TAU Nanocenter

Strong coupling in light-matter systems is a central concept in cavity quantum electrodynamics and is essential for many quantum technologies. Especially in the optical range, full control of highly connected multi-qubit systems necessitates quantum coherent probes with nanometric spatial resolution, which are currently inaccessible. Here, we propose the use of free electrons as high-resolution quantum sensors for strongly coupled light-matter systems. Shaping the free-electron wave packet enables the measurement of the quantum state of the entire hybrid systems. We specifically show how quantum interference of the free-electron wave packet gives rise to a quantum-enhanced sensing protocol for the position and dipole orientation of a subnanometer emitter inside a cavity. Our results showcase the great versatility and applicability of quantum interactions between free electrons and strongly coupled cavities …

In 1952 David Bohm proposed an interpretation of quantum mechanics, in which the evolution of states results from trajectories governed by classical equations of motion but with an additional potential determined by the wave function. There exist only a few experiments that test this concept and they employed weak measurement of non-classical light. In contrast, we reconstruct the Bohm trajectories in a classical hydrodynamic system of surface gravity water waves, by a direct measurement of the wave packet. Our system is governed by a wave equation that is analogous to the Schr ̈odinger equation which enables us to transfer the Bohm formalism to classical waves. In contrast to a quantum system, we can measure simultaneously their amplitude and phase. In our experiments, we employ three characteristic types of surface gravity water wave packets: two and three Gaussian temporal slits and temporal Airy …

We report on the experimental realization and a systematic study of optical frequency comb generation in doubly resonant intracavity second harmonic generation (SHG). The efficiency of intracavity nonlinear processes usually benefits from the increasing number of resonating fields. Yet, achieving the simultaneous resonance of different fields may be technically complicated, all the more when a phase matching condition must be fulfilled as well. In our cavity we can separately control the resonance condition for the fundamental and its second harmonic, by simultaneously acting on an intracavity dispersive element and on a piezo-mounted cavity mirror, without affecting the quasi-phase matching condition. In addition, by finely adjusting the laser-to-cavity detuning, we are able to observe steady comb emission across the whole resonance profile, revealing the multiplicity of comb structures, and the substantial role of thermal effects on their dynamics. Lastly, we report the results of numerical simulations of comb dynamics, which include photothermal effects, finding a good agreement with the experimental observations. Our system provides a framework for exploring the richness of comb dynamics in doubly resonant SHG systems, assisting the design of chip-scale quadratic comb generators.

Dielectric laser accelerators (DLAs) are fundamentally based on the interaction of photons with free electrons, where energy and momentum conservation are satisfied by mediation of a nanostructure. In this scheme, the photonic nanostructure induces near-fields which transfer energy from the photon to the electron, similar to the inverse-Smith–Purcell effect described in metallic gratings. This, in turn, may provide ground-breaking applications, as it is a technology promising to miniaturize particle accelerators down to the chip scale. This fundamental interaction can also be used to study and demonstrate quantum photon-electron phenomena. The spontaneous and stimulated Smith–Purcell effect and the photon-induced near-field electron-microscopy (PINEM) effect have evolved to be a fruitful ground for observing quantum effects. In particular, the energy spectrum of the free electron has been shown to have discrete energy peaks, spaced with the interacting photon energy. This energy spectrum is correlated to the photon statistics and number of photon exchanges that took place during the interaction. We give an overview of DLA and PINEM physics with a focus on electron phase-space manipulation.

Controlled release systems are often integrated into polymeric scaffolds to supply essential biofactors to trigger physiological processes in engineered tissues. Here, we report the modification of chondroitin sulfate (CS) electroactive polymer with gold nanorods (AuNRs) to create hybrid macroporous scaffolds for enhanced on-demand release of growth factors and cytokines. The mechanical properties, porosity and degradation of the hybrid scaffolds were evaluated, and the viability and functionality of seeded cardiac cells were assessed. Following, the ability to control the release of the enzyme lysozyme, and the cytokine, stromal cell-derived factor 1 (SDF-1) by applying electrical stimulation, was demonstrated. The AuNRs were able to increase the current through the scaffolds, providing an efficient on–off release profile of SDF-1, which resulted in higher migration of cells expressing CXCR4 receptor. Finally, the …

Molybdenum disulfide (MoS2) has recently emerged as one of the most promising water nano-based adsorbent materials for heavy metal removal with the potential to provide an alternative to conventional water decontamination technologies. In this study, we demonstrate the trade-off between mercuric removal capacity and overall MoS2 adsorbent stability, both driven by MoS2 synthesis parameters. A bottom-up hydrothermal synthesis setup at various growth temperatures was employed to grow flower-like MoS2 films onto planar alumina supports. A thorough material characterization suggests that an increase in growth temperature from 150 to 210 °C results in higher MoS2 crystallinity. Interestingly, elevated growth temperatures resulted in poor mercuric removal (525 mg g–1, K = 2.2 × 10–3 h–1), yet showed enhanced chemical stability (i.e., minimal molybdenum leaching during exposure to mercury). On the …

