查看更多>>摘要：In this present work, reactive co-sputtering (DC) has been used to deposit the pure ZnO and Cu-doped ZnO (Cu-ZnO) thin films on a glass substrate. The copper atoms are subsumed into ZnO thin film by co-sputtering(RF) of a pure copper target. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Raman spectroscopy, Photoluminescence spectroscopy (PL), UV-Visible spectroscopy, and ellipsometry were used to examine pure ZnO and Cu-doped ZnO thin films. XRD reveals the wurtzite crystal structure for both pure and Cu-doped ZnO thin films. FESEM images show the dense and uniform surface morphology of all thin films. Energy-dispersive X-ray analysis (EDS) confirms the uniform distribution of copper dopant and variation in doping percentage in the Cu-doped ZnO films. The PL spectra of Cu-doped ZnO film have strong violet emission which shows a variation in zinc vacancy (V-Zn) defect density levels. UV-Vis-NIR spectroscopy has confirmed a slight increase in optical band gap by copper doping. The refractive index, roughness, and film thickness have been calculated using spectroscopic ellipsometry and found to increase with Cu doping concentration.
查看更多>>摘要：Due to the advancements in 5 G technologies, high-definition, and the internet of things (IoT), the capacity demand of optical networks has been exponentially increased. Optical communication networks offer several metrics such as high transmission capacity, low transmission loss, better anti-interference, robustness, etc which offers new opportunities to the communication field. To satisfy the increasing demands of optical networks, effective network resource utilization become essential. So, it is needed to design proper planning tools with superior accuracy for quality of transmission (QoT) in optical networks. Recently, artificial intelligence (AI) techniques pose new opportunities for resolving these issues and machine learning (ML) algorithms offer better performance over the analytical approaches. With this motivation, this paper presents a novel AI based cognitive QoT prediction (AI-CQoT) model for optical communication networks. The proposed AI-CQoT model aims to predict the QoT for the quality of service (QoS) link setup using AI techniques with the transmission equation based synthetic data generation. The proposed model uses the Label weighting extreme learning machine (LW-ELM) model for the prediction process which includes a link and signal characteristics as input features. Besides, the LW-ELM model is trained by the use of transmission equations. For improving the predictive performance of the LW-ELM model, the parameters such as weight matrix W and penalty factor C are optimally tuned by the use of the shuffled shepherd optimization (SSO) algorithm. A detailed experimental validation is performed to highlight the improved performance of the AI-CQoT model and the results are investigated in terms of different performance measures.
查看更多>>摘要：The mathematical model for description of pulse propagation in optical fiber for the generalized anti-cubic nonlinearity with arbitrary refractive index is considered. The Cauchy problem for this partial differential equation cannot be solved by the inverse scattering transform and the analytical solutions of this mathematical model are found taking into account the traveling wave reduction. First integral of nonlinear ordinary differential equation is presented. Analytical solutions in the form of periodic and solitary waves are found using some transformations. Partial cases of the mathematical model for the generalized anti-cubic nonlinearity are studied.
查看更多>>摘要：In this paper, we present a complete method for determining the two surfaces of an aspheric singlet by numerical integration based on the classical Wassermann-Wolf equations (hereinafter WW). Although aplanatic optics is mainly treated in WW, we also show some other examples that can be determined by the WW. This indicates that surface shape determination by optimization software such as Zemax or CodeV is not necessary for some aspherical singlet designs, including the aplanatic case. A link to an executable Mathematica code for this purpose is also provided.
Hooda, AnjuKhatkar, S. P.Taxak, V. B.Devi, Sushma...
13页
查看更多>>摘要：Nanocrystalline BaY1_xErxZn(3)AlO(7) (x = 0.01-0.05) phosphors are derived via solution combus-tion synthesis. Williamson-Hall plot evaluated crystallite size (86.12 nm) and micro strain (0.00143) of the optimized sample. TEM study validates the fabricated particles size in nano-range. Under excitation upon near ultraviolet source (381 nm), emissive peaks are identified at 527 nm (H-2(11/2)-> I-4(15/2)) and 566 nm (S-4(3/2)-> I-4(15/2)). CIE color coordinates proved emanation in the yellowish-green section. The energy band gap, refractive index and CCT values for optimum nanosample are found to be 4.66 eV, 1.77 and 5416 K respectively. All results indicate that BaY1_xErxZn3AlO7 nanophosphors possess ample applications in WLEDs.
