Optical and Quantum Electronics最新文献

In this paper the design and implementation of SSW based all-optical NAND and NOR logic gates have been proposed. The design leverages the properties of silicon's high refractive index at optical communication wavelengths (1.55 µm), which ensures low critical angles and enhanced optical confinement in slab waveguides. The gates operate on the interference of the input signals. The designed NAND and NOR logic gates have been optimized for performance in both TE and TM modes using FDTD software MEEP. The NAND logic gate exhibits a contrast ratio of 34.79 dB with a modulation depth of 97.11% for TE mode and 38.42 dB with a modulation depth of 97.11% for TM mode. The NOR logic gate exhibits a contrast ratio of 40.91 dB with a modulation depth of 98.34% for TE mode and 38.42 dB with a modulation depth of 98.60% for TM mode. The designed universal logic gates exhibit high-speed performance, with propagation delay times measured in femtoseconds. The proposed gates exhibit higher performance metrics significantly outperforming existing optical logic gate designs.

Optical devices are an undeniable part of the next generation of information technology. One of the main optical devices required in all structures and systems is an optical waveguide, which is responsible for directing light in desired paths within the circuits of the optical complex. This article aims to design and simulate an optical waveguide combining photonic crystals and plasmonic effects. Thus, a new structure is created using silver rods in a type of dielectric substrate to implement an all-optical waveguide based on plasmonic properties based on the Kerr effect. The waveguide's output spectra for different input power values are simulated and the results show that the Transmission component of the designed plasmonic photonic waveguide is over 95%, thus efficiency is suitable enough for communication systems. Also, the range of minimum changes in input power between 1 to 2.25 w/µm² leads to the tuning of desired wavelengths between 1400 to 1440 nm due to the nonlinearity effect of the structure needed for optical data transmission. The cross-section of the proposed structure is 2178 µm² and it is suitable for optical integrated circuits design.

The NOR gate is widely used in digital circuits that can be used to design logic circuits. In this research, an optical NOR gate has been designed and simulated using a two-dimensional photonic crystal. Most of the work that has been done so far to design logic gates in photonic crystal substrates has used a photonic crystal lattice, including rods in air. In this research, the photonic crystal structure includes holes in the silicon substrate, which is easier to design during fabrication. One of the characteristics of the proposed NOR gate is its simple structure and strong values of 0 and 1, which increase the contrast ratio of the gate (CR = 9.39dB). In other words, the error in detecting high and low values is reduced.

Resonant waveguide grating (RWG) is one of the important devices in optics. Not only was it used as light dispersion equipment, but also RWG was used to enhance the intensity of the electric field on the surface of the device. Some parameters influence to electric field distribution of RWG such as the refractive index of the layers of RWG, the thickness of the layers, the depth of the grating, the period of the grating, and the wavelength of the incident light. In this work, the thickness of the TiO₂ layer on the surface of the RWG was changed while all of the other parameters were fixed. The distribution of the electric field was calculated and the resonant angle was found at the different thicknesses of the TiO₂ layer. The results show that the optimal thickness of the TiO₂ layer is 50 nm at the excitation wavelength of 793 nm. Changing the electric field intensity versus TiO₂ thickness will be discussed in detail. The real RWG was fabricated based on the simulation results for the high transmittance at the wavelength of 793 nm.

As a fundamental technology in quantum information science, spin squeezing possesses immeasurable value in enhancing measurement sensitivity, facilitating the generation of quantum entanglement, accelerating the development of quantum technology applications, and deepening the understanding of quantum mechanics. This paper investigates the generation of spin squeezing in nitrogen-vacancy waveguide systems within non-Markovian thermal environments. We derive a non-Markovian master equation that characterizes this system and conduct numerical simulations to illustrate the effects of memory parameters and the number of spin particles on generating maximum squeezing. Our study provides insights into spin-integrated magnetic measurements and the application of spin qubits in phonon-mediated quantum information processing.

Optical Burst Switching (OBS) offers a promising solution for efficient bandwidth utilization in optical networks. This study aims to enhance burst assembly and scheduling in OBS networks using deep learning and optimization techniques. The research begins with data collection, focusing on key OBS network parameters such as packet counts, burst sizes, and traffic patterns. The DualAutoNet model, incorporating autoencoders, Convolutional Neural Networks (CNNs), and Recurrent Neural Networks (RNNs), is then employed to optimize burst assembly. For optimal channel scheduling, a novel hybrid optimization method, the Marine Swarm Optimization Algorithm (MSOA) which combines Tuna Swarm Optimization (TSO) and Tunicate Swarm Algorithm (TSA) is introduced. Additionally, a multi-objective optimization-based route queuing protocol is developed, accounting for latency, energy consumption, throughput, and distance. The MSOA is utilized to determine the best routes for efficient network resource management in OBS networks. The proposed model's performance is compared to existing methods, including Particle Swarm Optimization (PSO), Ant Colony Optimization (ACO), Tunicate, and Tuna algorithms. Implemented using MATLAB, key performance indicators such as energy consumption, network lifetime, throughput, and packet delivery ratio are evaluated under varying node conditions. This paper presents a detailed comparative analysis of the results, demonstrating the proposed model's superiority in reducing latency, increasing throughput, and minimizing packet loss.

