Optical and Quantum Electronics最新文献

A newly developed metamaterial absorber (MTMA) is proposed in this study for use in electromagnetic interference (EMI) shielding for stealth-related applications. The structure employs a symmetric layout with a thunder cross pattern, enhancing its exceptional absorption capabilities. The metamaterial absorber unit cell is fabricated using an FR4 substrate, with its dimensions measured as (0.28lambda _0 times 0.28lambda _0 times 0.02lambda _0), based on a reference wavelength (lambda _0) calculated at 10.76 GHz. The designed metamaterial absorber (MA) demonstrates nearly complete absorption, peaking at 99.99% at 10.76 GHz for both transverse electric (TE) and magnetic field (TM) orientations under normal incidence. The absorption mechanism of the MTMA is examined through an integrated approach involving its structural design, metamaterial traits, ECM formulation, and the characterization of surface current responses, electrical and magnetic field vectors. Moreover, the designed absorber sustains strong absorption characteristics under TE and TM mode excitations across varying incidence angles as high as (60^circ). The designed MA exhibits a shielding performance, ensuring a shielding effectiveness exceeding 60 dB throughout the entire band in both simulated and experimental conditions. This effectively reduces RF signal strength, minimizing the influence on devices prone to electromagnetic interference. To validate the analytical simulation results, the designed MA was fabricated as well as tested. The match in comparison of the measured and simulated data demonstrates its suitability for EMI shielding in the microwave regime.

This research utilizes first-principles density-functional theory (FP-DFT) and provides a comprehensive analysis of Mg₃NCl₃ inorganic halide perovskites’ structural, electrical, mechanical, and optical properties. This investigation advances our understanding of the physical properties of Mg₃NCl₃, along with the influence of spin-orbital coupling (SOC) and strain effect. Mg₃NCl₃ has a thermodynamically stable crystal structure, which is confirmed by the positive phonon frequencies. The planar Mg₃NCl₃ molecule presents an indirect bandgap, E_g of 2.305 eV (PBE) without SOC, which reduces to 2.262 eV (PBE) at the Γ and R-point due to subjective SOC effects, while demonstrating E_g expansion with compressive strain and contraction while the strain is tensile. The changes in the E_g further modify the optical features, which are assessed by evaluating dielectric functions, absorption, extinction coefficient, reflectivity, refractivity, and loss function. The E_g reduced to 1.271 eV without SOC and 1.204 eV with SOC at + 6% strain, which enhances the exceptional optical properties by shifting them towards the visible range with improved optical responses that render them particularly suitable for photovoltaic and optoelectronic applications. Mg₃NCl₃ exhibits excellent mechanical stability, with a high elastic constant and moduli, highlighting its strength and rigidity. Its mechanical properties improve under compressive strain, while they experience a slight decrease under tensile strain. The material is also ductile and anisotropic in response to different types of strain. Additionally, its thermal properties indicate that it can withstand high temperatures. These findings suggest that Mg₃NCl₃ holds great promise as a cost-effective, high-performance, and non-toxic material for use in electrical devices, particularly in applications like solar cells and photovoltaic technology.

This paper presents a comprehensive numerical study of vacuum electron acceleration driven by Hermite–cosh–Gaussian (HcG) laser pulses, emphasizing beam structure control as a route to enhance the efficiency and scalability of direct laser acceleration (DLA). The combined influence of the Hermite index ((:s)), cosh–Gaussian decentered parameter ((:b)), linear chirp parameter ((:C)), and polarization state is systematically analyzed. The simulations reveal three distinct acceleration stages governed by a phase synchronization process, with the quasi-static phase identified as the regime of maximal energy transfer. Importantly, it is demonstrated that an optimally tailored linear chirp can dramatically enhance energy gain, and tuning the parameter (:b) leads to improved field localization and extended synchronism, yielding peak energies up to (:approx:8:text{GeV}). A decisive role of polarization is revealed: circular polarization not only maximizes energy transfer but also suppresses sensitivity to the initial phase, thereby ensuring stable and reproducible acceleration. Furthermore, higher-order HcG modes are shown to expand the effective injection window, allowing even off-axis electrons to reach substantial energies. These findings demonstrate that chirped HcG beams, through polarization- and chirp-controlled beam structure, offer a versatile and efficient driver for compact next-generation laser-based accelerators.

