arXiv subjects

Aviad Katiyi

Publications and source records attributed to Aviad Katiyi.

5 recordsLinked to original sources

arXiv2025

Bound-state-in-the-continuum (BIC) induced narrow resonances in MXene-coated absorptive dielectric metasurfaces for Methane sensing

Strong light confinement is highly necessary for various applications, including sensing. MXene, a novel and emerging material with a broadband plasmonic response, has been highly utilized in electronic sensing systems, as well has garnered significant attention for its applicability in photonics. The loss imparted by MXene can be overcome through the Bound States in Continuum (BIC) physics. In this work, we report two important designs of a hybrid metasurface, comprising a silicon nanodisk metasurface and MXene. In both designs, narrow and high absorption resonance of quality factor of $\sim$150 is attained, where MD is the dominant multipole, governed by symmetry-protected BIC. Both hybrid metasurface designs are optimized to exhibit narrow resonance in the vicinity of 1650 nm with an absorption greater than 90 $\%$. The origin of high absorbance in such a hybrid metasurface is attributed to the momentum matching by the spacer layer of $SiO_2$. The spectral characteristics of the designed metasurface can be utilized for first overtone spectroscopy of Methane gas. Numerical simulations yield a bulk refractive index sensitivity of 171 nm/RIU with FOM = 17.56 $RIU^{-1}$ and sensitivity for Methane gas, S = 0.8 nm per unit percentage concentration, when a Cryptophane-E layer is used.

physics.optics↗

arXiv2025

Quantum photonics on a chip

Optical chips for quantum photonics are cutting-edge technology, merging photonics and quantum mechanics to manipulate light at the quantum level. These chips are crucial for advancing quantum computing, secure communication, and precision sensing by integrating photonic components like waveguides, beam splitters, and detectors to manipulate single photons, the fundamental carriers of quantum information. Key advancements in optical chips include low-loss waveguides, efficient single-photon sources, and high-fidelity quantum gates, all essential for scalable quantum circuits. Integrating these circuits on a chip offers significant advantages in miniaturization, stability, and reproducibility over traditional bulk optics setups. Recent breakthroughs in materials science and nanofabrication have propelled the field forward, enabling the production of chips with higher precision and lower defect rates. Silicon photonics, in particular, has become a prominent platform due to its compatibility with existing semiconductor manufacturing processes, facilitating the integration of quantum photonic circuits with classical electronic systems. Here, we share our vision of the future of optical chips for quantum photonics, which hold promise for various applications. In quantum computing, they enable the development of compact and scalable quantum processors. In communication, they provide the foundation for ultra-secure quantum networks through quantum key distribution. In sensing, they allow for high-precision measurements that surpass classical limits. As research progresses, optical chips are expected to play a critical role in realizing the full potential of quantum technologies.

quant-ph↗

arXiv2022

On-chip beam rotators, adiabatic mode converters, and waveplates through low-loss waveguides with variable cross-sections

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-fibre-compatible glass waveguides, namely spherical phase induced multi-core waveguide (SPIM-WG), which addresses this challenging task with three dimensional on-chip light control. Fabricating in the heating regime with high scanning speed, precise deformation of cross-sections is still achievable along the waveguide, with shapes and sizes finely controllable of high resolution in both horizontal and vertical transversal directions. We observed that these waveguides have high refractive index contrast of 0.017, low propagation loss of 0.14 dB/cm, and very low coupling loss of 0.19 dB coupled from a single mode fibre. SPIM-WG devices were easily fabricated that were able to perform on-chip beam rotation through varying angles, or manipulate polarization state of propagating light for target wavelengths. We also demonstrated SPIM-WG mode converters that provide arbitrary adiabatic mode conversion with high efficiency between symmetric and asymmetric non-uniform modes; examples include circular, elliptical modes and asymmetric modes from ppKTP (periodically-poled potassium titanyl phosphate) waveguides which are generally applied in frequency conversion and quantum light sources. Created inside optical glass, these waveguides and devices have the capability to operate across ultra-broad bands from visible to infrared wavelengths. The compatibility with optical fibre also paves the way toward packaged photonic integrated circuitry, which usually needs input and output fibre connections.

physics.optics↗

arXiv2021

Super-resolution imaging and optomechanical manipulation using optical nanojet for non-destructive single-cell research

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 visualize key players in such systems and to track, control and manipulate them precisely and selectively. To achieve this goal, the engineering of non-destructive tools will allow us to interrogate and manipulate the function of proteins, pathways and cells for physicians, enabling the design of 'smart materials' that can direct and respond to biological processes on-demand. Among the potentially exploitable non-destructive tools, light-based actuation is particularly desirable, as it enables high spatial and temporal resolution, dosage control, minimal disturbance to biological systems and deep tissue penetration. Here, we overview existing approaches toward the engineering of light-activated tools for the interrogation and manipulation of single-cell processes, and list the types of studies and types of functions that can be controlled by light. Timely applications, such as studies of inflammation and of crossing brain barrier systems - via super-resolution imaging and optomechanical manipulation - are two representative examples of emerging applications so far never addressed.

physics.optics↗

arXiv2021

Ti$_3$C$_2$T$_x$ MXene Enabled All-Optical Nonlinear Activation Function for On-Chip Photonic Deep Neural Networks

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-learning tasks. However, at present, most of the neural network hardware systems are still electronic-based due to a lack of optical realisation of the nonlinear activation function. Here, we experimentally demonstrate two novel approaches for implementing an all-optical neural nonlinear activation function based on utilising unique light-matter interactions in 2D Ti$_3$C$_2$T$_x$ (MXene) in the infrared (IR) range in two configurations: 1) a saturable absorber made of MXene thin film, and 2) a silicon waveguide with MXene flakes overlayer. These configurations may serve as nonlinear units in photonic neural networks, while their nonlinear transfer function can be flexibly designed to optimise the performance of different neuromorphic tasks, depending on the operating wavelength. The proposed configurations are reconfigurable and can therefore be adjusted for various applications without the need to modify the physical structure. We confirm the capability and feasibility of the obtained results in machine-learning applications via an Modified National Institute of Standards and Technology (MNIST) handwritten digit classifications task, with near 99% accuracy. Our developed concept for an all-optical neuron is expected to constitute a major step towards the realization of all-optically implemented deep neural networks.

physics.optics↗