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Interior booming noise during acceleration has been one of the most significant NVH problems for minivans. However, the generation mechanism of the interior booming noise remains unclear, so the access to reduce the booming noise is blocked. To solve the booming noise problem, a Source-Path-Receiver-Model-based approach is established to study the generation mechanism of the booming noise. Based on the generation mechanism, several modifications are proposed to reduce the minivan booming noise. In the established approach, the transfer path of the booming noise energy is figured out by the vehicle body and cavity experimental TPA, rear suspension dynamic analysis, and drivetrain torsional vibration analysis. Meanwhile, the vibroacoustic energy in the transfer processes is analyzed quantitatively. The identified generation mechanism is validated by the comparison of the test results of minivan interior noise and the simulation results from the established approach. During the minivan acceleration, the 5th torsional vibration mode (50.5 Hz) of the driveline is excited by the engine torsional vibration around 1500 r/min. Then, the driveline torsional resonance energy is transferred to the body and cavity through the rear suspension and finally leads to the interior booming noise. Based on the validated mechanism, several modifications are proposed to reduce the frequency response function of the driveline, the rear suspension, and the vehicle body around 50 Hz. With these modifications applied to the minivan, it is shown in the experimental results that the interior booming noise is reduced around 1500 r/min engine speed during acceleration. The mechanism study provides effective assistance with minivan interior booming noise reduction and the study approach also could be extended to explore the mechanism of other complex interior noise problems in automobiles. [ABSTRACT FROM AUTHOR]

Highlights • The optical force on a charged sphere by a vector Bessel beam is investigated in the framework of GLMT. • The emergence of a pulling force and its dependence on α 0 , order, polarization, and ka are discussed. • The ratios of axial RPCS for charged and neutral spheres are computed to investigate the effect of surface charge. • The optical forces on a relatively small sphere (a = 10 nm) are computed, and the effects of α 0 , order, polarization, and ka are discussed. Abstract Optical tractor beams can reel in an object towards the source, and are becoming a topic of significant worldwide research. Previous works considered the axial and transverse radiation pressure cross-sections (RPCSs) of optical tractor Bessel polarized beams on a dielectric sphere. However, most particles are charged, and it is important to investigate the tractor beam effect on charged particles. The aim of this work is therefore directed toward this goal, where the axial and transverse RPCSs for a charged sphere illuminated by a vector Bessel beam are computed in the framework of generalized Lorenz-Mie theory (GLMT). Numerical computations of the RPCSs are performed, with emphasis on the emergence of a negative pulling force and its dependence on the half-cone angle α 0 , the order l , and the polarization. A higher-order (l ≠ 0) Bessel beam possesses a hollow core and is of vortex nature, while the fundamental mode (l = 0) is of non-vortex type and has a bright maximum intensity at the center of the beam. In our calculation, both l = 0 and l = 1 are considered. The axial PRCSs versus ka and α 0 are first calculated, and the negative axial forces can arise. Moreover, the axial and transverse RPCSs in the plane perpendicular to the beam axis are computed. However, numerical results show that the RPCSs are same to that for a neutral particle. To explain this, the ratios of axial RPCSs for charged and neutral spheres are investigated taking ka as a parameter. The results show that charges only affect the RPCSs for small particles. Finally, the RPCSs for a charged sphere of relatively small are considered. The charge can affect the magnitude of the RPCSs, however, it does not affect the direction of axial optical forces. These results are of great importance in the development of novel optical tweezers and tractor beams. [ABSTRACT FROM AUTHOR]

The interaction of a vector Bessel vortex beam (VBVB) with a charged sphere is investigated using generalized Lorenz–Mie theory (GLMT). The charges carried by the sphere are expressed by the surface conductivity σ s . The incident VBVBs are expanded using a series of beam shape coefficients (BSCs), whose analytical expressions are derived using the angular spectrum decomposition method (ASDM). The expanded coefficients of the scattered fields are calculated by considering the boundary conditions on the surface of the sphere, which are different from that for the case of neutral sphere. The effects of the carried charges on the scattering, absorption, and extinction coefficients are considered, with particular emphasis on the effect of the order, polarization, and half-cone angle of the beams. Various polarizations including linear, circular, radial, azimuthal, and mixed polarizations are considered. Numerical results show that the scattering, extinction, and absorption efficiencies are very sensitive to the beam parameters including polarization, half-cone angle, and order. Thus in practice, the scattering, extinction, and absorption caused by charged particles can be enhanced or reduced by choosing proper beam parameters according to practical demand. Such results have many potential applications. For instance, it is of help to improve the quality of wireless communication by reducing the attenuation caused by charged particles. It can also improve the precision for particle sizing using phase Doppler anemometry by enhancing the scattering of charged spheres. [ABSTRACT FROM AUTHOR]

The optical spin torque (OST) induced by vector Bessel (vortex) beams can cause a particle to rotate around its center of mass. Previous works have considered the OST on a Rayleigh absorptive dielectric sphere by a vector Bessel (vortex) beam, however, it is of some importance to analyze the OST components for a sphere of arbitrary size . In this work, the generalized Lorenz-Mie theory (GLMT) is used to compute the OST induced by vector Bessel (vortex) beams on an absorptive dielectric sphere of arbitrary size, with particular emphasis on the beam order, the polarization of the plane wave component forming the beam, and the half-cone angle. The OST is expressed as the integration of the moment of the time-averaged Maxwell stress tensor, and the beam shape coefficients (BSCs) are calculated using the angular spectrum decomposition method (ASDM). Using this theory, the OST exerted on the light-absorptive dielectric sphere in the Rayleigh, Mie or the geometrical optics regimes can be considered. The axial and transverse OSTs are numerically calculated with particular emphasis on the sign reversal of the axial OST and the vortex-like character of the transverse OST, and the effects of polarization, beam order, and half-cone angle are discussed in detail. Numerical results show that by choosing an appropriate polarization, order and half-cone angle, the sign of the axial OST can be reversed, meaning that the sphere would spin in opposite handedness of the angular momentum carried by the incident beam. The vortex-like structure of the total transverse OSTs can be observed for all cases. When the sphere moves radially away from the beam axis, it may rotate around its center of mass in either the counter-clockwise or the clockwise direction. Conditions are also predicted where the absorptive sphere experiences no spinning. Potential applications in particle manipulation and rotation in optical tweezers and tractor beams would benefit from the results. [ABSTRACT FROM AUTHOR]

