Alina Karabchevsky

• Professor
• Full professor at Ben-Gurion University of the Negev

Reservoir computing (RC) is an innovative paradigm in neuromorphic computing that leverages fixed, randomized, internal connections to address the challenge of overfitting. RC has shown remarkable effectiveness in signal processing and pattern recognition tasks, making it well-suited for hardware implementations across various physical substrates,...

The development of straightforward and effective methods to determine the topological charge of phase singular beams is crucial for broadening the applications of optical vortices. Here, a straightforward and elegant method for determining the topological charge of an optical vortex using an innovative switchable achromatic nematic liquid crystal F...

The adsorption of hexane and N-methylaniline was investigated by on-chip vibrational spectroscopy. The interaction with the Pd surface significantly perturbs the vibrational modes of hexane. Near-infrared absorption spectroscopy on the waveguide detected a redshifted C-H stretching vibration. We showed that while rapid evaporation of one component...

A rational design and fabrication approach is proposed for suspended multicore fibers, resulting in the creation of dual‐core and triple‐core suspended fibers with different diameters and one‐side cladding. These fibers are tailored for near‐infrared spectroscopy applications. The multicore‐suspended fibers offer an amplified electromagnetic field...

Solar energy is a source of renewable energy that is harnessed using a range of technologies. With the development of humanity's interest in solar energy, there is a need to collect and store it. However, the current photovoltaic cells that are used to collect solar energy are far from being optimized, and their further development is in much deman...

Integrated photonics is a remarkable platform for scalable classical and quantum light-based information processing. However, polarization manipulation on a chip despite of its fundamental significance in information processing remains elusive. Polarization manipulation capabilities have been recently demonstrated in femtosecond laser-inscribed twi...

Since its creation, the reduction in size of the spectroscope has resulted in a balance between resolution, bandwidth, and signal-to-noise ratio. Up until now, downsized demonstrations have struggled to surmount the technical hurdles of achieving both extremely high resolution (reaching the scale of picometers) and wide bandwidth (exceeding 100 nan...

Possessing intriguing optoelectronic properties, metal halide perovskites can serve as a large-scale platform for miniaturized photonic circuits with on-chip active devices such as lasers and detectors.

Experimental limitations such as design complexity and low optical throughput have prevented photonic nanojet (PNJ) and photonic hook (PH) measurements from demonstrating and characterizing the implementation of narrow intense electromagnetic beams generated from dielectric microelements with circular symmetry. Near-fields optical microscopy can mi...

2D metal carbides and nitrides (MXene) are promising materials platform for on‐chip neural networks owning to their nonlinear saturable absorption effect. The localized surface plasmon resonances in metallic MXene nanoflakes may play an important role in enhancing the electromagnetic absorption; however, their contribution has not been determined d...

Integrated photonics is a remarkable platform for the realization of quantum computations due to its flexibility and scalability. Here we propose a novel paradigm exploiting twisted waveguides as a building block for polarization-encoded quantum photonic computations on a chip. We unveil a transformation (gate) matrix in the closed form and demonst...

Conventional fabrication methods to produce graphene are cumbersome, expensive, and not ecologically friendly. This is due to the fact that the processing of a large volume of raw materials requires large amounts of acids and alkalis which, in turn, require special disposal. Therefore, it is necessary to develop new technologies or to refine existi...

Exceptional points (EPs) of both eigenvalue and eigenvector degeneracy offer remarkable properties of the non-Hermitian systems based on the Jordanian form of Hamiltonians at EPs. Here we propose the perturbation theory able to underpin the physics in the vicinity of the higher-order EPs. The perturbation theory unveils lifting of degeneracy and or...

We report the generation of spatial rogue waves in an actively Q-switched Nd:YAG laser. We observed that spatial rogue waves can emerge when the laser operates in a low-power regime below the self-focusing limit, while the lasing takes place at a large number of high-order transverse modes. These results suggest that the main mechanism leading to r...

In this perspective, we report an opinion on overtone spectroscopy for sensing and discuss the nature of the opportunities perceived for specialists. New spectroscopic strategies can potentially be extended to detect other common toxic byproducts in a chip-scale label-free manner and to enhance the functionality of chemical and biological monitorin...

Optical microfibers find new applications in various fields of industry, which in turn require wear resistance, environmental friendliness and ease of use. However, optical microfibers are fragile. Here we report a new method to prolong the microfiber lifetime by modifying its surface with green-extracted graphene overlayers. Graphene films were ob...

Photonics integrated circuitry would benefit considerably from the ability to arbitrarily control waveguide cross-sections with high precision and low loss, in order to provide more degrees of freedom in manipulating propagating light. Here, we report a new method for femtosecond laser writing of optical-fiber-compatible glass waveguides, namely sp...

