Aharon, Adi Salomon, Dror Fixler, Eliahu Cohen

Two-photon interactions of entangled-photon pairs with metallic nanoparticles (NPs) can be enhanced by localized surface-plasmon resonance. Recently, we have described how the properties of this quantum light-matter interaction can be deduced from classical second-harmonic generation measurements performed using a reference-free hyper-Rayleigh scattering method. Herein, we report the results of such classical-light characterization measurements. We obtain a large hyperpolarizability for the NPs, present the dependence of the hyperpolarizability on the NPs' spectral features, and show a dipolar emission pattern for the second-harmonic signal. Our results can be used to optimize entangled-photon pair interactions with metallic NPs to enable first ever detection of this process. Moreover, these results suggest that NPs may be used as source for ultra-broadband entangled-photon pairs through nonphase …

Show more

Aug 2022 • Physical Review B

Nonadiabatically driven open quantum systems under out-of-equilibrium conditions: Effect of electron-phonon interaction

Jakob Bätge, Amikam Levy, Wenjie Dou, Michael Thoss

In this paper we explore the effects of nonadiabatic external driving on the dynamics of an electronic system coupled to two electronic leads and to a phonon mode, with and without damping. In the limit of slow driving, we establish nonadiabatic corrections to thermodynamic and transport quantities. In particular, we study the first-order correction to the work done by the driving, the charge current, and the vibrational excitation using a perturbative expansion. We then compare the results to the numerically exact hierarchical equations of motion (HEOM) approach. Furthermore, the HEOM analysis spans both the weak and strong system-bath coupling regime and the slow-and fast-driving limits. We show that the electronic friction and the nonadiabatic corrections to the charge current provide a clear indicator for the Franck-Condon effect and for nonresonant tunneling processes. We also discuss the validity of the …

Show more

Aug 2022 • Optical Fiber Sensors, Tu1. 4, 2022

Brillouin Optical Time-Domain Distributed Analysis of Cladding Modes in a Coated Fiber

Elad Zehavi, Alon Bernstein, Gil Bashan, Yosef London, Hilel Hagai Diamandi, Kavita Sharma, Mirit Hen, A Zadok

Brillouin optical time domain analysis of coupling to cladding modes of standard, coated fiber is demonstrated. Uncertainty in local changes of effective indices is below 10-6 RIU. Local effect of acetone on coating is identified.

Show more

Aug 2022 • ACS Applied Nano Materials

Dealloyed Octahedral PtCu Nanoparticles as High-Efficiency Electrocatalysts for the Oxygen Reduction Reaction

Melina Zysler, Enrique Carbo-Argibay, Paulo J Ferreira, David Zitoun

Pt-based nanoparticles (NPs) are used as electrocatalysts for the oxygen reduction reaction (ORR) that occurs at the cathode of a proton exchange membrane fuel cell, because of their high efficiency. Among these NPs, PtCu electrocatalysts are an important subclass, in which composition, morphology, size, crystal structure, and atomic distribution are tuned to optimize the performance and durability of the catalyst. Most of the efforts so far in the field have been dedicated toward increasing the catalytic activity and stability of these NPs, while reducing the amount of precious material. In this paper, we present a solvothermal method used for the synthesis of carbon-supported octahedral PtCu NPs that show high efficiency toward the ORR. In particular, a specific activity of 1.02 mA cm–2 was achieved after 10,000 cycles (accelerated degradation test) in which 84% of the electrochemical surface area was maintained …

Show more

Aug 2022

Characterizing nanometric thin films with far-field light

Omer Shavit, Carine Julien, Ilya Olevsko, Mohamed Hamode, Yossi Abulafia, Hervé Suaudeau, Vincent Armand, Martin Oheim, Adi Salomon

Ultra-thin, transparent films are being used as protective layers on semiconductors, solar cells, as well as for nano-composite materials and optical coatings. Nano-sensors, photonic devices and calibration tools for axial super-resolution microscopies, all rely on the controlled fabrication and analysis of ultra-thin layers. Here, we describe a simple, non-invasive, optical technique for simultaneously characterizing the refractive index, thickness, and homogeneity of nanometric transparent films. In our case, these layers are made of the biomimetic polymer, My-133-MC, having a refractive index of 1.33, so as to approach the cytosol for biological applications. Our technique is based on the detection in the far field and the analysis of supercritical angle fluorescence (SAF), i.e., near-field emission from molecular dipoles located very close to the dielectric interface. SAF emanates from a 5-nm J-aggregate emitter layer deposited on and in contact with the inspected polymer film. Our results compare favorably to that obtained through a combination of atomic force and electron microscopy, surface-plasmon resonance spectroscopy and ellipsometry. We illustrate the value of the approach in two applications, (i), the measurement of axial fluorophore distance in a total internal reflection fluorescence geometry; and, (ii), axial super-resolution imaging of organelle dynamics in a living biological sample, cortical astrocytes, an important type of brain cell. In the later case, our approach removes uncertainties in the interpretation of the nanometric axial dynamics of fluorescently labeled vesicles. Our technique is cheap, versatile and it has obvious applications in …