The interaction of an axicon-generated vector Bessel beam (AGVBB) with a homogeneous sphere is investigated in the framework of generalized Lorenz-Mie theory (GLMT). An analytical expression of beam shape coefficients (BSCs) is derived using angular spectrum decomposition method (ASDM), and the scattering coefficients are expanded using Debye series (DSE) in order to isolate the contribution of single scattering process. The internal and near-surface electric fields are numerically analyzed, and the effect of beam location, polarization, order of beam, half-cone angle, and scattering process (namely Debye mode p ) are mainly discussed. Numerical results show that a curve formed by extreme peaks can be observed, and the electric fields can be locally enhanced after the interaction of AGVBBs with the particle. Internal and near-surface fields, especially its local enhancement, are very sensitive to the beam parameters, including polarization, order, half-cone angle, etc. The internal fields can also be enhanced by various scattering process (or Debye mode p ). Such results have important applications in various fields, including particle sizing, optical tweezers, etc. [ABSTRACT FROM AUTHOR]

The optical torque exerted on an absorptive megneto-dielectric sphere by an axicon-generated vector Bessel (vortex) beam with selected polarizations is investigated in the framework of the dipole approximation. The total optical torque is expressed as the sum of orbital and spin torques. The axial orbital torque component is calculated from the z -component of the cross-product of the vector position r and the optical force exerted on the sphere F . Depending on the beam characteristics (such as the half-cone angle and polarization type) and the physical properties of the sphere, it is shown here that the axial orbital torque vanishes before reversing sign, indicating a counter-intuitive orbital motion in opposite handedness of the angular momentum carried by the incident waves. Moreover, analytical formulas for the spin torque, which is divided into spin torques induced by electric and magnetic dipoles, are derived. The corresponding components of both the optical spin and orbital torques are numerically calculated, and the effects of polarization, the order of the beam, and half-cone angle are discussed in detail. The left-handed (i.e., negative) optical torque is discussed, and the conditions for generating optical spin and orbital torque sign reversal are numerically investigated. The transverse optical spin torque has a vortex-like character, whose direction depends on the polarization, the half-cone angle, and the order of the beam. Numerical results also show that the vortex direction depends on the radial position of the particle in the transverse plane. This means that a sphere may rotate with different directions when it moves radially. Potential applications are in particle manipulation and rotation, single beam optical tweezers, and other emergent technologies using vector Bessel beams on a small magneto-dielectric (nano) particle. [ABSTRACT FROM AUTHOR]

The optical radiation force (ORF) and optical spin torque (OST) on an absorptive electromagnetic conductor (AEMC) sphere by an arbitrary-shaped optical polarized beam are investigated in the framework of the generalized Lorenz–Mie theory (GLMT). The analytical expressions of ORF and OST are derived, and both of them are decomposed into three components (co-polarized, cross-polarized, and interference components) due to the unique "optical rotation" effect of the AEMC. The ORF and OST exerted on both a PEMC and an AEMC sphere by an Airy beam are discussed, and the impact of the losses M i of AEMC is focused on. Besides, the influence of particle size parameter k a and admittance parameter M on the ORF and OST are also mainly analyzed. The optical pulling force built on this system is paid attention to and discussed. And the impact of the polarization states of the incident beam on the ORF and OST is also discussed. Furthermore, the comparison of ORF that the Airy beam interacts with a dielectric sphere and an AEMC sphere is studied emphatically. The findings in this manuscript will take effect on particle manipulation, optical spanners, optical tweezers, and metamaterial field. • The optical radiation force and torque exerted on an absorptive electromagnetic conductor (AEMC) sphere by an arbitrary-shaped optic. • The co-polarized, cross-polarized, and interference components of the optical radiation force and torque are studied. • Both the longitudinal and the transversal optical radiation force (including the optical pulling force) and torque are analyzed. • The comparison of ORF that the Airy beam interacts with a dielectric sphere and an AEMC sphere is studied. • The effects from the beam parameters of Airy beam and particle parameters are analyzed. [ABSTRACT FROM AUTHOR]

An analytical description of optical force on a Rayleigh particle by a vector Bessel beam is investigated. Linearly, radially, azimuthally, and circularly polarized Bessel beams are considered. The radial, azimuthal, and axial forces by a vector Bessel beam are numerically simulated. The effect of polarization, order of beams, and half-cone angle to the optical force are mainly discussed. For Bessel beams of larger half-cone angle, the non-paraxiality of beams plays an important role in optical forces. Numerical calculations show that optical forces, especially azimuthal forces, are very sensitive to the polarization of beams. [ABSTRACT FROM AUTHOR]

Debye series expansion is employed to the analysis of radiation pressure force exerted on a spherical particle induced by an axicon-generated Bessel beam. The beam shape coefficients for Bessel beams are calculated using analytical expressions obtained by the integral localized approximation, and the scattering coefficients are expanded using Debye series. The effect of different parameters (beam center location, radius of particle, half-cone angle, etc.) on radiation pressure force is studied. The contributions of different scattering processes on radiation pressure force are isolated for better understanding of physical mechanism of various features of radiation pressure force. [ABSTRACT FROM PUBLISHER]