This study provides an analysis of the current state of microplastic (MP) contamination along the Mediterranean coastline of Israel. Six strategic sites were monitored in this study – each representing a unique coastal environment. We conclude that Tel Aviv and Hadera, both located near stream estuaries, were highly contaminated (18,777 particles/m3) with MP compared to the other locations. The MP detected included both secondary MP and pristine polymeric pellets. In-depth characterization of the MP illustrated a large percentage of both fragmented and film MP morphologies and the most common MP polymers were polyethylene and polypropylene. Further particle analysis showed that MPs were contaminated with biofilm, including microorganisms such as diatoms, as well as metal residues. Through the spatial analysis presented herein we suggest that local rivers are significant contributors to MP …

This study provides an analysis of the current state of microplastic (MP) contamination along the Mediterranean coastline of Israel. Six strategic sites were monitored in this study – each representing a unique coastal environment. We conclude that Tel Aviv and Hadera, both located near stream estuaries, were highly contaminated (18,777 particles/m3) with MP compared to the other locations. The MP detected included both secondary MP and pristine polymeric pellets. In-depth characterization of the MP illustrated a large percentage of both fragmented and film MP morphologies and the most common MP polymers were polyethylene and polypropylene. Further particle analysis showed that MPs were contaminated with biofilm, including microorganisms such as diatoms, as well as metal residues. Through the spatial analysis presented herein we suggest that local rivers are significant contributors to MP …

Celebrating its centennial anniversary, the Stern–Gerlach experiment has proven to be one of the cornerstones of quantum mechanics, unravelling the quantized nature of the spin angular momentum, and being used in various applications ranging from matter-wave interferometry to weak measurements. Here we report an analogous all-optical Stern–Gerlach experiment in nonlinear optics, where the frequency of light acts as a pseudospin. We observe the splitting of light into two beams, each comprising a frequency-bin superposition, in the presence of a nonlinear coupling gradient. We further realize the phase-sensitive deflection of a distinct frequency-bin superposition into a single direction. Our work constitutes a frequency-domain all-optical coherent deflection of light, offering large bandwidths, fast switching rates and tunability, which are valuable for both classical and quantum information. Furthermore, our …

Transverse second-harmonic generation, in which the emission angles of the second harmonic are determined by the spatial modulation of the quadratic nonlinearity, has important applications in nonlinear optical imaging, holography, and beam shaping. Here we study the role of the local duty cycle of the nonlinearity on the light intensity distribution in transverse second-harmonic generation, taking the generation of perfect vortices in periodically poled ferroelectric crystal as an example. We show, theoretically and experimentally, that spatial variations of the nonlinearity modulation must be accompanied by the corresponding changes of the width of inverted ferroelectric domains, to ensure uniformity of the light intensity distribution in the generated second harmonic. This work provides a fundamental way to achieve high-quality transverse second-harmonic generation and, hence, opens more possibilities in applications based on harmonic generation and its control.

Nanotechnology has shown great potential to increase global food production and enhance food security. However, large-scale application of nano-enabled plant agriculture necessitates careful adjustments in design to overcome barriers associated with targeted nanomaterial delivery and their safety concerns. The research herein proposes the delivery of Copper from immobilized and non-immobilized copper oxide nanoparticles (Cu2O), an active nanomaterial with antifungal and micro-nutrient properties. A benign and biodegradable jellyfish-based hydrogel was used as a platform during Cu2O delivery to soils. The delivery kinetics and Cu dissolution from the nanocomposite were compared to those obtained with crosslinked ionic copper in hydrogel, which was found to be a less controlled composite. In addition, changing environmental conditions from DI to soil extracts resulted in a decrease in the Cu …

Recent increasing industrial demand for precious metals suggests recycling and regeneration as a means to decrease the energy consumption and cost associated with precious metal use. Molybdenum disulfide (MoS2) nanosheets have demonstrated selective and efficient adsorption potential toward heavy metals, but their application in recovering precious metals has not been reported. In this study, we affix MoS2 onto platforms to increase the sustainability and practicality of silver (used as a precious metal model) recovery from wastes, with the optimal design determined by effectiveness, sustainability, and scalability criteria. MoS2 was synthesized on three robust platforms─sand particles, alumina beads, and PTFE beads─using bottom-up solvothermal methods. While a stable homogeneous molybdenum sulfides and oxides layer was formed over sand and alumina, PTFE beads were only partially coated …

Celebrating its centennial anniversary, the Stern–Gerlach experiment has proven to be one of the cornerstones of quantum mechanics, unravelling the quantized nature of the spin angular momentum, and being used in various applications ranging from matter-wave interferometry to weak measurements. Here we report an analogous all-optical Stern–Gerlach experiment in nonlinear optics, where the frequency of light acts as a pseudospin. We observe the splitting of light into two beams, each comprising a frequency-bin superposition, in the presence of a nonlinear coupling gradient. We further realize the phase-sensitive deflection of a distinct frequency-bin superposition into a single direction. Our work constitutes a frequency-domain all-optical coherent deflection of light, offering large bandwidths, fast switching rates and tunability, which are valuable for both classical and quantum information. Furthermore, our …