Circular dichroism spectroscopy can be optimized to measure the scattering circular dichroism response of a single chiral nanostructure with a single shot.

Advanced photonic tools may enable researchers and clinicians to visualize, track, control, and manipulate biological processes at the single-cell level in space and time. Biological systems are complex and highly organized on both spatial and temporal levels. If biological entities are to be studied, perturbed, engineered, or healed, key-players i...

Optical microfibers finds new applications in various fields of industry, which in turn requires wear resistance, environmental friendliness and ease of use. However, optical microfibers are fragile. Here we report a new method to prolong the microfiber lifetime by modifying its surface with green-extracted graphene overlayers. Graphene films were...

Photonics integrated circuitry would benefit considerably from the ability to arbitrarily control waveguide cross-sections with high precision and low loss, in order to provide more degrees of freedom in manipulating propagating light. Here, we report on a new optical-fibres-compatible glass waveguide by direct laser writing, namely spherical phase...

Advanced photonic tools may enable researchers and clinicians to visualize, track, control and manipulate biological processes at the single-cell level in space and time. Biological systems are complex and highly organized on both spatial and temporal levels. If we are to study, perturb, engineer or heal biological entities, we must be able to visu...

Conventional fabrication methods to produce graphene are cumbersome, expensive and are not ecology friendly. This is due to the fact that a large volume of raw materials requires a large number of acids and alkalis, which in turn requires special disposal. Therefore, it is necessary to develop new technologies or refine existing technologies for th...

Neural networks are one of the first major milestones in developing artificial intelligence systems. The utilisation of integrated photonics in neural networks offers a promising alternative approach to microelectronic and hybrid optical-electronic implementations due to improvements in computational speed and low energy consumption in machine-lear...

The generation of spatial rogue waves, or “hot spots,” is demonstrated experimentally in the passively $Q$ Q -switched Nd:YAG laser system operating in a low-power regime well below the self-focusing limit. Here, we report the dependence of rogue wave statistics on the number of transverse modes that interact in the laser cavity. Our observations s...

Optical waveguides are widely used in integrated photonic circuitry for a variety of applications such as on‐chip lasers, filters, light sources, amplifiers. Such waveguides suffer from high reflection which harms the transparency of the device and, therefore, its efficiency. In article number 2100130, Alina Karabchevsky and her team from the Schoo...

Nature has long inspired scientists and engineers to develop transparent surfaces via constructing anti‐reflective surfaces. In absence of anti‐reflection (AR) coating, silicon reflects about 35% of light for a single interface air−silicon. Here, inspired by jellyfish anti‐reflective eyes, a man‐made anti‐reflective surface on the facet of the wave...

This chapter overviews the principles of the spontaneous emission rate increase, that is the Purcell effect, in relation to the photonic parity-time (PT) symmetry. Being focused on the system of coupled PT-symmetric optical waveguides, we consider behaviors of the Purcell factor in PT-symmetric and broken-PT-symmetric regimes. Surprisingly, excepti...

Chemiluminophores are entities, which exhibit wide-band light emission without any external light source, just caused by a chemical reaction. Since chemiluminescence usually yields to unfavorable competition with other channels of chemical energy dissipation, plasmonic nanoparticles can be employed to enhance the chemiluminescence quantum yield via...

This chapter overviews the principles of the spontaneous emission rate increase, that is the Purcell effect, in relation to the photonic parity-time (PT) symmetry. Being focused on the system of coupled PT-symmetric optical waveguides, we consider behaviors of the Purcell factor in PT-symmetric and broken-PT-symmetric regimes. Surprisingly, excepti...

Passive and active materials platforms are building blocks of an essential element of photonic integrated circuitry (PIC)-waveguide. Due to their small dimensions, waveguides allow miniaturization and design of efficient optical components on a chip. Therefore, choosing the right material for the waveguide is crucial for photonic integrated circuit...

Optical properties of silver nanoparticles obtained via physical vapor deposition on transparent dielectric substrates have been simulated numerically and investigated experimentally. Additional laser treatment of MEC substrate was employed to improve chemical and mechanical stability of the films and made them suitable for chemiluminescence experi...

Correction for ‘Photonic hook formation in near-infrared with MXene Ti 3 C 2 nanoparticles’ by Marat Spector et al. , Nanoscale Adv. , 2020, 2 , 5312–5318, DOI: 10.1039/D0NA00485E

Tuning electric and magnetic response of dielectric structures at the nanoscale is a very important task nowadays. Multipole decomposition is a useful instrument to analyze and then control an opical response. Here we show the way to excite magnetic octupole moment by nanostructuring dielectric scatterer in near-IR spectral range. This response lea...

