Journal of Nonlinear Optical Physics & Materials

The rotation characteristics of the composition Laguerre–Gaussian (LG) beams during the propagation are numerically analyzed. A simple rotation angle measure method based on imaging technology is proposed and demonstrated. First, the global feature points of the composite vortex pattern is extracted by the 8-connected boundary tracking algorithm. Then, the position coordinates of each feature point are calculated by using the weighting method. The rotation angle of each feature point relative to the center point is calculated under the coordinate system. Finally, the relative rotation angles of the composite vortex pattern at different positions relative to the original position are obtained. The results show that the measurement error reaches 10${}^{-4}$ for composite beams with different sizes and beam waist, which is comparable to that of the theoretical value. The proposed method can be used to effectively and accurately measure the Gouy phase of the composite LG beams. We expect the proposed method will be benefit of the further research and application of Gouy phase.

A novel copper coordination polymer [Cu(Hssipa)(Hpao)(H₂O)]${}_n$ (1) based on 5-sulfoisophthalic acid monosodium salt (NaH₂ssipa) and 2-pyridinealdoxime (Hpao) has been synthesized by solvent evaporation under magnetic field condition. Compound 1 feathers a two-dimensional framework with ${(6^3)}_2$ topology, which is constructed by Hssipa${}^{2-}$ ligands linked with Cu ions via the carboxylate and sulfonate groups in monodentate and bidentate modes, respectively. The Hpao molecules act as terminal ligands, chelated with Cu ions. Compound 1 displays the luminescence, arising from ligand centered $\pi -{\pi }^{\ast }$ transitions. In addition, the second-harmonic-generation (SHG) measurement revealed that it has a SHG response, which is 1.9 times that of KH₂PO₄.

Long-period fiber grating is widely used as an optical component in photonics communication technology. The optical pulse propagation in grating has been studied mostly numerically and some number of studies carried out experimentally. The detailed analytical investigation has not been reported due to the complexity of the mathematical equations. Here, we have investigated analytically the effect of dispersion and nonlinearity on ultrafast optical pulse propagation in long-period fiber grating and derived the expression for transmitted optical pulses because the detailed analytical investigation has not been reported by any authors. The results of the study show how grating-induced overall dispersion and nonlinearity-induced self-phase modulation (SPM) modify the shape of the ultrashort optical pulses when it’s propagating through a length of the grating. The combined effects of dispersion and SPM on the optical pulse evaluation are also analyzed. From the plotted graphs it is investigated that the dispersion of the grating distorted the pulse shape whereas SPM shifts the pulse towards the higher time scale. It is also investigated that the distorted optical pulse due to dispersion is reshaped by the nonlinearity introduced in the medium due to the combined effect of dispersion and SPM. Optical pulse compression, optical limiting and pulse reshaping are also illustrated as a function of excitation intensity.

Pure single crystals of ammonium dihydrogen phosphate (ADP) and crystals containing 1, 3, and 5mol% of itaconic acid (ITA) were generated by the slow evaporation of an aqueous solution. With the help of powder X-ray diffraction and Fourier transform infrared spectroscopy, we were able to show that doping puts a lot of stress on crystals. According to the of Vickers microhardness results, the addition of ITA causes the ADP to have a greater degree of abrasiveness. The SHG efficiency of ITA-doped ADP is greater than that of pure ADP. The presence of dopant was established using the energy-dispersive spectroscopy. The $Z$-scan method was used to investigate the third-order nonlinear optical characteristics of ITA–ADP crystals formed by the slow evaporation method on a variety of planes. A He–Ne laser with a wavelength of 632.8nm was used to carry out the investigation. The nonlinear absorption coefficient, nonlinear refractive index, and third-order nonlinear susceptibility of the ITA–ADP crystals were also plotted in detail. The piezoelectric charge coefficient of pure ADP is lower than that of the ITA-doped ADP. Analysis of the electro-optic investigation reveals lesser half-wave voltage of doped ADP.

This paper reports simplified but accurate form of analytical expressions concerning the estimation of Petermann I and II spot sizes. Typical examples of dispersion-managed fibers for fundamental mode guidance with suitable $V$ numbers have been considered in our investigation. We employ the mathematical formulation in the estimation of Petermann spot sizes for the said fibers under the absence and existence of Kerr-type nonlinearity. Iteration technique is utilized in our investigation. Our predicted outcomes show excellent agreement with the precise numerical results found by complicated finite element method both in the absence and presence of Kerr-kind nonlinearity.