A complementary split ring resonator (CSRR)-based microstrip patch sensor is presented for noninvasive estimation of blood glucose concentration. The device employs a triangular patch with a CSRR etched in the ground plane to realize two ISM bands: 2.42–2.62 GHz for wireless telemetry and 5.17–5.24 GHz for sensing, where the structure operates as a microwave resonator. Geometry and feed parameters were optimized to sharpen the S-parameter response and improve glucose-dependent sensitivity. A multilayer human-thumb phantom was constructed, and blood glucose level was swept from 100 to 300 mg/dL to quantify frequency-selective detection while complying with safety constraints. Changes in glucose level alter the tissue permittivity in the resonator-finger configuration, resulting in measurable shifts in resonant frequency and S₁₁ magnitude, which enables a dual-parameter readout. The prototype exhibits frequency sensitivity of 160 kHz/mg·dL⁻¹ and magnitude sensitivity of 0.0654 dB/mg·dL⁻¹. The sensor was fabricated using conventional PCB etching to validate the simulated design. The measured S-parameters closely follow simulations with minor deviations attributable to fabrication tolerances and tissue-model simplifications. Specific absorption rate (SAR) analysis yields 0.397 W/kg averaged over 1 g of tissue, within commonly accepted IEEE exposure limits. The compact, low-cost, dual-band architecture and dual-parameter sensing indicate strong potential for real-time, noninvasive glucose monitoring and future integration into wearable systems.

This paper presents a novel realization of Surface Plasmons (SPs)–induced Optical Bistability (OB) in Partially Reduced Graphene Oxide (PRGO) deposited on a gold thin film. The novelty comes from the distinct mechanism of exciting SPs by Difference Frequency Generation (DFG) using a pump–probe radiation in the visible range as well as the dynamical tuning mechanism of OB via an external bias voltage (2.5 V) which in turn, provides an active control over the nonlinear response and leads to an unprecedented ultra-low threshold OB (a few miliwatts). Our EFM images reveals that Graphene Quantum Dots (GQDs) are formed in consequence of the reduction process which are responsible for the strong localization of SPs. Accordingly, we develop a theoretical model to explain the unexplored SPs effect on the OB enhancement through strengthening the internal feedback while no external feedback process is deployed. On the other hand, our density functional calculations unveils that the PRGO first order hyperpolarizability is at least one order higher than that of the pristine graphene. Our findings highlight PRGO as an alternative semiconducting platform for tunable, reconfigurable and energy efficient computing components like electro-optical switches, memristors and gates.

Quantum remote state preparation (QRSP) is an area of quantum communication where a sender transmits an arbitrary qubit—whose coefficients are predetermined—to a receiver. This process relies on entanglement and classical communication, eliminating the need to directly send the quantum state itself. In this research, three new schemes for controlled quantum remote state preparation are presented. All three proposed schemes use entanglement swapping to enhance security and allow destination changeability for each sender’s qubit. Additionally, in these schemes, there is no communication between users in either the quantum or classical channels. In the first protocol, there are three senders and three receivers. The objective of this scheme is to transmit three known qubits from the senders to the receivers, with the destination of each qubit not pre-determined. Throughout the protocol, each sender specifies the receiver to the controller, who then performs the necessary measurements to ensure the transmissions are feasible. The second protocol builds upon the initial one, extending the number of senders and receivers to an arbitrary value, (:n). The third scheme is an extension of the first two, featuring (:n) senders and (:n) receivers, with the added capability that each user can act as both a sender and a receiver, and their roles can change throughout the scheme. The correctness of the protocol is verified in Qiskit and is analyzed in noisy environment. The use of entanglement swapping and the lack of communication between users ensures that the communication is secure and private. The ability to dynamically change the roles of users and the destination of qubits ensures high security, flexibility, and scalability, opening up numerous possibilities in the rapidly evolving field of quantum technology.