• The generalized Lorenz-Mie theory (GLMT) for a laser beam of arbitrary shape illuminating a perfect electromagnetic conductor (PEMC) sphere is presented. • The precise expressions of the total electric field intensity, the scattering efficiency, and its components are attained by the GLMT. • The effects of dimensionless size and admittance parameter on the total electric field intensity and the scattering efficiency are calculated and analyzed. • The effects of wave parameters on the scattering efficiency are calculated and discussed. The generalized Lorenz-Mie theory (GLMT) for a laser beam of arbitrary shape illuminating a perfect electromagnetic conductor (PEMC) sphere is presented. Making use of the vector angular spectrum decomposition method (VASDM), and the multipole expansion method (MEM), in which any beam is expressed in terms of vector spherical wave functions (VSWFs) and beam shape coefficients (BSCs), the BSCs are obtained and expressed by a vector angular spectrum. The incident and scattering waves are expanded using VSWFs. A relation between the coefficients of the scattering fields and the BSCs of the incident beam is established considering the appropriate boundary conditions at the surface of the PEMC sphere. Expressions for the extinction, scattering, and absorption cross-sections are derived and computed. By isolating the co-polarization and cross-polarization components of the scattering coefficients, individual expressions of these physical quantities are also provided. Considering the vector Bessel and Airy polarized beams as examples, the total electric field intensity, scattering cross-section and its co-polarized and cross-polarized components are numerically computed and discussed. The effects of beam polarization, size parameter of the sphere, the admittance M , and beam parameters are analyzed. It has been found that the intensity and distribution of the total (incident + scattered) electric field intensity in the transverse (y z) plane depends on the incident beam characteristics and its polarization states. As the dimensionless size k a increases, the amplitude of the scattering cross-section increases and then decreases as k a increases. As the admittance parameter M changes, there are different characteristics if the incident beam is different. Nonetheless, there is a common behavior that the trend of the co-polarized component of the scattering cross-section decreases first and then increases regardless of the beam and its polarization state. When it comes to the trend of the cross-polarized component versus M , it is opposite to that of the co-polarized component. A few resonance peaks are manifested in the plots when the incident beam is radially or azimuthally polarized. The results may have promising applications in scattering, particle manipulation, optical trapping, and other related researches dealing with a sphere exhibiting rotary polarization. [ABSTRACT FROM AUTHOR]

• The generalized Lorenz-Mie theory (GLMT) for a laser beam of arbitrary shape illuminating a perfect electromagnetic conductor (PEMC) sphere is presented. • The precise expressions of the total electric field intensity, the scattering efficiency, and its components are attained by the GLMT. • The effects of dimensionless size and admittance parameter on the total electric field intensity and the scattering efficiency are calculated and analyzed. • The effects of wave parameters on the scattering efficiency are calculated and discussed. The generalized Lorenz-Mie theory (GLMT) for a laser beam of arbitrary shape illuminating a perfect electromagnetic conductor (PEMC) sphere is presented. Making use of the vector angular spectrum decomposition method (VASDM), and the multipole expansion method (MEM), in which any beam is expressed in terms of vector spherical wave functions (VSWFs) and beam shape coefficients (BSCs), the BSCs are obtained and expressed by a vector angular spectrum. The incident and scattering waves are expanded using VSWFs. A relation between the coefficients of the scattering fields and the BSCs of the incident beam is established considering the appropriate boundary conditions at the surface of the PEMC sphere. Expressions for the extinction, scattering, and absorption cross-sections are derived and computed. By isolating the co-polarization and cross-polarization components of the scattering coefficients, individual expressions of these physical quantities are also provided. Considering the vector Bessel and Airy polarized beams as examples, the total electric field intensity, scattering cross-section and its co-polarized and cross-polarized components are numerically computed and discussed. The effects of beam polarization, size parameter of the sphere, the admittance M , and beam parameters are analyzed. It has been found that the intensity and distribution of the total (incident + scattered) electric field intensity in the transverse (y z) plane depends on the incident beam characteristics and its polarization states. As the dimensionless size k a increases, the amplitude of the scattering cross-section increases and then decreases as k a increases. As the admittance parameter M changes, there are different characteristics if the incident beam is different. Nonetheless, there is a common behavior that the trend of the co-polarized component of the scattering cross-section decreases first and then increases regardless of the beam and its polarization state. When it comes to the trend of the cross-polarized component versus M , it is opposite to that of the co-polarized component. A few resonance peaks are manifested in the plots when the incident beam is radially or azimuthally polarized. The results may have promising applications in scattering, particle manipulation, optical trapping, and other related researches dealing with a sphere exhibiting rotary polarization. [ABSTRACT FROM AUTHOR]

Abstract: The scattering of an axicon-generated Bessel beam (AGBB) by a sphere is investigated. An analytical formula for the calculation of Beam Shape Coefficients (BSCs) of an AGBB is first derived according to the Integral Localized Approximation (ILA). After the verification of BSCs by the comparison of the reconstructed field using BSCs with the original field obtained from the definition, the far-field scattered intensity is evaluated, and the rainbow produced by AGBB is also studied. The effect of angle on the far-field scattered intensity and the first rainbow is analyzed in detail. Such investigation could provide a useful tool for the research on radiation forces and torques, which is important in optical tweezers and the related optical manipulation applications. [Copyright &y& Elsevier]

Abstract: Debye series expansion (DSE) is employed to the analysis of radiation pressure force (RPF) exerted on biological cells induced by high-order Bessel beams (BB). The beam shape coefficients (BSCs) for high-order Bessel beams are calculated using analytical expressions obtained by the integral localized approximation (ILA). Different types of cells, including a real Chinese Hamster Ovary (CHO) cell and a lymphocyte which are respectively modeled by a coated and five-layered sphere, are considered. The RPF induced by high-order Bessel beams is compared with that by Gaussian beams and zeroth-order Bessel beams, and the effect of different scattering processes on RPF is studied. Numerical calculations show that high-order Bessel beams with zero central intensity can also transversely trap particle in the beam center, and some scattering processes can provide longitudinal pulling force. [Copyright &y& Elsevier]

Based on Lighthill acoustic analogy theory and combining boundary element method ( BEM) with computational fluid dynamics ( CFD), the pulsating pressure data of flow field boundary are input into the BEM model for a passenger car, and the boundary conditions of aerodynamic dipole sound source near car surface are obtained through conversion and calculation. A numerical simulation on the external radiation sound field of vehicle aerodynamic noise is conducted by using direct BEM. The results show that the intensity of dipole sound source on car surface decreases with the increase of frequency, the sound pressure level of aerodynamic noise near rearview mirrors is up to some 78 dB at 2,000Hz with a vehicle speed of 120km/h, and at the same frequency, the radiation intensity of aerodynamic sound source on the longitudinal symmetric plane of vehicle is larger than that on horizontal plane. [ABSTRACT FROM AUTHOR]