We study the spontaneous emission rate of a dipole emitter in PT -symmetric environment of two coupled waveguides using the reciprocity approach generalized to non-orthogonal eigenmodes of non-Hermitian systems. Considering emission to the guided modes, we define and calculate the modal Purcell factor composed of contributions of independent and in...

We study the spontaneous emission rate of a dipole emitter in PT-symmetric environment of two coupled waveguides using the reciprocity approach generalized to nonorthogonal eigenmodes of non-Hermitian systems. Considering emission to the guided modes, we define and calculate the modal Purcell factor composed of contributions of independent and inte...

The creation of single photon sources on a chip is a mid-term milestone on the road to chip-scale quantum computing. An in-depth understanding of the extended multipole decomposition of non-isolated sources of electromagnetic radiation is not only relevant for a microscopic description of fundamental phenomena, such as light propagation in a medium...

Semiconductor transistor‐sensors are considered the most widely manufactured device in history. Being invented to switch electronic signals they revolutionized electronics. However, electric switches are hampered by damage from very brief electrical and thermal effects or electromagnetic interference. In article number 2000769, Alina Karabchevsky a...

MXene, a recently developed 2D material, has attracted considerable attention because of its graphene-like but highly tunable properties. It appears that the metallic properties of MXene titanium carbide are pronounced in the near-infrared with well-defined localised surface plasmon resonance (LSPR). Here, we report on the curved photonic nanojet,...

On-chip nanophotonic devices are a class of devices capable of controlling light on a chip to realize performance advantages over ordinary building blocks of integrated photonics. These ultra-fast and low-power nanoscale optoelectronic devices are aimed at high-performance computing, chemical, and biological sensing technologies, energy-efficient l...

In this Letter, we report the experimental observations of a tunable curved photonic nanojet (photonic hook) generated by a 5 µm polydimethylsiloxane microcylinder deposited on a silicon substrate and illuminated by 405 nm laser beam. A moveable opaque aluminum-mask is mounted in front of the microcylinder implementing partial illumination and impa...

Semiconductor transistors for sensors are considered the most widely manufactured device in history. Being invented to switch electronic signals they revolutionized electronics and paved the way for smaller and cheaper sensors, radios, calculators, and computers. However, electric switches are hampered by damage from very brief electrical and therm...

An on-chip optical vortex detector based on spin-Hall nanoslits is reported. The detector is sensitive to the spin of the incoming beam and can simultaneously record the polarization and phase singularity. Although the reported device relies on fast decaying surface plasmons, it represents an important step forward in the development of optical vor...

Molecular overtones stretching modes that occupy the near-infrared (NIR) are weak compared to the fundamental vibrations. Here we report on the enhancement of absorption by molecular vibrations overtones via electromagnetic field enhancement of plasmonic nanoparallelepipeds comprising a square lattice. We explore numerically, using finite element m...

Tuning the near field using all-dielectric nano-antennas offers a promising approach for trapping atoms, which could enable strong single-atom–photon coupling. Here we report the numerical study of an optical trapping of a single Cs atom above a waveguide with a silicon nano-antenna, which produces a trapping potential for atoms in a chip-scale con...

Building blocks of photonic integrated circuitry, optical waveguides, have long been considered transparent. However, the inevitable Fresnel reflection from waveguide facets limits their transparency. This limitation becomes more severe in high-index waveguides in which the transparency may drop to 65%. We overcome this inherent optical property of...

Rapid, sensitive and reliable detection of aromatic amines - toxic manufacturing byproducts - have been previously achieved with molecular vibrations in Mid-infrared (Mid-IR) region. However, Mid-IR spectroscopic tools are hampered by a need to prepare the samples and the sensor cost. Here we develop an affordable label-free sensor on a chip, opera...

Optical forces applied on an object or cell in a non-destructive manner have revolutionised the scientific instruments. The optical tweezers, atomic traps are just two representative examples. Of particular interest for non-destructive manipulation, are curved forces such as photonic hooks, however they extremely weak in a low-contrast media. Here...

In this letter, we report on numerical study, fabrication and experimental observations of tunable photonic nanojet and photonic hook. Here, the curved photonic nanojets (photonic hooks) are generated by single mesoscale microcylinder that we fabricated from polydimethylsiloxane (PDMS), upon its boundary illumination and adjustable area at an incid...

The development of new approaches to tuning the resonant magnetic response of simple all‐dielectric nanostructures is very important in modern nanophotonics. Here, it is shown that a resonant magnetic octupole (MOCT) response can be obtained by dividing a solid rectangular silicon block to a quadrumer structure with the introduction of narrow gaps...