Monitoring of benzo[def]phenanthrene as a toxic component is essential for environmental assessment because of its adverse impact on human health and ecological systems. P-Toluenesulfonic acid-doped polyaniline (PANI) and PANI-graphene quantum dot (PANI-GQD) nanocomposites were fabricated by incorporating graphene quantum dot (GQD) concentrations between 100 and 500 ppm through oxidative chemical polymerization of aniline under acidic conditions at ambient temperature. The materials were analysed using Fourier transform infrared (FT-IR), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), thermogravimetry analysis (TGA), UV–visible and photoluminescence (PL) spectroscopy, and electrical conductivity measurements. Key findings included significant shifts in FT-IR peaks (C=N stretching from 1651 to 1694 cm⁻¹) and an increase in the AB/AP ratio from 0.27 to 0.333, indicating enhanced sp² hybridization and improved electrical conductivity. XRD analysis showed improved molecular ordering in PANI-GQD nanocomposites. FE-SEM revealed changes in morphology from flat layers to spherical and flaky mixtures with increasing GQD concentrations. Film thickness increased from 13.52 μm (PANI-GQD-1) to 30.07 μm (PANI-GQD-5). The PANI-GQD-3 nanocomposite exhibited the lowest bandgap (2.39 eV) and the highest PL intensity because of enhanced energy transfer between PANI and GQD. Electrical conductivity decreased with increasing GQD concentration, with PANI-GQD-5 showing 2.17 (Ω cm)^–1. PANI-GQD-3 successfully detected benzo[def]phenanthrene at concentrations ranging from 0.001 mol L⁻¹ to 10 × 10⁻⁹ mol L⁻¹ with a limit of detection of 1.5 × 10⁻⁹ mol L⁻¹ through gas chromatography. Results demonstrated the potential of PANI-GQD nanocomposites for sensor and biosensor applications.

This study conducted a comprehensive characterization of the surface and electronic properties of nanograting patterns on a silicon substrate using SEM, EDX, AFM, and XPS techniques. SEM images confirmed well-shaped and periodic nanograting patterns with determined depths (10 nm, 20 nm, or 30 nm) created by the laser interferometry lithography process. EDX elemental mapping confirmed that the surface of the patterns was predominantly silicon, with no significant contaminants such as oxygen or carbon present. AFM topography revealed a uniform surface roughness of up to 5 nm and well-aligned periodic patterns. XPS surface composition spectra, obtained after reactive etching, indicated no metal oxide formation or organic contamination and a clear Si spectrum. XPS scans for low binding energy (0–20 eV) were recorded to extract the valence band (VB) of the patterned surface for three different indent depths. The valence band offset from the valence band edge (E_f-E_v) was calculated to be 0.2 eV for 10 nm, 0.8 eV for 20 nm, and 0.4 eV for 30 nm indents, suggesting that a 20 nm indent depth provided the highest VB offset and thus was the preferred depth to obtain enhanced conductivity of the patterned surface. The comprehensive analysis highlighted the optimal indent depth for improved surface conductivity of nanograting-patterned silicon substrates.

In this paper, a graphene-dielectric metasurface is proposed for effective optical biosensing. The structure is composed of a periodic array of double-slit split-ring resonators (SRRs) adjacent to silicon bars over a sheet of graphene and silicon dioxide substrate. Interactions between electric dipoles (bright modes) in silicon bars and magnetic dipoles (dark modes) excited in SRRs lead to a high quality factor resonance based on the phenomenon of electromagnetically induced transparency (EIT). High electric field confinement is achieved within the two gaps of SRRs at the resonance frequency, which result in strong light-analyte interaction. The structural parameters of the proposed metasurface are optimized to achieve the best performance. The biosensor is analyzed using the finite-element method (FEM) and the results are presented. Owing to the high Q-factor EIT resonance and the enhanced light-matter interaction inside the gaps, a high sensitivity of 496 nm/RIU and figure-of-merit (FOM) of as high as 741 RIU⁻¹ are achieved that are higher than those reported in recently published works. The resolution and the linearity R² value of the proposed biosensor are calculated to be 2.02e-4 and 0.999, respectively. The reported characteristics could be promising for sensing of various biomolecules such as hemoglobin.

This work studies the bifurcation analysis, phase portrait, and dynamics behavior of exact traveling wave solutions for the time M-fractional (3 + 1)-dimensional Painlevé integrable model. This model is used to describe some complex phenomena in nonlinear science and is crucial for addressing various practical challenges, including key models in areas like quantum mechanics, statistical physics, nonlinear optics, and celestial Mechanics. By bifurcation theory, we find the phase portrait of the proposed model. Bifurcation analysis in the proposed systems helps figure out how small changes in parameters can cause big changes in how the system behaves, like going from stable states to chaotic dynamics. It pinpoints critical thresholds where these transitions occur, aiding in the prediction and control of complex behaviors. We also present some traveling wave solutions according to the phase portrait orbit. Furthermore, the exact traveling wave solutions of the time M-fractional (3 + 1)-dimensional Painlevé integrable model are investigated by using the modified simple equation technique. This method provides the solutions directly without any predefined solutions. Under the condition, the solutions are real and complex valued in terms of exponential, trigonometric, and hyperbolic function form. For the special ideals of free parameters, we will include the bright bell wave, dark bell wave, interaction of kink and periodic lump wave, double periodic wave, double dark bell wave, and so on. By visualizing, the three, two-dimensional and density diagrams, the dynamic properties of the proposed model are examined and illustrated, enhancing the comprehension and application of time M-fractional (3 + 1)-dimensional Painlevé integrable model.