• The scattering of a non-paraxial Bessel pincer light-sheet by a dielectric sphere of arbitrary size is investigated using GLMT. • The BSCs of the Bessel pincer light-sheet are calculated using ASDM and VSWFs. • The incident, scattering, internal and near-surface fields are numerically analyzed. • The absorption and extinction efficiencies are analyzed. • The influences of the scaling parameter and order of the Bessel pincer light-sheet are discussed. The scattering of a non-paraxial Bessel pincer light-sheet by a dielectric sphere of arbitrary size is studied in the framework of generalized Lorenz-Mie theory (GLMT). The electrical field of the Bessel pincer light-sheet is expanded using the vector angular spectrum decomposition method (VASDM), and its beam shape coefficients (BSCs) are derived using the method of multipole expansion and vector spherical wave functions (VSWF). By this way, the incident field, scattering field and near-surface field, and absorption and extinction efficiency factors are numerically calculated. Also, the effects of the beam order, scaling parameter, and polarization are mainly discussed. Numerical results represent that the intensity distribution of incident field, scattering field and near-surface field is intensely sensitive to the scaling parameters and the beam order. For the incident field, the bigger the order, the smaller the bending angle, and the closer the focus is to the source. By contrast, for the scattering and total field, the bigger the order, the larger the bending angle, and the farther the focus is to the source. Such results have potential applications in the imaging around steep corners and particle manipulation applications with minimal obstruction by particles. [ABSTRACT FROM AUTHOR]

• The optical resonance scattering of a dielectric lossless sphere of arbitrary size illuminated by a polarized Airy beam is studied using the GLMT. • The BSCs of the polarized Airy beams are calculated using VASDM and VSWFs. • The influences of beam polarization, attenuation parameter γ and transverse scale ω 0 of the incident Airy beam are discussed. • The scattering and extinction, "resonance" and "interference" efficiencies are examined under different parameters. • The scattering efficiency for a perfectly conducting sphere, the normalized far-field scattering intensity and its resonance counterpart are calculated and plotted. The optical resonance scattering of a dielectric sphere of arbitrary size illuminated by a polarized Airy beam is studied using the generalized Lorenz–Mie theory (GLMT). The electric field is derived using the vector angular spectrum decomposition method (VASDM). The beam shape coefficients (BSCs) are obtained using the multipole expansion method involving vector spherical wave functions (VSWFs). The resonance scattering characteristics are calculated using the GLMT by subtracting a non-resonant background of a perfectly conducting impenetrable sphere. The effects of beam polarization (i.e., linear, circular, radial, azimuthal, and mixed), the attenuation parameter γ and the dimensionless transverse scale kω 0 of the incident Airy beam on the scattering and extinction, "resonance" and "interference" efficiencies are examined. Moreover, the scattering efficiency for a perfectly conducting sphere as well as the three-dimensional (3D) scattering directivity patterns of the normalized dimensionless far-field scattering intensity and its resonance counterpart are calculated and plotted. The analysis of the resonance scattering shows that the energy efficiency is not the mere sum of resonance and perfectly conducting background terms; there is an interference between the two denoted by Q s c a i n t e r f , which strongly affects the resonance extinction and scattering efficiencies. The results presented here are of some importance in studying the optical resonance scattering of polarized Airy beams in applications involving imaging, particle sizing, radiation forces and torques to name a few areas of research. [ABSTRACT FROM AUTHOR]

• The scattering of a non-paraxial Bessel light-sheet by a sphere of arbitrary size is investigated using GLMT. • The BSCs of the Bessel light-sheet are calculated using ASDM and VSWFs. • The incident, internal and near-surface fields are numerically calculated. • The absorption and extinction efficiencies are analyzed. • The influences of the order and half-cone angle of the Bessel light-sheet are discussed. The scattering of a non-paraxial Bessel light-sheet by a sphere of arbitrary size is studied in framework of generalized Lorenz-–Mie theory (GLMT). The electrical fields of the Bessel light-sheet are expanded using the vector angular spectrum decomposition method (VASDM), and the beam shape coefficients (BSCs) of the Bessel light-sheet are derived using the method of multipole expansion and vector spherical wave functions (VSWF). The internal and near-surface fields, and absorption and extinction efficiency factors are numerically calculated when a Bessel light-sheet is incident, and the effects of beam's order, and half-cone angle are mainly discussed. Numerical results show that there is strong point convergence in the forward scattering region under the incident of a Bessel light-sheet, and the internal and near-surface fields of Bessel light-sheet are very sensitive to the beam's order, half-cone angle, etc. Such results have potential applications in the super-resolution imaging using a light-sheet microscopy. [ABSTRACT FROM AUTHOR]

• Optical force on a sphere of arbitrary size illuminated by an Airy lightsheet is investigated using GLMT. • The BSCs of the Airy light-sheet are calculated using ASDM and VSWFs. • The negative longitudinal optical force is particularly emphasized. • The two kinds of polarizations (TE and TM) of Airy light-sheet are discussed. • The influences of the transverse scale parameter ω 0 and attenuation parameter γ of the Airy light-sheet are discussed. Based on the generalized Lorenz–Mie theory (GLMT) and the angular spectrum decomposition method (ASDM), we calculate the optical radiation force exerted on a lossless dielectric sphere of arbitrary size illuminated by an Airy light-sheet. The beam shape coefficients (BSCs) of the Airy light-sheet are calculated using the vector angular spectrum decomposition and vector spherical wave functions methods. The optical radiation force acting on the spherical particle is obtained by the integral of Maxwell's stress tensor. The transverse (F y) and longitudinal (F z) forces are numerically computed. Two kinds of polarization (TE and TM) are considered for the Airy light-sheet, and the negative longitudinal optical (pulling) force is particularly emphasized. The influence of the transverse scale parameter w 0 and attenuation parameter γ of the Airy light-sheet on the force is discussed. The results of the present theory are verified using the dipole approximation method in which the gradient force has been also computed for a Rayleigh sphere. The numerical results show that when the transverse scale parameter w 0 and attenuation parameter γ increase, the transverse and longitudinal forces decrease. Furthermore, the force caustic (i.e., maximum) shifts to the direction of y < 0 as the transverse scale parameter w 0 increases. As the dimensionless size parameter of the sphere ka increases (where k is the wavenumber and a is the radius), the resonance peaks of the optical forces become larger. The results of this paper are of practical significance for the development of Airy light-sheet based optical manipulation technologies. [ABSTRACT FROM AUTHOR]