This paper presents an analytical model of the origin of nonlinear crosstalk induced by the XPM-SMZI (Cross-Phase Modulation-Symmetric Mach–Zehnder Interferometric) phenomenon occurring in the TWSOA (Traveling Wave Semiconductor Optical Amplifier). We analyze the variation of nonlinear crosstalk with increasing logic levels and length of the input bit sequence. The investigation shows that alteration in high and low logic of bit sequence engenders changes in cross-phase modulation occurring in TWSOA and hence brings nonlinear crosstalk into the picture. The performance is evaluated on 4×4 switching interconnect with a TWSOA cavity length of 500$\mu$m, a width of 3$\mu$m, and a height of 0.8nm with 0.15A injection current in SMZI configuration operating at 10Gbps. The performance of the switch is also tested by comparing various combinations of bit logic inputs. The degradation is observed in the quality of service with an increase in the number of ‘1’s in bit sequence. The Extinction Ratio (ER) also deteriorates when a logic ‘1’s appears at consecutive places. This impairment in ER can be controlled by bias conditions of TWSOA. The promising crosstalk of $-30$dB has been achieved and is further validated by comparing with previously reported techniques.

The Perturbed Gerdjikov–Ivanov Equation (PGIE) describes optical solitons in nonlinear fiber optics and photonic crystal fibers. It was currently studied in the literature. Here, we consider a new complex field equation, the PGIE with fourth-order dispersion. The exact solutions of the aforementioned equation are obtained by implementing the unified method. These solutions are evaluated numerically and they are shown in graphs. Our objectives, here, are to inspect the onset of self- steepening and self-phase modulation and investigate the structures of solitons produced. It is found that these phenomena are launched for high values of the relevant coefficients, and they may be overlapped. Multiple solitons shapes are observed; M-shaped solitons, rhombus shapes, solitons with tunneling, 2D-lumps vector, and solitons- cascade. Further, the analysis of modulation instability (MI) and global bifurcation are carried out. It is established that the MI triggers when the coefficient of Raman scattering exceeds a critical value. It is worth mentioning that two kinds of bifurcations can be studied, namely local and global bifurcations. Here, we are concerned with studying global bifurcation. This is based on constructing the phase portrait via Hamiltonian function.

In this paper, the effect of the process parameters such as laser power, shielding gas flow and scanning velocity on the actual laser power reaching the surface and thermal efficiency is investigated. For this purpose, the response surface methodology was used to investigate the effect of the process parameters at three levels. In order to measure the data from a 316L stainless steel, four k-type thermocouples are installed in different positions relative to the motion of the laser beam. The actual power was calculated by reverse analysis using the simulated annealing technique and the temperature history was measured by the thermocouples. The thermal model used is an optimized Rosenthal model, which is considered variable with temperature. The results show that for all thermocouples, the highest values of actual power that reached the surface were obtained at laser power of 200W, scanning velocity of 2mm/s and shielding gas flow of 30Lit/min. In addition, by increasing the laser power from 100 to 200W, the thermal efficiency decreases by about 4% to 12%. The thermal efficiency also decreases by about 8%, when the scanning velocity increased from 1 to 3mm/s. Moreover, the increase of the shielding gas flow from 25 to 35Lit/min initially improved the thermal efficiency and then decreased it. The models obtained from the analysis of variance in the heating cycle are in good agreement with the experimental results, but in the cooling cycle, the accuracy of this model decreases.

The paper discusses the synthesis and characterization of Cd${}_{1-x}$Mn${}_x$O nanoparticles using the precipitation method for potential optoelectronic applications. X-ray diffraction analysis revealed a cubic polycrystalline structure, with a decrease in crystallite size as Mn concentration increased. UV–Vis spectroscopy data showed changes in the band gap with varying Mn concentrations, with $E_g^{\mathrm{\text{opt.}}}$ decreasing from 2.523eV to 2.304eV as Mn content increased up to 3%. However, with further increases in Mn content, $E_g^{\mathrm{\text{opt.}}}$ increased to 2.332eV. The study also estimated various optical properties, providing valuable insights into the optical behavior of Cd${}_{1-x}$Mn${}_x$O nanoparticles. In addition to the aforementioned characterizations, the paper explores the influence of Mn content on dispersion parameters using Wemple Di-Domenico models. The dispersion energy ($E_d$) was found to increase from 13.502eV to 14.170eV, while the single oscillator energy ($E_o$) decreased from 3.483eV to 3.142eV with increasing Mn content. This suggests that the incorporation of Mn into CdO alters its optical properties significantly. Furthermore, the study calculated non-linear optical coefficients, such as the third-order non-linear susceptibility ($\chi$(3)) and non-linear refractive index ($n_2$), for CdO nanostructured powder doped with Mn. These findings indicate the potential suitability of Cd${}_{1-x}$Mn${}_x$O nanoparticles for applications in the fields of optics and electronic devices, highlighting their potential for use in advanced technologies requiring tailored optical properties and nonlinear behavior.