查看更多>>摘要：In this paper, we introduce new nonclassical states called two-mode squeezed vacuum states with superposition of photon-pair addition and subtraction operations (TMSVSs-SPPASOs) by adding and subtracting pairs of photons to a two-mode squeezed vacuum state (TMSVS). It is shown that the superposition operations of photon-pair added and subtracted can enhance the degree of entanglement of the TMSVSs-SPPASOs by using the linear entropy criterion. Besides, the EPR correlation and the EPR steering in the TMSVSs-SPPASOs can be improved compared with the original TMSVS. In particular, the manifestation of these features becomes more obvious in the small region of the squeezing parameter r in the TMSVSs-SPPASOs. By using the TMSVSs-SPPASOs as entanglement resources, the quantum teleportation process of a qubit-type single-mode state is studied in detail. Based on the average fidelity Fav, it indicates that the quantum teleportation process is ideally successful as Fav approaches the unit when r is high. More importantly, the average fidelity Fav can be enhanced by increasing the number of photon pairs added or subtracted. Finally, we propose experimental schemes for generating these states by using quantum optical devices.
查看更多>>摘要：Coupling between the active centers generated by localized states and the two-dimensional photonic crystals (2D-PCs) has been used to select model in the nano-laser and the optical interconnects on silicon chip. The photonic crystals have been investigated in the simulating calculation, and the physical model has been built in the manipulation of photon states. New quantum phenomena appear in the photonic crystals as well as in the atomic crystals. We have numerically studied on the band structure of 2D-PCs with different types of lattice and various shapes in the optical communication windows. The simulating calculation results show that the band gap of photon states can be effectively manipulated in 2D-PCs by using the competition between the quantum confinement effect and the lattice symmetry effect, in which the band gap width of the photon states will obviously increase by changing the lattice symmetry and by increasing the filling rate of the air hole to restrain photons in 2D-PCs on silicon. It is interesting to make a comparison between the transverse electric (TE) polarization and the transverse magnetic (TM) polarization, in which a wider band gap occurs in the TM mode. By adjusting the defect mode in 2D-PCs, the photon states can be localized into the second and third windows of optical communication for selecting modes and resonating on silicon chip.
查看更多>>摘要：Orbital angular momentum (OAM) is a degree of freedom independent of polarization and frequency of vortex beams. Therefore, the measurement of OAM has attracted great interest. In this paper, we propose a method to detect OAM beams utilizing far-field diffraction feature fringes caused by fork-shaped grating (FSG), which has characteristics of wide-range, high efficiency, and excellent extensibility for detection of high-order OAM beam. We give a detailed explanation of the concept and feature of FSG detection theoretically, and improve detection reliability of fringes by increasing the number of forks and setting appropriate offset. Experimentally, we achieve detection of OAM+50. Moreover, although only two OAMs were detected at the same time in our experiment, FSG can also be used in the detection of multi-OAM beams due to the excellent extensibility of this method. Our finding opens up a new method for the detection of high-order OAM and multi-OAM beams, which is of great significance to the application of FSG.
查看更多>>摘要：The present study offers two Al/Si multilayer-grating microstructures based on SiO2 substrate. The two microstructures exhibit narrowband absorption in infrared wavebands. Based on different positions of the grating ridge, the finite element method is used for simulation, and a single-band absorber and a dual-band absorber are obtained under TM polarization. Perfect absorption of 99.77% is achieved in single-band absorber. The dual-band absorbers also achieve efficient absorption of 95.44% and 96.26% at the points of 3712 nm and 6443 nm. The production tolerance of the absorber is also investigated and analyzed, and the two absorbers are found to have great application prospects. Narrowband absorbers are widely used in areas such as high sensitivity sensors.
查看更多>>摘要：In this study, DFT calculations carried out using Carbazole-based HTMs substituted with dimethoxy phenylamine units (DMPA) in positions 2,3,6,7 and 9 are coupled with the experimental results drawn from the literature. The most important challenge for us is to establish a link between the optoelectronic and structural properties of molecules and their performance as HTMs. In this work, we find that the important structural effect is generated by the pyridinic nucleus. The substituents linked to the nitrogen atom of carbazole do not contribute to HOMO or LUMO in most of the studied HTMs. Hence, apart from the illustrated performances, parameters as the contribution of such substituents to being attached to the perovskite, or to the cohesion of the HTM's molecules contributing to the perovskite stability all prove decisive. The 2,7 substitution favors more stabilization of LUMOs when compared to 3,6 substitution, which leads to a narrow gap for 2,7 homologous. This makes these 2,7-substituted molecules good candidates as light absorbent in Organic Solar cells. The differences in the solar cell performances using these HTMs is mostly linked to the effect of these groups on their intermolecular interactions on one hand, and on the interfacial contact between HTMs and perovskite on the other hand.
NSTL
Elsevier