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Investigation on the crack fracture mode and edge quality in laser dicing of glass-anisotropic silicon double-layer wafer
摘要： This work puts forward numerical and experimental investigations on laser dicing of glass-anisotropic single-crystal silicon double-layer wafer using laser induced thermal-crack propagation (LITP). A semiconductor continuous wave laser working at the defocusing mode serves as volumetric heat source for glass layer while as surface heat source for silicon layer. Based on the classical fracture theory, a static seam-type crack is introduced under the circumstance of ABAQUS to simulate the crack fracture modes in glass layer as well as silicon layer with crystal planes of (100), (110) and (111) during laser dicing in different dicing directions. In the experiments, processing parameters are kept the same as the simulations and typical dicing directions obtained from simulations are also used. The surface morphologies of crack edges are measured by the optical microscope and surface profiler. Through the comparison of numerical and experimental results it is discovered that for the specific substrate, the evolution of crack edge qualities in different dicing directions and different layers can be interpreted based on the corresponding stress distribution and stress intensity factor (SIF) ratio explicitly. And most important of all, the anisotropy of silicon layer has significant influence on the fracture mode and edge quality of crack in both layers.
关键词： Crack fracture mode,Laser induced thermal-crack propagation,Glass-anisotropic single-crystal silicon double-layer wafer,Crack edge quality,Static seam-type crack
更新于2025-11-21 11:24:58
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Soliton slow light for closed loop quantum systems
摘要： This paper describes the dynamics of solitonic pulse propagation in a closed loop quantum system comprised of five atomic energy levels. Although the propagation of an intense probe pulse suffers losses and broadening in linear regime, there exist specific conditions where the probe pulse is found to become robust during its propagation. We attribute this regime to the formation of an optical soliton with a slow group velocity because of the balance between the dispersion and Kerr optical nonlinearity. Results obtained are based on the theoretical model using the coupled Maxwell-Bloch equations for the nonlinear propagation.
关键词： Optical solitons,Kerr nonlinearity,Nonlinear pulse propagation,Closed-loop quantum system
更新于2025-09-23 15:23:52
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Propagation properties of Airy Ince–Gaussian wave packets in gradient-index media
摘要： We study localized Airy Ince–Gaussian (AiIG) wave packets in gradient-index (GRIN) media by solving the spatiotemporal evolution equation analytically. The generation and manipulation of AiIG wave packets in GRIN media are affected by the direction of the self-accelerating, elliptical, refractive index distribution parameter, initial velocity and mode number. In addition, energy flow, angular momentum and radiation force, which change periodically, are also thoroughly discussed. The Airy helical Ince–Gaussian wave packets exhibit multiple vortices and carry orbital angular momentum, which have potential applications in optical tweezers and optical communications.
关键词： vortex,Airy Ince–Gaussian wave packets,propagation
更新于2025-09-23 15:23:52
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Wave Propagation of Porous Nanoshells
摘要： This study aims at investigating the wave propagation of porous nanoshells. The Bi-Helmholtz non-local strain gradient theory is employed in conjunction with a higher-order shear deformation shell theory, in order to include the size-dependent effects. The nanoshells are made of a porous functionally graded material (P-FGM), whose properties vary continuously along the thickness direction. A variational approach is here applied to handle the governing equations of the problem, which are solved analytically to compute the wave frequencies and phase velocities as function of the wave numbers. The sensitivity of the wave response is analyzed for a varying porosity volume fraction, material properties, non-local parameters, strain gradient length scales, temperature, humidity, and wave numbers. Based on the results, it is verified that the size-dependence of the response is almost the same to the one of plates, beams and tubes.
关键词： doubly-curved nanoshell,wave propagation,higher-order shear deformation shell theory,porous materials,generalized non-local strain gradient theory
更新于2025-09-23 15:23:52
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Contrast of optical activity and rogue wave propagation in chiral materials
摘要： We report the contrast of optical activity and properties of nonparaxial optical rogue waves for the higher-order nonparaxial chiral nonlinear Schr?dinger (NLS) equation. The latter describes the propagation of ultrashort optical pulses in chiral optical fibers. Both first- and second-order rogue wave solutions are investigated analytically by the modified Darboux transformation (MDT) and numerically by one pseudo-spectral method. The interplay of chiral materials on rogue wave propagation is elucidated, and the results can be applied on optical communication and in others physical systems.