• Photonic jet generated by an ellipsoid is investigated using DDA. • The influences of ellipticity, particle size, wavelength, and refractive index are discussed. • The focal intensity, focal length and FWHM of photonic jet were calculated under different parameters. • The focal intensity, focal length and FWHM of photonic jet can be adjusted by choosing suitable parameters. The photonic jet generated by an ellipsiod illuminated by a plane wave is investigated. The open-source software DDSCAT is used in our calculation. The influences of polarization, ellipticity, particle size, the wavelength of the incident wave and the relative refractive index of the particle to the surrounding medium on the jet intensity, waist width, and length are analyzed. Numerical results show that we can manipulate the main characteristics of photonic jet by changing the above five parameters. These results of photonic jet can help us to achieve a nanoantenna with the function of generating a specific beam. [ABSTRACT FROM AUTHOR]

The scattering of x linearly polarized non-diffracting Lommel beam by a perfect electromagnetic conductor (PEMC) sphere is analyzed within the generalized Lorenz–Mie theory (GLMT) framework. The electromagnetic fields of the incident Lommel beams are expressed by employing spherical vector wave functions (SVWFs) and beam shape coefficients (BSCs). These BSCs are mainly considered in the expression of shaped beams in the GLMT with slight beam axicon angle. The scattered electromagnetic fields are constructed using unknown scattering field coefficients (SFCs) and SVWFs. These undetermined SFCs are calculated employing boundary conditions (BCs) at the PEMC surface. The expressions of the far-region/far-zone scattering intensity (FSI) are given and computed. The influences of Lommel beam configuration parameters like as beam order, beam half cone angle, beam asymmetry parameter, beam center coordinates positions, and PEMC sphere size parameter in addition to PEMC scalar admittance on the FSI are analyzed and discussed. The experience of this research work will be quite helpful in analyzing optical radiation force and torque, electromagnetic scattering, light manipulation, antenna engineering domain, optical tweezers, particle interaction, and trapping. Moreover, findings of the study can also be extended to study the interaction between the non-diffracting Lommel beam and the metamaterial structures. [ABSTRACT FROM AUTHOR]

The optical force exerted on a Rayleigh dielectric spherical particle by a photonic jet is investigated in the framework of the Rayleigh approximation. The photonic jet is generated by a plane wave illuminating a Generalized Luneburg Lens (GLLs). The electric field of the photonic jet is calculated using Discrete Dipole Approximation (DDA). The effects of wavelength of incident plane wave, focal length and radius of the GLLs on optical force are analyzed. Numerical results show that the stability of the captured particles can be controlled by changing the incident wavelength, focal length and radius of the GLLs. [ABSTRACT FROM AUTHOR]

The interaction of a vector Bessel-Gaussian beam (VBGB) with a dielectric sphere is investigated in the framework of generalized Lorenz–Mie theory (GLMT). The electric field of a VBGB is derived using the angular spectrum decomposition method (ASDM), and the analytical expressions of beam shape coefficients (BSCs) are derived utilizing multipole expansion method using vector spherical harmonics. Various polarizations including linear, circular, radial, and azimuthal polarizations are considered. The far-field scattered intensities are numerically computed, and numerical results show that the beam parameters (including beam-waist radius w 0 , location of beam center, half-cone angle θ b , and polarization type) strongly affect the far-field scattered intensities. The internal and near-surface fields are also calculated, and numerical results show that for smaller θ b two curves formed by extreme peaks can be observed, and for larger θ b such curves disappear and local enhancement of electric fields on the surface can be observed. Such results have important applications in various fields, including particle sizing, optical trapping and manipulation, etc. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) quantitative measurements of reacting multiphase micro-objects are of great interest in fuel particle combustion, which is composed of an inner fuel particle and an outer gas flame. Three models of digital inline holography of this composite fuel particle in the framework of light scattering and diffraction theories have been proposed, and then verified with reported experimental observations. Results show that the dispersed fuel particle and the gas flame distinguish in the reconstructed amplitude and phase contrast images, and reveal that the low extinction efficiency and phase shifting of the highly transparent, weakly scattering gas flame accounts for the difference. [ABSTRACT FROM AUTHOR]

• The optical radiation force and torque exerted on a perfect electromagnetic conductor (PEMC) sphere by an arbitrary-shaped optical polarized beam based on the generalized Lorenz-Mie theory (GLMT). • The co-polarized, cross-polarized, and interference components of the optical radiation force and torque are studied. • Both the longitudinal and the transversal optical radiation force and torque are analyzed and discussed. • The effects from the beam parameters (the order and the hale-cone of the Bessel beam) and particle parameters (the dimensionless size parameter and admittance parameter of the PEMC sphere) are analyzed. Following the previous work [Journal of Quantitative Spectroscopy & Radiative Transfer 281 (2022) 108101], which studied the scattering of an arbitrary-shaped optical polarized beam by a perfect electromagnetic conductor (PEMC) sphere, this paper is devoted to the optical radiation force (OF) and spin torque (OST) exerted on a PEMC sphere by an arbitrary-shaped optical polarized beam based on the generalized Lorenz-Mie theory (GLMT) frame. The analytical expressions of OF and OST on a PEMC sphere are derived according to the multipole expansion method (MEM) and angular spectrum decomposition method (ASDM). The numerical results of the OF and OST and their co-polarized, cross-polarized, and interference components expound on the influence of the particle parameters (admittance parameter M and dimensionless size parameter k a) and the beam parameters (polarization, order l , and half-cone angle α 0). The negative axial OF and the negative axial reverse OST that are sensitive to the α 0 and the polarization states of the Bessel beam are highlighted. Besides, the resonance phenomenon when the high order Bessel beam with a larger α 0 illuminates the PEMC (AEMC) is discussed and analyzed. The absorptive PEMC (AEMC) sphere with losses M i is also paid attention to. And the transversal OF and OST are discussed, emphasizing the vortex characteristics which are sensitive to the M and beam parameters. The above findings have broad application prospects in optical spanners, microparticle manipulation, and optical tweezers. [ABSTRACT FROM AUTHOR]