Show more

Aug 2022 • IEEE Photonics Journal

Measurement of the Second-Order Polarizability of Silver Nanoparticles With Reference-Free Hyper-Rayleigh Scattering for Entangled Photon Pair Interaction

Ariel Ashkenazy, Racheli Ron, Tchiya Zar, Hannah Aharon, Adi Salomon, Dror Fixler, Eliahu Cohen

Two-photon interactions of entangled-photon pairs with metallic nanoparticles (NPs) can be enhanced by localized surface-plasmon resonance. Recently, we have described how the properties of this quantum light-matter interaction can be deduced from classical second-harmonic generation measurements performed using a reference-free hyper-Rayleigh scattering method. Herein, we report the results of such classical-light characterization measurements. We obtain a large hyperpolarizability for the NPs, present the dependence of the hyperpolarizability on the NPs' spectral features, and show a dipolar emission pattern for the second-harmonic signal. Our results can be used to optimize entangled-photon pair interactions with metallic NPs to enable first ever detection of this process. Moreover, these results suggest that NPs may be used as source for ultra-broadband entangled-photon pairs through nonphase …

Show more

Aug 2022 • Scientific Reports 12 (1), 1-9, 2022

Remote photonic detection of human senses using secondary speckle patterns

Zeev Kalyuzhner, Sergey Agdarov, Itai Orr, Yafim Beiderman, Aviya Bennett, Zeev Zalevsky

Neural activity research has recently gained signi cant attention due to its association with sensory information and behavior control. However, current methods of brain activity sensing require expensive equipment and physical contact with the subject.We propose a novel photonic-based method for remote detection of human senses. Physiological processes associated with hemodynamic activity due to activation of the cerebral cortex affected by different senses have been detected by remote monitoring of nano‐vibrations generated due to the transient blood ow to speci c regions of the brain. We have found that combination of defocused, self‐interference random speckle patterns with a spatiotemporal analysis using Deep Neural Network (DNN) allows associating between the activated sense and the seemingly random speckle patterns.

Show more

Aug 2022 • Proceedings of the National Academy of Sciences

The Role of Spin-Flip Collisions in a Dark-Exciton Condensate

Subhradeep Misra, Michael Stern, Vladimir Umansky, Israel Bar-Joseph

We show that a Bose–Einstein condensate consisting of dark excitons forms in GaAs coupled quantum wells at low temperatures. We find that the condensate extends over hundreds of micrometers, well beyond the optical excitation region, and is limited only by the boundaries of the mesa. We show that the condensate density is determined by spin-flipping collisions among the excitons, which convert dark excitons into bright ones. The suppression of this process at low temperature yields a density buildup, manifested as a temperature-dependent blueshift of the exciton emission line. Measurements under an in-plane magnetic field allow us to preferentially modify the bright exciton density and determine their role in the system dynamics. We find that their interaction with the condensate leads to its depletion. We present a simple rate-equations model, which well reproduces the observed temperature, power, and …

Show more

Aug 2022 • Neuro-oncology Advances

BSCI-05 REPURPOSING PROPOFOL FOR THE TREATMENT OF BRAIN METASTASES

Donald Penning, Simona Cazacu, Raphael Nizar, Hodaya Goldstein, Gila Kazimirsky, Stephen Brown, Lisa Rogers, Chaya Brodie

BACKGROUNDRecent clinical studies suggest beneficial effects of propofol anesthesia on tumor progression and patient survival in solid tumors but reported benefits are modest. One potential reason is the relatively short, single exposure to propofol, limited to the surgical period. Brain metastases (BM) are the most common brain tumors in adults. Metastatic tumors develop following infiltration of the brain from primary tumors such as lung, breast, melanoma, and colorectal cancers. BM are treated with combination therapies, including surgery, radiotherapy, chemotherapy, and immunotherapy, however the prognosis of most patients with BM remains dismal. In this report we investigated the effects of propofol plus radiation on cancer stem cells derived from human lung cancer brain metastases (BM-CSCs) and their cross-talk with microglia.OBJECTIVESOur hypothesis is that propofol can be repurposed as a …

Show more

logo
Articali

Powered by Articali

TermsPrivacy