关键词： Chirality and optical activity,Chiral optical fibers,Rogue wave propagation,Chiral materials
更新于2025-09-23 15:23:52
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Methodology for diagnosing crack patterns in masonry structures using photogrammetry and distinct element modeling
摘要： Understanding the causes of damages on existing structures can augment preservation, renovation, and rehabilitation efforts. The aim of this work is to outline a method for diagnosing the most probable causes of cracks on existing structures using a combination of photogrammetry and distinct element modeling (DEM). Five experimental, masonry walls were constructed and cracked; the state of the wall before and after cracking was recorded using photogrammetry. Using distinct element modeling, each test wall was subjected to a variety of loading conditions including the same load case which was used to crack the wall during experimental testing. The crack patterns in the simulations were compared to the experimental crack patterns using a combined qualitative and quantitative method. The simulation which most closely reflected the existing damage patterns was selected as the most probable cause of the damages. For each of the test walls, the real simulated load had the closest fractional distance to the existing damage patterns captured by photogrammetry. This method was then applied to diagnose possible causes of cracking on a foundation wall in the Baptistery of San Giovani in Florence, Italy.
关键词： Distinct element modeling,Masonry,Building pathology,Diagnosis,Crack propagation,Photogrammetry
更新于2025-09-23 15:23:52
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Ultra high transmission capacity based on optical first order soliton propagation systems
摘要： This study presents the first order optical soliton propagation systems for ultra-high transmission distance that reaches up to 20,000 Km with transmission data rates of 80 Gb/s and its corresponding maximum Q-factor and Soliton peak power. The simulation has been performed for the distance up to 20000 Km at the operating wavelength of 1300 and 1550 nm.
关键词： High data rates,Soliton propagation systems,First order soliton
更新于2025-09-23 15:23:52
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Control of the creation of bottle-hollow beam by polarization shaping
摘要： We propose a method for generating bottle-hollow (BH) beams by tailoring the polarization state of the incident field in a tightly focused system. An optical BH field can be generated in the vicinity of the focus by tailoring azimuthal and radial polarization indices of the incident field. Calculations show that the length and diameter are mainly affected by the radial polarization index. While for the azimuthal index, it affects the width of the hollow greatly. As a result, an all-optical controlled tunable BH beam is achieved. The generated BH beam may find application in optical tweezers.
关键词： Diffractive optics,Singular optics.,Polarization,Propagation
更新于2025-09-23 15:23:52
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Effects of the microstructure and density profiles on wave propagation across an interface with material properties
摘要： The characterization of the interphase condition between two materials is current in mechanics. In general, its modeling is achieved by considering an interface with only purely elastic properties. In this paper, following previous works, also inertial interface properties are taken into account. For sufficiently low-frequency regime, we investigate two density profiles (affine and quadratic), for the interphase. Moreover, the interface and the interphase are placed between two solids with different characteristics. The first one is non-dispersive, while for the second one three cases are considered: (a) solid without microstructure, i.e., a Cauchy continuum, (b) solid with microstructure characterized by normal dispersion, i.e., a strain gradient continuum, and (c) by anomalous dispersion. The reflection coefficients are plotted for each case. These results are evaluated with respect to a benchmark finite elements simulation of the finite heterogeneous interphase, and the error is discussed. It is shown that the effects of microstructure can be appreciated at higher frequencies and that the proposed model results to be accurate.
关键词： Strain gradient,Reflection coefficient,Interface,Interphase,Density profiles,Wave propagation
更新于2025-09-23 15:23:52
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Hyperspectral Image Classification Based on Belief Propagation with Multi-features and Small Sample Learning
摘要： In order to solve the "massive information but low accuracy" problem of hyperspectral image (HSI) classification, a novel HSI classification method MFSSL-BPMRF based on belief propagation (BP) Markov random field (MRF) using multi-features and small sample learning (MFSSL) is proposed in this paper. Firstly, an extended morphological multi-attributes profiles algorithm is used to extract spatial information of HSI, and a spatial–spectral multi-features fusion model is established to improve classification results. Then, BPMRF is used for image segmentation and classification because of its superiority in the spatial–spectral combination classification. MRF can describe the spatial distribution features of ground objects based on neighborhood model, and the spectral information of pixels can be integrated into the calculation of conditional probability. BP is used to learn the marginal probability distributions from the multi-features fusion information. Finally, the small sample training set is selected to enhance the computational efficiency. In the experiments of several hyperspectral images, the proposed method provides higher classification accuracy than other methods, and it is efficient for the classification with limited labeled training samples.
关键词： Features fusion,Belief propagation,Hyperspectral image,Classification
更新于2025-09-23 15:23:52