Metasurfaces constitute a powerful approach to generate and control light by engineering optical material properties at the subwavelength scale. Recently, this concept was applied to manipulate free-electron radiation phenomena, rendering versatile light sources with unique functionalities. In this Letter, we experimentally demonstrate spectral and angular control over coherent light emission by metasurfaces that interact with free-electrons under grazing incidence. Specifically, we study metalenses based on chirped metagratings that simultaneously emit and shape Smith–Purcell radiation in the visible and near-infrared spectral regime. In good agreement with theory, we observe the far-field signatures of strongly convergent and divergent cylindrical radiation wavefronts using in situ hyperspectral angle-resolved light detection in a scanning electron microscope. Furthermore, we theoretically explore simultaneous …

Metasurfaces constitute a powerful approach to generate and control light by engineering optical material properties at the subwavelength scale. Recently, this concept was applied to manipulate free-electron radiation phenomena, rendering versatile light sources with unique functionalities. In this Letter, we experimentally demonstrate spectral and angular control over coherent light emission by metasurfaces that interact with free-electrons under grazing incidence. Specifically, we study metalenses based on chirped metagratings that simultaneously emit and shape Smith–Purcell radiation in the visible and near-infrared spectral regime. In good agreement with theory, we observe the far-field signatures of strongly convergent and divergent cylindrical radiation wavefronts using in situ hyperspectral angle-resolved light detection in a scanning electron microscope. Furthermore, we theoretically explore simultaneous …

Recent increasing industrial demand for precious metals suggests recycling and regeneration as a means to decrease the energy consumption and cost associated with precious metal use. Molybdenum disulfide (MoS2) nanosheets have demonstrated selective and efficient adsorption potential toward heavy metals, but their application in recovering precious metals has not been reported. In this study, we affix MoS2 onto platforms to increase the sustainability and practicality of silver (used as a precious metal model) recovery from wastes, with the optimal design determined by effectiveness, sustainability, and scalability criteria. MoS2 was synthesized on three robust platforms─sand particles, alumina beads, and PTFE beads─using bottom-up solvothermal methods. While a stable homogeneous molybdenum sulfides and oxides layer was formed over sand and alumina, PTFE beads were only partially coated …

We experimentally shape the quantum correlations of spatially entangled photon pairs in a two-dimensionally patterned KTiOPO 4 crystal using nonlinear holography. Our method enables multi-dimensional engineering of quantum states directly using patterned nonlinear photonic crystals.

We design, fabricate, and characterize integrated mode sorters for multimode fibers that guide well-separated vortex modes. We use 3D direct laser printing to print a collimator and a Cartesian to a log-polar mode transformer on the tip of the fiber. This polarization insensitive device can send different modes into different exit angles and is therefore useful for space division multiplexed optical communication. Two types of fibers with two corresponding sorters are used, enabling the sorting of either four or eight different modes in a compact and robust manner. The integration of the vortex fiber and multiplexer opens the door for widespread exploitation of orbital angular momentum (OAM) for data multiplexing in fiber networks.

Optical N00N states are N-photon path entangled states with important applications in quantum metrology. However, their use was limited till now owing to the difficulties of generating them in an efficient and robust manner. Here we propose and experimentally demonstrate two new simple, compact and robust schemes to generate path entangled N00N states with N = 2 that emerge directly from the nonlinear interaction. The first scheme is based on shaping the pump beam, and the second scheme is based on modulating the nonlinear coefficient of the crystal. These new methods exhibit high coincidence count rates for the detection of a N00N state, reaching record value of 2 × 10^5 coincidences per second. We observe super-resolution by measuring the second order correlation on the generated N = 2 state in an interferometric setup, showing the distinct fringe periodicity at half of the optical wavelength. Our findings may pave the way towards scalable and efficient sources for super-resolved quantum metrology applications and for the generation of bright squeezed vacuum states.

Spontaneous parametric downconversion (SPDC) in quantum optics is an invaluable resource for the realization of high-dimensional qudits with spatial modes of light. One of the main open challenges is how to directly generate a desirable qudit state in the SPDC process. This problem can be addressed through advanced computational learning methods; however, due to difficulties in modeling the SPDC process by a fully differentiable algorithm, progress has been limited. Here, we overcome these limitations and introduce a physically constrained and differentiable model, validated against experimental results for shaped pump beams and structured crystals, capable of learning the relevant interaction parameters in the process. We avoid any restrictions induced by the stochastic nature of our physical model and integrate the dynamic equations governing the evolution under the SPDC Hamiltonian. We solve the inverse problem of designing a nonlinear quantum optical system that achieves the desired quantum state of downconverted photon pairs. The desired states are defined using either the second-order correlations between different spatial modes or by specifying the required density matrix. By learning nonlinear photonic crystal structures as well as different pump shapes, we successfully show how to generate maximally entangled states. Furthermore, we simulate all-optical coherent control over the generated quantum state by actively changing the profile of the pump beam. Our work can be useful for applications such as novel designs of high-dimensional quantum key distribution and quantum information processing protocols. In …