Optical and Quantum Electronics最新文献

In this study, we investigate the influence of Distributed Feedback (DFB) lasers on the performance of Erbium-Doped Fiber Amplifiers (EDFA) and explore the EDFA system using coupled mode equations. Our primary objective is to minimize amplified spontaneous emission (ASE) while maintaining a high gain (G). Key factors affecting gain, such as pump power (P_p), erbium doping radius (R_d), EDFA length (L_EDFA), and input signal power (P_s), are analyzed analytically. We examine the propagation behaviour of ASE, gain trends, population inversion, pump signal, and input signal. To mitigate ASE, Fiber Bragg Grating (FBG) is employed. The DP-FBG EDFA configuration demonstrated a gain improvement of 3 dB and a reduction in ASE power by approximately 4 dBm compared to the SP-EDFA configuration. Further comparisons were made across different wavelengths in the C-band, revealing that the optimized EDFA-FBG configuration outperforms the initial setup. Further, out of all the four lasers in C-band, 1550 nm DFB laser maintains Q-6 for longer fiber length with an EDFA having L_opt of 10.52 m, R_d-opt of 2.2 µm and P_sat of − 22.43 dBm. Additionally, the quality factor was assessed, showing that the optimized configuration maintains a higher quality factor. Notably, using FBG as a filter allowed the maintenance of Q-6 over 100 km, whereas an inverted Gaussian filter sustained Q-6 only over 40 km.

Theoretical investigation on Hermite higher-ordered cosh-Gaussian (H-Hch-G) laser pulses to explore their potential for effectively vacuum electron acceleration. The Hermite polynomial function with mode indices (n, l), decentered parameter (b) governed cosine-hyperbolic function, its higher-order (m), and Gaussian beam function all affect the propagation properties of these distinct laser pulses. With an order of ‘m’ varying from 0 to 3, they are categorized as HG, H-cosh-G, H-(cosh)²-G, and H-(cosh)³-G functioned laser pulses. It is suited for long-distance propagation because the beam profile departs its initial maximum intensity centre more slowly and becomes flatter as ‘m’ increases. Upon changing ‘b’, the property’s characteristics changes from ring-shaped (b ~ 2) and flat top (b > 1) to Gaussian (b = 0). Consequently, it functions sufficiently to quickly accelerate electrons to incredibly high energies. According to analytical findings, there is a large increase in electron energy in GeV regime with intensity peak ~(:{10}^{20}text{W}/{text{c}text{m}}^{2}) of laser in vacuum when the mode indices (n, l), m and b are altered.

Semiorganic single crystal of bisglycine cobalt chloride dihydrate (BGCCD) is a superior material for non-linear optics (NLO) applications such as photonic, electronic and opto-electronic devices. This article presents high-quality BGCCD single crystals prepared using the slow evaporation solution technique (SEST), which are a famous NLO material. A transparent BGCCD crystal with a maximum size of 9 × 9 × 8 mm³ was collected over the period of 80 days. Various analyses were conducted on the grown crystals, including single crystal x-ray diffraction, which was utilized to find out the unit cell parameters. Analyses of functional groups using Fourier transform infrared spectroscopy. Finding the band gap and absorbance of the grown crystal is done using UV-Visible spectroscopy. Mechanical stability is determined by micro-hardness. The dielectric loss and dielectric constant of the grown crystal is found by utilizing dielectric measurements. The stability is found through thermo-gravimetric and differential thermal analyses. To detect surface flaws in the grown crystals, etching analysis was employed. Structure morphology was identified using a scanning electron microscope. The elements were identified using energy dispersive x-ray analysis. The excitation and emission spectra can be determined using photoluminescence, and in order to determine the crystal’s thermal diffusivity, photoacoustic spectroscopy was employed. The findings regarding thermal diffusivity indicate that it is well-suited for uses related to opto-electronic devices.

The current study presents six D-π-A configured non-fullerene acceptor chromophores (BTI1-BTI6) derived from benzotriindole compound end-capped with hexyldicyanovinyl groups, referred to as BTI (2 T-DCV-Hex)₃, through structural tailoring of different terminal acceptors. Optoelectronic characteristics of newly designed chromophores were determined via DFT study at B3LYP/6-31G (d,p) functional. Various analyses such as frontier molecular orbitals, density of states (DOS), transition density matrix (TDM), binding energy (E_b), and open circuit voltage (V_oc) were conducted. All the derivatives exhibited a comparable band gap (2.45–2.70 eV) manifesting absorption bands in the UV-Visible spectrum (590–463 nm), in solvent as well as in gaseous phase. Interestingly, smaller E_b values of 0.170 and -0.099 eV were observed for BTI5 and BTI6, respectively, suggesting a greater degree of charge transfer and improved exciton dissociation in these derivatives. These findings are further supported by TDM and DOS analyses, which confirm that all the studied compounds exhibit a higher charge transfer rate from highest occupied orbital to lowest unoccupied orbital (HOMO to LUMO). In conclusion, the good photovoltaic response observed for all the compounds suggests that these chromophores are reasonable candidates for development of efficient organic solar cells.

