Optik最新文献

A green, plant extract-mediated synthesis technique utilizing the Aloe vera stem extract with Zinc acetate (Zn(CH₃CO₂)₂·2H₂O), and Tungsten chloride (WCl₂) salt has been employed to grow Zinc Oxide (ZnO) and tungsten doped ZnO (W-ZnO) nanoparticles (NPs). The formation of NPs was confirmed by FESEM with EDX and TEM analysis. The synthesized NPs have been employed for fabricating ZnO and W-ZnO thin films and the electro-optical properties of the films have also been investigated in detail. The thin films have obtained via spin coating and followed by annealing at 350 °C for 3 h in an ambiance atmosphere. The films showed smooth surfaces with a bandgap of 3.20 and 3.25 eV for ZnO and W-ZnO respectively. Finally, a novel structure inverted perovskite solar cells (PSCs) has been numerically analyzed utilizing the films as an electron transporting layer (ETL) for realizing the device performance. The highest PCE of the device for synthesized ZnO and W-ZnO has been found to be 21.16 % and 23.61 %, respectively. All of the findings show that the W-ZnO film is more suitable for the fabrication of PSCs than the ZnO film. In a nutshell, the synthesis of W-ZnO NPs employing green and eco-friendly methods, mediated by Aloe vera extract as the reducing agent, offers in this study a novel approach to enhancing solar cell efficiency with the simple spin coating fabrication technique.

This letter presents a dual-frequency terahertz amplitude modulator based on a cross-shaped structure and U-shaped metal patches. Its structural unit is a typical metal-substrate structure. The top metal consists of a cross-shaped structure and U-shaped metal patches, and the bottom substrate layer is made of quartz. Amplitude modulation is achieved by adjusting the temperature of the vanadium dioxide (VO₂) patches. The modulation depth can be approximately 75 %. The mechanism of the resonance frequency is explained by the equivalent circuit model. The proposed structure shows good amplitude modulation capability at different incidence and azimuth angles by changing the location of the VO₂ patches. The dual-frequency terahertz amplitude modulator can be used in terahertz communication, imaging, etc.

Optical properties of a synthetic dye cresol red (CR) were investigated at its absorption band maxima (${\lambda }_{\max }$) using double beam scanning UV/VIS spectrophotometer for the sample solutions having initial optimized dye-concentration. Urbach Edge method was utilized for the investigations of absorption edge ($A_E=$ 2.35 eV) while Mott and Davis model was utilized for the investigations of band gap energy for direct ($E_{g,\mathrm{direct}}=$ 2.45 eV) and indirect ($E_{g,\mathrm{indirect}}=$ 2.23 eV) allowed transitions. The spectrophotometric-evaluations assisted most-sensitive working pH of sample solutions was optimized for a long spectrum of pH values from 1 to 12 for further investigations. Some spectrophotometric and comercial parameters e.g., molar extinction coefficient $\left(\epsilon \right)$, stability, reproducibility and fading were figured out. The response efficacy was also observed to enhanc the sensitivity and stability of the CR solutions by incorporating a selected amount (by %vol) of a polar additive ethanol. The invariant aborbance related isosbestic wavelength for both acidic and alkaline samples remained unaffected from pH and firmly stood at 475 nm. The improved and reasonable pH values were found to be pH 4 and pH 9 and hence were opted for CR solutions and may further be applicable to the radiation-induced degradation phenomenon based on radiolytic bleaching.

This research involves stress-strain analysis in poly(methyl methacrylate) (PMMA) octagonal shape compressed by hydraulic system. The observation of uniaxially stressed samples was carried out using reflection photoelasticity technique. The results of fringe order number and principal stress angle were used to determine stress and strain distribution in the samples by shear difference method. It was found that high stress-strain region was close to the contact point where compressive force was applied but it was zero at the edge of the samples. The area of high strain region increased as the magnitude of force was increased but it decreased as the dimension of octagonal shape was increased.

