Alngar, Mohamed E. M.Shohib, Reham M. A.Gepreel, Khaled A.Zayed, Elsayed M. E....
7页
查看更多>>摘要：In this paper, we deduce the soliton solutions of the Kundu-Eckhaus equation in birefringent fibers. The addendum to Kudryashov's method and the modified Kudryashov's method have been used. The combo bright-singular soliton, dark soliton, bright soliton and the singular soliton solutions are existed under constraint conditions.
查看更多>>摘要：This paper presents a study of optical solitons for the fractional complex Ginzburg-Landau equation (CGLE) with Kerr law nonlinearity using different fractional differential operators. The soliton solutions of the equation have been investigated with conformable, beta and M-truncated derivatives. A Jacobi elliptic function finder technique, namely, new extended phi(6)-model expansion method has been utilized for the construction of the solutions. A variety of soliton solutions to the complex Ginzburg-Landau equation have been obtained. The comparison of some of the retrieved solutions has also been graphically illustrated using the three fractional differential operators.
查看更多>>摘要：As a new two-dimensional MXene material, Nb2AlC has a wide range of applications due to its superior optical, physical, and chemical properties. In this paper, we prepared a Nb2AlC-based saturable absorber (SA) and demonstrated its nonlinear absorption performances by a 2-mu m scope nanosecond laser. Based on Nb2AlC SA, an 1.62-W average output power and a 850-ns pulse duration at 135 kHz were obtained from a passively Q-switched Tm:YAP (PQS) laser with a 10.34-W pump power, and a 12.00-mu J pulse energy was achieved in the experiment, corresponding to a central output wavelength of 1987.2 nm and an optical-optical conversion efficiency of 13.5%. In addition, beam quality factors less than 1.10 in x-axis direction and y-axis direction were achieved from the PQS Tm:YAP laser.
查看更多>>摘要：A cascaded dual-core photonic crystal fiber (DC-PCF) refractive index sensor is proposed. The sensor is composed by cascading a single-mode fiber with a DC-PCF, thus realizing the vernier effect. The central air hole of the DC-PCF is filled with different refractive indices. The refractive index sensitivity is investigated using the full vector finite element method (FEM). The simulation results show that the cascade structure of the DC-PCF with three different air hole diameter parameters has high sensitivity up to-303376 nm/RIU in the refractive index range of 1.362-1.366, and the highest sensitivity of the cascade corresponds to a resolution of 3.30 x 10(-7). The sensitivity is increased by 37 times compared to the DC-PCF without vernier effect.By replacing the central air hole material, the sensor can be used for temperature sensing, magnetic field sensing and water quality analysis.
查看更多>>摘要：Digital Holography (DH) is a popular and practical technology for recording the complex-valued information of the object field. However, speckle, caused by the coherent light, greatly reduces the quality of the reconstructed image. In this paper, a speckle-suppression algorithm called Gauss speckle elimination mask (GSEM) that only needs a single-shot DH is proposed. This method utilizes the Gauss window function to extract the sub-holograms. Besides, the gray value compensation is proposed in this method for restoring the grayscale distribution. All sub -holograms are operated by the gray value compensation, then a new stack of sub-reconstructed images is acquired. The output compounded by this stack of sub-reconstructed images avoids the additional noise caused by the ringing effect. It could be shown in this paper that this method has a better performance in speckle-suppression while maintaining the image contrast.
查看更多>>摘要：The multi-core silicon-rich nitride photonic integrated waveguide is presented here to numerically model the spanning of supercontinuum generation in the mid-IR region beyond the 4 mu m wavelength range by engineering the dispersion profile such that maximum phase-matching can be achieved. Tunable dispersive wave generation has been observed in a long mid-IR region up to 5.2 mu m wavelength by the variation of gap spacing between the cores. This unique geometry enables a higher phase matching from 1.2 mu m to 2.6 mu m wavelength range resulting in the flat dispersion profile in the near-IR region by coupling the fundamental mode in narrow waveguide core to the higher-order mode in wide waveguide core that gives rise to anomalous GVD which plays an essential role in compensating chromatic dispersion in the mid-IR region.
查看更多>>摘要：Electron beam welding (EBW) is one of the most extensively utilized high energy-based joining processes having many advantages, namely high penetration, improved weld quality etc. But the electron beam used for joining of materials is subjected to electron-repulsion-induced space charge effect (SCE). This SCE has shown significant variation in the weld-geometries, cooling rate and microstructural features during EBW process for a fixed value of heat input, thereby limiting the effective applicability of the joining process. The present study provides mathematical modeling to study the influence of this SCE on various electron beam attributes. This includes the estimation of electron velocity and penetration, their kinetic energies, de Broglie's wavelength, current and charge densities, number of electrons, gap between the electrons and the Coulomb repulsion force between two electrons. Moreover, the SCE-induced beam divergence is presented through SIMION simulations. The modeling results are validated with the experimental observations.
Shackeerali, M.Ali, A. K. ShafeequeUthayakumar, A.
9页
查看更多>>摘要：In this article, we present a systematic investigation of modulation instability (MI) in negative index materials (NIMs) with higher-order dispersion and nonlinearity. We adopt the method of linear stability analysis and obtain an expression for the instability gain. Special attention is paid to studying the effect of fourth-order dispersion, quintic nonlinearity, first-order nonlinear dispersion, and second-order nonlinear dispersion on the instability gain. It is found that the fourth-order dispersion forms new instability regions and gives new ways to generate solitons or ultrashort pulse trains. Our study also shows that in the presence of higher-order dispersion a switching of the sign of cubic nonlinearity can generate two distinct MI regions. This result may provide a better way to generate different frequency ultra-short pulses as a result of switching of the sign of cubic nonlinearity by tuning the parameters of constituent elements of the metamaterials. Further, we observed that the cooperating cubic and quintic nonlinearities widen the MI by enhancing maximum gain and bandwidth, on the other hand, the competing cubic and quintic nonlinearities suppress the MI considerably.
Zayed, Elsayed M. E.Alngar, Mohamed E. M.Gepreel, Khaled A.
16页
查看更多>>摘要：The main goal of this article is to investigate the optical soliton solutions for the cubic- quartic (CQ) twin-core couplers and multiple-core couplers having optical metamaterials with parabolic non-local law nonlinearity and nonlinear perturbation terms. The couplings with nearest neighbors and with all neighbors are discussed. The unified Riccati equation expansion approach and the addendum to Kudryashov's approach are applied. Straddled, combo-bright singular, dark, bright, singular solitons solutions as long as periodic and rational solutions are found.
Eldidamony, Hanaa A.Zaghrout, Afaf S.Ali, Youssra S.Arnous, Ahmed H....
23页
查看更多>>摘要：In this article, highly dispersive optical solitons and other solutions in birefringent fibers are reported with quadratic-cubic law and polynomial law of refractive index. The improved modified extended tanh-function method is applied to derive soliton solutions and other solutions for the proposed model. We extract the solitons in the form of bright solitons, dark solitons, bright-dark combo solitons and singular solitons. Also, rational solutions, exponential solutions, hyperbolic solutions , periodic solutions, singular periodic solutions, Jacobi elliptic periodic type solutions and Weierstrass elliptic doubly periodic type solutions are presented. The existence criteria of the solitons are also presented. Moreover, for the physical illustration, some of the obtained solutions are represented graphically.
NSTL
Elsevier