Metamaterials for refractive index sensing applications have garnered significant attention in recent years. However, achieving an optimal balance between high sensitivity and quality factor, which together determine the Figure of Merit of sensors, necessitates extensive optimization efforts. In this paper, we present the metaheuristic optimization of a refractive index-based plasmonic sensor operating at a wavelength of 1500 nm, which has the potential to open new avenues for applications in biomedical sensing and beyond. Particle Swarm Optimization is utilized to maximize the performance of the proposed infrared metamaterial sensor. The proposed design features two overlapping E-shaped silver patches placed on top of a grounded (mathrm {Al_{2}O_{3}}) substrate. This configuration results in a narrow-band absorption spectrum with peak resonances caused by the confinement of the electric field within the gaps of the E-shaped metallic arms. The metaheuristic optimization process yielded sensor dimensions that achieve a high sensitivity of 834.7 nm/RIU,Q = 865 and a Figure of Merit of 481.34 (textrm{RIU}^{-1}), demonstrating outstanding performance in cancer cell detection.

This paper introduces a new controllable anomalous hollow cosh-Gaussian beam (CAHcGB). Based on the Snyder-Michell model and the ABCD matrix description of strongly nonlocal nonlinear media (SNNM), we investigate the transmission characteristics of CAHcGB. Analytical expressions for the electric field, beam width, wavefront curvature radius, and critical power of CAHcGB in SNNM are derived. The results demonstrate that CAHcGB undergoes periodic evolution during transmission in SNNM, influenced by both the beam parameters and the initial beam power. When the critical power equals the incident power, the beam width remains unchanged throughout transmission, resembling a CAHcGB soliton; otherwise, it periodically changes, akin to a breather. The study also reveals that the on-axis intensity evolution curve can exhibit various shapes such as concave, platform, or Gaussian-like, depending on the input power. The research results hold significant potential for applications in optical fiber communication systems, all-optical networks, and optical switches.

One of the primary challenges faced by visible light communication (VLC) systems employing optical orthogonal frequency division multiplexing is the peak-to-average power ratio (PAPR). This study is dedicated to designing, simulating, and evaluating bit error rate (BER) and PAPR reduction methods tailored for the VLC broadcasting system. The asymmetric clipped optical orthogonal frequency division multiplexing (ACO-OFDM) scheme is highlighted in this work for its impressive performance. Therefore, the proposed PAPR mitigation methodologies applied to ACO-OFDM. The proposed PAPR reduction strategy involves 5 distinct precoding methodologies. The PAPR was mitigated by 3.485 dB after applying the DST precoding methodology. Still, the WHT precoding methodology can achieve PAPR reduction by 1.131 dB, without BER performance degradation, with respect to the conventional ACO-OFDM system. Furthermore, the work addresses another challenge in VLC systems: the bit error rate (BER). This is accomplished by introducing approaches to Time Domain Noise Cancelation and Frequency Domain Noise Cancelation (FDNC). The BER performance of these 2 receiver models is nearly the same. The simulation results indicate the system performance enhancement after applying noise cancellation approaches by 1.65 dB at the 4-QAM modulation scheme and 2.97 dB at the 1024-QAM modulation scheme. The 16-QAM modulation scheme, after applying DST and WHT methodologies alongside noise cancellation approaches, can enhance both PAPR by 20.83% and 6.76%, but the E_b/N₀ performance enhancement by 10.10% and 14.64%, respectively. Additionally, the effectiveness and validity of the proposed schemes are verified by comparing them with relevant literature reviews on PAPR reduction techniques and selecting an optimal choice among them.

Nickel sulfide nanoparticles were successfully synthesized through a meticulous process involving a well-mixed powder of Ni(CH₃COO)₂∙2H₂O and Thiourea. The X-ray diffraction analysis provided insights into the structural nature of NiS, revealing its polycrystalline characteristics with a hexagonal system. This information is fundamental, as it forms the basis for understanding the material’s behavior and functionality in various applications. Determining the average values of mean crystallite size, microstrain, and dislocation Nickel sulfide nanoparticles were successfully synthesized through a careful process involving a well-mixed powder of Ni(II)₂∙2H₂O and Thiourea. The X-ray diffraction analysis provided insights into the structural nature of NiS, revealing its polycrystalline characteristics with a hexagonal system. This information is crucial as it forms the basis for understanding the material’s behavior and functionality in various applications. Determining the average values of mean crystallite size, microstrain, and dislocation density for the (100) plane (32.62 nm, 0.000296, and 0.000939 nm-2, respectively) contributes to a comprehensive understanding of the material’s structural features. The photoluminescence spectrum of NiS in the visible region revealed split peaks at 405.8 and 428.25 nm, shedding light on the radiative recombination process between electrons and holes. The confirmation of thermal stability through a thermogravimetry diagram is essential for applications in elevated temperature environments, ensuring the material’s reliability under varying conditions. Analyzing the stoichiometry of NiS using energy dispersive spectroscopy attached to transmission electron microscopy provides insights into the material’s composition. Cyclic voltammetry results indicating a diffusion coefficient greater than that of NiS added to carbon hold significance for electrochemical applications. The unique characteristic peaks observed in cyclic voltammetry for fuel cell applications suggest the potential use of NiS in energy conversion technologies, broadening its scope of application. The confirmation of NiS’s ability to elucidate the physical and electronic properties of electrochemical systems through electrochemical impedance spectroscopy underlines its importance as a versatile material in various research and practical domains.