The scattering of a cylindrical vector beam by a sphere is investigated within the framework of the generalized Lorenz–Mie theory (GLMT). The beam shape coefficients for cylindrical vector beams are calculated using analytical expression obtained by the integral localized approximation (ILA), and the scattering coefficients are expanded using Debye series (DSE). The beam shape coefficients are verified by the comparison of original field with reconstructed one. The far-field scattered intensities are numerically simulated, and the rainbows produced by the interaction of cylindrical vector beams and spherical particles are analyzed in detail. Numerical results show that far-field scattered intensity (including rainbow intensity) is very sensitive to the angle of cylindrical vector beams. [ABSTRACT FROM AUTHOR]

The exact expression of the wave vector inside a spinning homogeneous dielectric sphere illuminated by polarized plane waves is derived utilizing the "instantaneous rest-frame" hypothesis and Minkowski's theory. On this basis, the analytical expressions of the electromagnetic field in the rotation sphere system are attained. The asymmetry of the system is discussed, in which the cause is emphasized. The influence of the polarization states and rotation angular velocity on the scattering are analyzed, including the optical rotation effect and photonic hook (PH). The results of this manuscript have extensive application prospects in optical tweezers, particle manipulation, and antenna design. • The scattering of rotating dielectric spheres to polarized plane waves with different transmission directions is discussed. • The asymmetry of the scattered field induced by rotation is analyzed, and the reasons are explored. • The effect of the polarization states of the incident plane wave on the asymmetry of the rotation system is highlighted. • The optical rotation effect and photonic hook (PH) generated by rotation are discussed. [ABSTRACT FROM AUTHOR]

In the framework of Generalized Lorenz–Mie theory (GLMT), based on the expansion results of electromagnetic field radiation components of Bessel pincer light sheets beam acting on dielectric particles of arbitrary size, the expression of radiation force components in a Cartesian coordinate system is obtained by using the Maxwell stress tensor method. On the one hand, the effects of the refractive index and the equivalent radius of spherical particles on the distribution of radiation force are discussed; On the other hand, the influence of beam scaling parameter and beam order of Bessel pincer light sheets beam on the distribution of radiation force are investigated. The results indicate that the changes of particle's refractive index and effective radius only affect the distribution of radiation force. However, the beam scaling parameter and beam order of Bessel pincer light sheets beam have a very sharp impact on the convergence position, distribution range and bending degree far away from the wave source of the radiation force. Single-beam optical tweezers using the self-focusing and self-bending Bessel pincer light-sheets beam are crucial for applications such as single molecule biophysics, optical manipulation and particle separation/clearing. [ABSTRACT FROM AUTHOR]

In this paper, we obtain the intensity and phase distributions of the scattering and external fields of a vector Bessel–Gaussian vortex beam in the far-field region after being scattered by a particle. In our analysis, we use the Generalized Lorenz–Mie theory (GLMT) and the angular spectrum decomposition method (ASDM). The orbital angular momentum (OAM) spectra of the fields are analyzed by using the spiral spectrum expansion method, which is a frequently used tool for studying the propagation of vortex beams in turbulent atmospheres. Both scattered and external fields show a significant difference in spiral spectra for particles with different characteristic parameters, such as the size and complex refractive index. We also examine sampling the phase along with a circle and show that it is unable to fully express the information of the fields. This study can provide a theoretical basis for the inversion of characteristic parameters of the Bessel–Gaussian vortex beam and spherical particle by OAM spectra with applications in remote sensing engineering. [ABSTRACT FROM AUTHOR]

Abstract: On the basis of the Shannon sampling theorem, we present a relationship between the maximal scattering angle step and the radius of particles in the calculation of light scattering intensity distribution. For the first rainbow intensity application, the relationship between the maximal scattering angle step and radius of particles is derived from that between the ripple frequency and radius and refractive index of particles using this method. For the geometrical-optics approximation, the incident angle is used to calculate the scattering intensity distribution. To get the highest speed, the maximal incident angle step is necessary. The relationship between the maximal step of incident angle and radius of particles is deduced from the maximal scattering angle step equation. As indicated by our result, the maximal step of the incident angle is not a constant and it varies with incident angle. [ABSTRACT FROM AUTHOR]

In this article, we study the optical force exerted on nanorods. In recent years, the capture of micro-nanoparticles has been a frontier topic in optics. A Photonic Jet (PJ) is an emerging subwavelength beam with excellent application prospects. This paper studies the optical force exerted by photonic jets generated by a plane wave illuminating a Generalized Luneburg Lens (GLLs) on nanorods. In the framework of the dipole approximation, the optical force on the nanorods is studied. The electric field of the photonic jet is calculated by the open-source software package DDSCAT developed based on the Discrete Dipole Approximation (DDA). In this paper, the effects of the nanorods' orientation and dielectric constant on the transverse force Fx and longitudinal force Fy are analyzed. Numerical results show that the maximum value of the positive force and the negative force are equal and appear alternately at the position of the photonic jet. Therefore, to capture anisotropic nanoscale-geometries (nanorods), it is necessary to adjust the position of GLLs continuously. It is worth emphasizing that manipulations with nanorods will make it possible to create new materials at the nanoscale. [ABSTRACT FROM AUTHOR]

Abstract: An efficient numerical procedure for computing the scattering coefficients of a radially stratified tilted cylinder is discussed. Compared with the previous algorithms, computations for scattering field in our code are extended to fairly large parameters, up to more than 10,000 and a few millions in the number of layers, and computational time is only a few seconds. The capabilities of our code depend also on the memory of the computer. The algorithm can also be used for absorbing or nonabsorbing cylinders in different electromagnetic wave bands. Compared with the known results, the algorithm is validated. At last, the algorithm is used to simulate the intensity distributions of two-layered cylinders with large size parameter and of graded-index polymer optical fiber (GI-POF) at tilted incidence, which supplies information on non-intrusive measurement on-line of refractive index profile by light scattering. [Copyright &y& Elsevier]