Spatial resolution of conventional optics, which is necessary for nondestructive trapping of micro-objects, is limited by diffraction to a value equal to half of the radiation wavelength. Despite this limitation, using optical methods is one of the main directions in biological and biomedical researches because only these methods have a minimal imp...

Here we use multipole decomposition approach to study optical properties of a silicon nanocylinder in different lossless media. We show that resonant peaks of multipole moments experience red shift, smoothing and broadening. Worth noting that electric multipoles experience bigger red shift than their magnetic counterparts. Our results can be applie...

The ability of all-dielectric nanostructures to perform exotic photonics effects is with superior efficiency compared to their metallic counterparts. Free from joules losses, high-index dielectrics support comparable excitation of electric and magnetic resonances and pave a way to advanced technologies of light energy manipulation. One of the most...

All-dielectric nanophotonics attracts more and more attention nowadays due to the possibility to control and configure light scattering on high-index semiconductor nanoparticles. It opens a room of opportunities for the designing novel types of nanoscale elements and devices, and paves a way to advanced technologies of light energy manipulation. On...

Dielectric nanophotonics is the modern and very relevant field of optics. In this work we use the recently reported Cartesian multipole decomposition approach for all-dielectric metasurfaces [1] to study optical properties of the silicon metasurface at the nanoscale. This metasurface consists of crystalline silicon cubes rotated by 45° around the a...

Tuning the near-field using all-dielectric nano-antennae offers a promising approach for trapping atoms, which could enable strong single-atom/photon coupling. Here we report the simulation results of an optical trapping concept, in which a silicon nano-antenna produces a trapping potential for atoms in a chip-scale configuration. Using counter-pro...

The mid-infrared spectrum can be recorded from almost any material, making mid-infrared spectroscopy an extremely important and widely used sample characterization and analysis technique. However, sensitive photoconductive detectors operate primarily in the near-infrared (NIR), but not in the mid-infrared, making the NIR more favorable for accurate...

Mid-infrared spectrum can be recorded from almost any material making the mid-infrared spectroscopy an extremely important and widely used sample characterization and analytical technique. However, sensitivity photoconductive detectors operate primarily in the near-infrared (NIR) but not in the mid-infrared making the NIR more favorable for accurat...

The development of new approaches to tuning the resonant magnetic response of simple all-dielectric nanostructures is very important in modern nanophotonics. Here we show that a resonant magnetic octupole (MOCT) response can be obtained by dividing a solid rectangular silicon block to an oligomer structure with the introduction of narrow gaps betwe...

Resonant coupling between plasmonic nanoantennas and molecular vibrational excitations is employed to amplify the weak overtone transitions that reside in the near-infrared. We explore for the first time the differential extinction of forbidden molecular overtone transitions coupled to the localized surface plasmons. We show a non-trivial interplay...

Here, we propose the concept of an “optical vacuum cleaner” for optomechanical manipulation of nanoparticles. We utilize a dielectric cuboid to generate an optical gradient force exerted on the nanoparticles for particle’s hovering and trapping. We show that the permittivity contrast between the particle and the nanohole leads to the deep subwavele...

In the Supplementary Material, we prove the validity of the dipole-quadrupole approximation to obtain the conditions of the transverse scattering. The coincidence of the electric dipole Fano profile with the quadrupoles off-resonance and their role in obtaining the transverse scattering phenomenon have been clarified. We also investigate the substr...

We explore the discrete nature of waveguide modes and the effective medium concept to achieve an ultra-compact highly efficient mode conversion device in a high-index platform such as a silicon waveguide. The proposed device is based on a co-directional coupler that has a periodic variation in its refractive index along the propagation direction. T...

All-dielectric resonant nanophotonics lies at the heart of modern optics and nanotechnology due to the unique possibilities to control scattering of light from high-index dielectric nanoparticles and metasurfaces. One of the important concepts of dielectric Mie-resonant nanophotonics is associated with the Kerker effect that drives the unidirection...

For a long time, light manipulation at the nanoscale has been provided primarily with plasmonic materials. However, recent works show that the light can be controlled with dielectric particles. Here, we exploit the asymmetric shape of silicon nanopyramids to control the far-field scattering pattern and the electric field concentration inside the pa...

Resonant coupling between plasmonic nanoantennas and molecular vibrational ex-citations is employed to amplify the weak overtone transitions that reside in the near-infrared. We explore for the first time the differential extinction of forbidden molecular overtone transitions coupled to the localized surface plasmons. We show that a non-trivial int...

Resonant coupling between plasmonic nanoantennas and molecular vibrational excitations is employed to amplify the weak overtone transitions that reside in the near-infrared. We explore for the first time the differential extinction of forbidden molecular overtone transitions coupled to the localized surface plasmons. We show that a non-trivial inte...