Fringe pattern normalization is an important pre-processing operation in optical fringe analysis, and is usually required as the initial step for several phase retrieval methods. However, noise and rapid amplitude fluctuations in the fringe pattern pose significant challenges for fringe pattern normalization. In this paper, we propose a robust approach for fringe normalization using conditional Generative Adversarial Network, which works on the principle of image-to-image translation with conditioning on input images. The performance of the proposed method under different noise conditions and amplitude variations is demonstrated using numerical simulations. Further, the practical applicability of the proposed method is also tested with experimental data obtained in digital holographic interferometry.

Suppression of the cross-talk between neighboring photonic components has been considered one of the most efficient methods for increasing the packing density of photonic integrated circuits. In this study, an effective cross-talk reduction approach is developed for plasmonic waveguides. Firstly, the mode characteristics of the waveguide are investigated, and then two silicon strips are placed beside the two adjacent waveguides. The mechanism of the cross-talk suppression method highly relies on the evanescent waves. The designed strips in this study manipulate the wave vectors of surface plasmon polaritons. The tangential component of the wave vector is conserved along the interface, while the perpendicular component in the surroundings can be equal to zero or imaginary, leading to evanescent waves. Placing the strips increases the perpendicular component of the wave vector in the surroundings, resulting in less cross-talk. So, the coupling length of the waveguide with the strips at the wavelength of 10 μm increases up to 345 μm which is 25 times longer than that in its non-strip counterpart. Also, the figure-of-merit and loss of the designed structure are up to 1000 and 0.13 dB/μm at a chemical potential of 0.8 eV and a wavelength of 10 μm, respectively. So, high figure-of-merit and low loss along with long coupling length are the interesting features of the designed plasmonic waveguide which propose promising structures with high performance in the near-infrared.

The current research introduces a comparison study of the utilization of artificial neural networks (ANN) and genetic programming (GP) for predicting the optical behavior of different materials. The experimental data for a variety of materials, including semiconductors, insulators, oxides, and halides are extracted and utilized in ANN and GP as inputs. Simulation and prediction processes are carried out based on ANN and GP techniques. The most important aim presented in the current research is to obtain two equations of n as a function of E_g by the two based on ANN and GP models. The first numerical equation is obtained based on the ANN model exhibiting mean squared error (MSE) does not exceed 1$0^{-1}$. The second nonlinear equation is obtained based on the GP model with an acceptable fitness value. The estimated results based on the proposed approaches ANN and GP presented a great match with their targets. It demonstrated that the trained results including simulated and predicted results based on ANN and GP introduce excellent fitting compared with alike results obtained based on the conventional theoretical techniques. The mean absolute percentage error values prove that the ANN model is significantly more accurate than the GP model. Since lower error values suggest better prediction, hence it is clear that ANN performed better than GP. The equation derived by the ANN model is utilized to predict the refractive index for binary and ternary compounds. The values of the refractive index have been predicted for materials for which measurements have been made practically as a test step to ensure the accuracy of the results obtained through the deduced mathematical equations. Then, the application of these equations was generalized to materials that were not measured experimentally. A detailed discussion of the modeling results is introduced and proved that ANN and GP models are effective and successful tools for predicting the refractive index for different types of materials.

The design and investigation of an electro-absorption modulator (EAM) based on a T-shaped plasmonic material is presented in this paper. Utilizing the finite element method (FEM), the properties of indium tin oxide (ITO) have been explored in terms of permittivity and refractive index. At an application wavelength of $1.55\mu m$, the ITO-based EAM’s extinction ratio (ER), insertion loss (IL), and figure of merit (FOM) have been calculated and observed to be 8.68 dB/$\mu m$, 0.028 dB/$\mu m$, and 310, respectively. Additionally, the EAM, utilizing vanadium dioxide (VO₂) as the plasmonic material has shown a shift in the device’s performance matrices. Furthermore, the performance of the devices have been investigated based on four different dielectric materials such as hafnium dioxide (HfO₂), silicon nitride (Si₃N₄), boron nitride (hBN), and silicon dioxide (SiO₂). When compared to contemporary devices, the designed plasmonic material-based EAMs have shown better performance. The modulators under investigation have the potential to become a crucial components of future photonic circuits.