• The optical torque exerted on a Rayleigh dielectric spherical particle by a photonic jet is investigated using Rayleigh approximation. • Photonic jet generated by a Generalized Luneburg Lens is investigated using DDSCAT. • The effects of wavelength of incident plane wave, focal length and radius of the GLLs on optical orbital torque and optical spin torque are analyzed. • The magnitude and range of positive and negative torques can be changed by choosing suitable parameters. The optical torque exerted on a dielectric Rayleigh spherical particle by photonic jet is investigated. In the study of optical torque by dipole approximation, orbital and spin torques are usually considered. Optical Orbital Torque (OOT) is a type of optical torque that causes a particle to rotate along the optical axis, and the rotation of a tiny particle around its center of mass is caused by Optical Spin Torque (OST). The photonic jet is generated by a plane wave illuminating a dielectric Generalized Luneburg Lens (GLLs). The effects of wavelength, focal length and radius of the GLLs on the OOT and OST are analyzed in this paper. The numerical results show that the wavelength and focal length of GLLs greatly affect the optical orbital torque. Optical spin torques contain a large amount of negative torques and are sensitive to the focal length of the GLLs. The results of this paper are expected to provide theoretical support for the manipulation and rotation of the Rayleigh particle. [ABSTRACT FROM AUTHOR]

A new method, called the SO-DGTD method, for solving time-dependent Maxwell's equations via the discontinuous Galerkin time domain (DGTD) method in dispersive media is presented. The shift operator (SO) method is used to represent the constitutive relations. This method has a universal equation for dispersive media models, i.e. the Debye model, the Drude model, and the Lorentz model. The algorithm is validated by studying the radar cross-section (RCS) of a hybrid dispersive sphere and a suddenly created plasma problem. [ABSTRACT FROM AUTHOR]

• Optical torque exerted on an absorptive dielectric sphere of arbitrary size illuminated by a polarized Airy light-sheet is investigated using GLMT. • The negative optical torque is particularly emphasized. • The influence of the transverse scale parameter w 0 and attenuation parameter y of the Airy light-sheet on the torque is discussed. Based on the generalized Lorenz-Mie theory (GLMT) and the angular spectrum decomposition method (ASDM), we calculate the time-averaged optical (spin) torque (OST) exerted on an absorptive dielectric sphere of arbitrary size illuminated by a TM polarized Airy light-sheet, and the negative optical torque is particularly emphasized. The influence of the transverse scale parameter w 0 and attenuation parameter γ of the Airy light-sheet on the torque is discussed. The numerical results show that both w 0 and γ have impact on the amplitude and spatial distributions of the OST. Furthermore, the OST amplitude depends on the position of the sphere in the transverse plane of wave propagation. In addition, the OST for a TE-polarized Airy light-sheet illuminating the absorptive dielectric sphere vanishes due to some symmetry considerations related to the vertical polarization property of the electric field vector. The results are of some practical significance for the development of Airy light-sheet based optical rotation of a suspended particle in light-sheet tweezers. [ABSTRACT FROM AUTHOR]

• Investigation into the polarization characteristics of Bessel vortex beams reflected and transmitted by stratified uniaxial anisotropic slabs. • Deriving a close form of the expansion coefficients of the reflected and transmitted beams. • Analyzing the influence of the lossy characteristic of uniaxial anisotropic slabs to the propagation of Bessel vortex beams. • Exploring the effects of polarization mode on the distribution of orbital angular momentum of Bessel vortex beams. The reflection and transmission of a Bessel vortex beam incident on a stratified uniaxial anisotropic slab are analytically solved by use of the expansion of cylindrical vector wave functions (CVWFs). This work is an extension of our previous paper, in which the reflection and transmission of a Bessel vortex beam incident on a homogeneous uniaxial anisotropic slab were studied. A closed form of the expansion coefficients of the reflected and transmitted beams for a stratified slab is derived. Taking a three-layered uniaxial anisotropic slab as an example, the characteristics of the reflected and transmitted beams and its influencing factors are numerically analyzed, including the magnitude profiles of the electric field components, the energy conversion between the two transverse electric components, and the distortion of orbital angular momentum (OAM) states. The results indicate that the effects of the dielectric properties of each layer on the magnitude profiles of the reflected field components are prominent, while those of the transmitted beams are opposite, which could be applied in the design of optical devices. Compared with other polarization modes, the polarization perturbation for the circularly polarized caseis very slight. As for the oblique incidence, an increase of the incident angle can obtain a high-quality reflected beam with fewer derived OAM states, and the lossy media can also do the same. Since the uniaxial anisotropic media has many applications in optical communication, radar detection, microwave device manufacture, etc., and vortex beams are proved to increase the channel capacity of an optical communication systems, these numerical results are of use in optical communications, for example, reducing the crosstalk in optical communication. [ABSTRACT FROM AUTHOR]

Highlights • The scattering of an Airy light-sheet by a non-spherical particle is investigated using DDA. • The internal and near fields are numerically calculated, and the effects of beam parameters are mainly discussed. • Wave jets generated by the interaction of an Airy light-sheet with a cube are analyzed. Abstract The scattering of an Airy light-sheet by a non-spherical particle is investigated using the discrete dipole approximation (DDA). The internal and near-surface fields of the cube placed in an Airy light-sheet are calculated, and the effects of the transverse dimension factor w 0 , the attenuation factor a , and beam center z 0 are mainly discussed. w 0 can increase the number of side lobes incident on the target, thereby increase the wave jet energy. Increasing the attenuation coefficient a leads to less wave jet energy. By moving the light-sheet, the side lobe of the incident light-sheet increases, and the wave jet energy increases. Potential applications include optical manipulation of particles, particle sizing, optical imaging, etc. [ABSTRACT FROM AUTHOR]