This study examines the capabilities of a one-dimensional photonic sensor for detecting glucose concentration levels of aqueous solutions in the visible region of the electromagnetic spectrum. This design works on the principle of Tamm-Fano resonance due to a plasmonic thin layer of metallic aluminium mounted on the top of a Distributed Bragg Reflector (DBR). The DBR structure is composed of alternating high and low refractive index layers of materials (TiO_2) and (MgF_2), respectively. An air cavity consisting of a microfluidic cell is integrated between the Al layer and the DBR to facilitate analyte detection. The entire analysis of reflection spectra is carried out in the visible region of the electromagnetic spectrum, extending from 450 to 750 nm. The simulation results are obtained by using MATLAB and COMSOL Multiphysics 6.0 software. Our design under s-polarisation oblique incidence case exhibits impressive performance metrics, showing a maximum sensitivity of 562.6349 nm/RIU, a quality factor of 347.7686, and a figure of merit of 357.6827 at AOI (40^{circ }). Our findings suggest that the proposed structure offers superior performance in contrast to the existing photonic designs, especially in the visible region of the spectrum. The proposed idea may be used for the development of future photonic devices suitable for biosensing applications, chemical and gas detection in the visible region of the spectrum.

As an optical elastic imaging technique, Brillouin scattering spectroscopy offers the significant advantages of being non-destructive, label-free, and non-contact, making it a powerful tool for characterizing material properties in materials science and biomedicine. Stimulated Brillouin scattering (SBS) spectroscopy, particularly when implemented with pump-probe technology, provides superior spatial resolution and faster image acquisition rates, enabling high-speed and high-precision extraction of material mechanical properties. This paper introduces the theoretical background of SBS spectroscopy and comprehensively analyzes key factors influencing its detection performance based on the pump-probe approach, including modulation-locking optical detection paths, pump-probe beam angle, effective interaction length, and temperature. Furthermore, the applications of this technique in characterizing both conventional dielectric materials and biomedical specimens are summarized. We systematically investigate the background, the basic principles, the spectroscopy detection structure, the influencing factors, and applications of SBS, which is intended to serve as a reference and guide for the optimization and application of SBS spectral detection.

Perovskite light-emitting diodes (PeLEDs) are emerging candidates for efficient lighting and display applications, but their external quantum efficiency is limited by photon trapping and non-ideal recombination. In this work, we introduce an optoelectronic modeling approach that simultaneously accounts for carrier transport, recombination, and optical outcoupling through multiple dipole sources distributed according to the spontaneous emission profile. This method enables the consistent evaluation of both internal quantum efficiency and light extraction efficiency as functions of perovskite thickness and applied bias. The results reveal a thickness-dependent trade-off: thinner layers favor higher light extraction efficiency (up to η_LE ~ 15% at 36 nm). Whereas, thicker layers support larger internal quantum efficiency (up to η_IQE ~ 59.8%). Notably, the maximum internal quantum efficiency (η_IQE) typically occurs near the diode turn-on voltage (V_on), which increases with the thickness of the perovskite, shifting to a bias where both internal and external quantum efficiencies reach their peak. Consequently, the external quantum efficiency reaches η_EQE ~ 9.0% at 36 nm and V_on ~ 2.34 V, while the absolute maximum of η_EQE ~ 9.46% appears for a 51-nm thick perovskite layer and V_TO ~ 2.5 V. These findings highlight the necessity of considering electronic and optical effects, providing realistic guidance for optimizing PeLED performance. In particular, they indicate that a careful choice of the perovskite layer thickness alone can substantially enhance device efficiency, even before pursuing more complex optimization strategies.

This study presents a comprehensive computational investigation of the electronic, optical, and charge-transport properties of six novel donor-acceptor-donor (D–A–D) organic dyes designed for dye-sensitized solar cells (DSSCs). These dyes exhibit properties comparable to those of the widely studied D–A and D–(pi)–A architectures. Using Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT), key parameters including frontier molecular orbitals, reorganization energies, charge-transfer integrals, and photovoltaic characteristics were systematically evaluated. The dyes display narrow band gaps (1.88–2.83 eV), strong absorption in the visible to near-infrared region, and efficient intramolecular charge transfer. Notably, the TPA-SDP-TPA dyes show high electron mobility on the order of 0.396 (hbox {cm}^2)/Vs. The open-circuit voltage ((V_textrm{OC})) values range from 1.042 V to 2.001 V, with PTHHCB-BCS-PTHHCB achieving the highest (V_textrm{OC}). Adsorption studies on a (hbox {TiO}_{2}) cluster reveal strong interfacial interactions, with adsorption energies of (-5) to (-2) eV for the anchored dyes, facilitating effective electron injection into (hbox {TiO}_{2}) conduction band.