Abstract A semi-analytical solution is proposed to the electromagnetic scattering by an infinite chiral circular cylinder with arbitrary monochromatic illumination. The scattered and internal fields are expanded in terms of appropriate cylindrical vector wave functions, and their expansion coefficients are determined by virtue of the boundary conditions and the projection method. As a demonstration of the theoretical procedure, the normalized internal and near-surface field intensity distributions are evaluated for a fundamental Gaussian beam, and the scattering properties are discussed briefly for different chirality parameters. [ABSTRACT FROM AUTHOR]

To study the joint effects of turbulence and fog on free-space optical (FSO) communication, a joint fog-turbulence-pointing error probability model for FSO is derived based on the random fog channel, Malaga turbulence model, and pointing error model. The closed-form expressions for the average signal to noise ratio (SNR), outage probability, average bit error rate (BER), ergodic channel capacity, and moment generating function in FSO communication under intensity modulation/direct detection are derived based on the joint model. Based on the unmanned aerial vehicle (UAV) working scenario, applying these expressions, the performance analysis of the inter-UAVs optical wave communication is implemented under the conditions for different beam widths, turbulence intensity and fog density and the pointing error caused by position, orientation, and jitter deviations. The calculated results are in good agreement with the Monte Carlo simulations. The analytical results for the average BER and outage probability show that the increase in beam width can significantly degrade the BER and outage probability, for the UAVs optical communication link. The analysis for the ergodic channel capacity shows that it increases with the increase of average transmission power; however, it increases slowly with the increase of beam width. And the increase in turbulence intensity, fog density, and drone jitter will degrade the communication performance of the system. Our study lays an important theoretical foundation for the development of FSO communication and UAV communication performance improvement in joint fog and turbulent environment. [ABSTRACT FROM AUTHOR]

Carbon nitrides are excellent candidates for extreme hardness materials. In this work, a new I4̅3m phase of C3N2 has been uncovered by replacing part of the nitrogen atoms in the cagelike diamondoid nitrogen N10 with carbon atoms. This phase is mechanically and dynamically stable up to at least 50 GPa. The elastic anisotropy of I4̅3m-C3N2 is investigated by comparing with previously proposed α-C3N2. The tensile directional dependence of Young's modulus obeys the following trend: E[111]> E[110]> E[100]. Electronic structure calculations reveal that I4̅3m-C3N2 is hole conducting. Hardness calculation shows that the I4̅3m-C3N2 is superhard with a hardness of 72.9 GPa. [ABSTRACT FROM AUTHOR]

The potential applications of complex optical fields for environmental detection have attracted a lot of attention. In this study, dusty medium is equivalent to a uniformly charged sphere and a non-uniform concentric layered sphere that satisfying the single scattering condition, respectively. The interaction between a high-order polarized Bessel Gaussian beam and a spherical particle is investigated using the generalized Lorenz–Mie theory and the angular spectrum decomposition method. The location of incident beam is considered for the first time. The extinction efficiency results of a wet charged particle are compared with those of a wet neutral particle. Simulations show that the difference in extinction between these two kinds of particles mentioned above is more evident in the smaller size parameter range, which is similar to the case of plane wave incidence. In addition, the influence of complex refractive index and size proportion of heterogeneous medium on the extinction effect is analyzed. The characteristic parameters of the incident beam are considered and find out that how they affect the differences in extinction is independent of the illuminated particle. This study lays the foundation for analyzing the transmission capacity of a Bessel Gaussian vortex beam with various parameters in a dust particle cluster. • The attenuation characteristics of a high-order polarized Bessel Gaussian beam by a uniformly charged sphere and a non-uniformly concentric sphere are studied for the first time. • The influence of the position of the incident beam on the attenuation effect is discussed. • The difference in extinction between charged and neutral particles is more evident in the smaller size parameter range, which is similar to the case of plane wave incidence. [ABSTRACT FROM AUTHOR]

• Beam shape coefficients of high-order vector Bessel-Gaussian beams are derived. • Incident beam and scatterer parameters can highly influence the scattering results. • It is not feasible to recognize the relative humidity of aerosol environment by using the differences of scattering intensities. Based on the generalized Lorenz-Mie theory (GLMT) and the angular spectrum decomposition method (ASDM), we derive the beam shape coefficients (BSCs) of high-order vector Bessel Gaussian beams (H-VBGB), and investigate the interaction mechanism of H-VBGB illuminating a spherical marine aerosol. Linear (x, y), circular (left, right), azimuthal and radial polarizations are considered. The effects of various parameters characterizing the incident beam and the aerosol on the normalized differential scattering cross section (DSCS) are investigated. Numerical results show that the normalized DSCS is very sensitive to fluctuations in the parameters, and that the distinctions of incident beams may highly influence results. The relative humidity of aerosol performs similar effects on results for all polarizations, so it is not feasible to recognize the relative humidity of aerosol environment by using the differences of normalized DSCS for various polarization states. We provide a reference for the practical use of the scattering features of non-diffractive beams illuminating spherical calibrators. [ABSTRACT FROM AUTHOR]

• The internal and near-surface fields for a charged sphere by a vector Bessel beam is investigated in the framework of GLMT. • The effects of the surface charge, polarization, order, and half-cone angle are discussed. • The local enhancements of internal and near-surface fields are analyzed. The interaction of an axicon-generated vector Bessel beam (AGVBB) with a charged sphere is investigated in the framework of generalized Lorenz–Mie theory (GLMT). The incident, internal, and scattered fields are expanded using vector spherical wave functions (VSWFs), beam shape coefficients (BSCs), and internal and scattered coefficients. An analytical expressions of beam shape coefficients (BSCs), which are derived using angular spectrum decomposition method (ASDM), are given. The internal and scattered coefficients are derived by considering the boundary conditions. The internal and near-surface electric fields of a charged sphere illuminated by AVGBBs are numerical calculated, and the effects of polarization, order of beam, half-cone angle are mainly discussed. The results are compared with that for neutral particles. The effect of the surface charge are discussed by the comparison of the results for charged spheres with that for neutral particles. Numerical results show that the internal and near-surface fields are sensitive to the surface charge. The internal fields and the near-surface fields can be locally enhanced. Internal and near-surface fields, especially its local enhancement, are very sensitive to the beam parameters, including polarization, order, half-cone angle, etc. [ABSTRACT FROM AUTHOR]