Tan Qu

Xidian University · School of Electronic Engineering

Based on the generalized Lorenz–Mie theory (GLMT) and the Fourier transform method, a theoretical approach is introduced to study the scattering of a uniaxial anisotropic sphere illuminated by an off-axis high-order Bessel (vortex) beam (HOBVB). According to the orthogonality of the associated Legendre function and exponential function, a concise e...

Due to its orbital angular momentum (OAM), optical vortex has been widely used in communications and LIDAR target detection. The OAM mode recognition based on deep learning is mostly based on the basic convolutional neural network. To ensure high-precision OAM state detection, a deeper network structure is required to overcome the problem of simila...

To improve the robustness of vortex beam transmission and detection in the face of atmospheric turbulence and to guarantee accurate recognition of orbital angular momentum (OAM), we present an end-to-end dynamic compensation technique for vortex beams using an improved cycle-consistent generative adversarial network (CycleGAN). This approach transf...

Analytical solutions to the scattering of a uniform uniaxial anisotropic sphere illuminated by an on-axis high-order Bessel vortex beam (HOBVB) are investigated. Using the vector wave theory, the expansion coefficients of the incident HOBVB in terms of the spherical vector wave functions (SVWFs) are obtained. According to the orthogonality of the a...

A full analytical theory for the reflection and transmission of an Airy beam impinging on a dielectric surface is presented. Based on the plane-wave angular spectrum expansion, the analytical expressions for the reflected and transmitted fields comprising beam modes are derived. To improve the calculation accuracy, the actual beam field retains up...

Based on the generalized Lorenz-Mie theory (GLMT), a theoretical approach is introduced to study the radiation force exerted on a uniaxial anisotropic sphere illuminated by dual zero-order Bessel beams (ZOBBs). The beams propagate with arbitrary direction, and are expanded in terms of the spherical vector wave functions (SVWFs) in the particle coor...

In an effort to address the problem of the insufficient accuracy of existing orbital angular momentum (OAM) detection systems for vortex optical communication, an OAM mode detection technology based on an attention pyramid convolution neural network (AP-CNN) is proposed. By introducing fine-grained image classification, the low-level detailed featu...

At present, 5G base stations are densely distributed in major cities based on improving user concentrations and the large demand for services in urban hotspot areas. Moreover, 5G communication requires more accurate communication propagation loss (PL) monitoring. Low-build areas, such as suburbs and rural areas, are prone to forming relatively stab...

Inverse synthetic aperture LiDAR (ISAL) breaks through the limitations of the diffraction limit and achieves ultra-long-distance radar imaging with centimeter-level resolution. However, because ISAL obtains a high resolution, it is accompanied by a high sampling rate and a large data volume, and the processing process is complicated, which is not c...

The reflection and transmission of a finite-power Airy beam incident in a dielectric slab are investigated by an analytical method. Based on the plane-wave angular spectrum expansion and Fresnel approximation, the analytical expressions of the reflected field, internal field as well as transmitted field in each region are obtained. Through numerica...

In this letter, a novel integrated physical optics (PO) method for calculating high-frequency scattering of nonplane wave is proposed, and the orbital angular momentum (OAM) wave scattering upon an electric-large metallic sphere is illustrated. A high-order Bessel wave expanded by a series of plane wave angular spectra is selected to irradiate a pe...

With the rapid development of the fifth-generation (5G) mobile communication technology, the application of each frequency band has reached the extreme, causing mutual interference between different modules. Hence, there is a requirement for detecting filtering and preventing interference. In the troposphere, over-the-horizon propagation occurs in...

Based on the generalized Lorenz Mie theory, the propagation and scattering properties of a uniaxial anisotropic spherical particle illuminated by double zero-order Bessel beams with arbitrary propagation and polarization directions are studied. The propagating and scattering characteristics are compared with those of a uniaxial anisotropic spherica...

Based on the excellent and broad prospect of the vortex beams in military application, it is necessary to evaluate the scattering characteristics of classical Bessel beam upon a perfect electrical conductor (PEC) blunt cone model of aircraft structure. First, a Bessel beam is expanded by a series of plane wave spectra. Then, combining the physical...

Conventional multiple vortex beams carrying different orbital-angular-momentum (OAM) modes propagating in different directions suffer from beam divergences along with the increasing transmission distance, which greatly limits their practical applications. This article presents a diffraction-resisting dual high-order Bessel-beam (DHOBB) generator ba...

With the improvement of SAR resolution, super-resolution SAR imaging is more and more widely used in the all-time and all-weather video surveillance and remote sensing imaging. One implementation of super-resolution SAR is that radar works in the spotlight mode. In the case with highly squinted angle and acceleration, the azimuth space variance and...

With the development of SAR imaging, the efficiency and rapidity of imaging algorithms have always been a research direction, and real-time imaging is a reflection of the speed of the imaging algorithm. For missile-borne SAR, real-time imaging is particularly important because it provides radar with a sense of the battlefield environment. In the ca...

Studying the well-known phenomenon “aurora” plays a pivotal role in investigating the solar-terrestrial coupling mechanism. A special auroral spectrograph in Antarctic Zhongshan Station constitutes a auroral observation joint system with satellite-borne sensors of the Defense Meteorological Satellite Program. Multipoint observation by this system p...

Based on Maxwell’s stress tensor and the generalized Lorenz–Mie theory, a theoretical approach is introduced to study the radiation force exerted on a uniaxial anisotropic sphere illuminated by dual counter-propagating (CP) Gaussian beams. The beams propagate with arbitrary direction and are expanded in terms of the spherical vector wave functions...

Ocean waves are complex systems with the contributions of wind waves and swells. The study on interaction mechanism between electromagnetic wave and actual sea surface is of significant importance in ocean remote sensing and engineering application, which is also helpful in the prediction and inversion of wave information. In this paper, an efficie...

The essence of wireless communication and multimedia information transmission is the propagation of electromagnetic waves in the atmosphere. Within the framework of Generalized Lorenz Mie theory, and combining the vector wave theory with the generalized multi-spheres Mie theory, the analytical solution to the scattering of the high-order Bessel vor...

Aurora, the spectacular phenomenon commonly occurring in high latitudes, is caused by the precipitation of energetic particles penetrating the Earth's atmosphere. Being the result of solar-terrestrial interactions, electron precipitation significantly contributes to auroral production. To evaluate its magnitude, a physical quantity describing the c...

In this paper, theory concerning scattering of EM (electromagnetic) waves with orbital angular momentum (OAM) is presented, in which a metallic sphere illuminated by OAM waves is adopted to simplify the study. Based on the series expansion and the physical optics (PO) methods, expressions of incident and scattered OAM waves are obtained. To get the...

THz wave has advantages in targets detecting and imaging, however, the severe atmospheric attenuation limits its application range. To perform a higher transmittance through clouds and higher resolution, upper troposphere should be considered to be the application senario of THz wave. Therefore, it is necessary to study on the atmospheric radiative...

Propagation dynamics of the cosh-Airy vortex (CAiV) beams in a chiral medium is investigated analytically with Huygens–Fresnel diffraction integral formula. The results show that the CAiV beams are split into the left circularly polarized vortex (LCPV) beams and the right circularly polarized vortex (RCPV) beams with different propagation trajector...

In this paper, the scattering characteristics an infinite dielectric periodic surface are investigated in detail. The Fourier expression of scattering field of the periodic surface is obtained by using the Rayleigh hypothesis and the Floquet theorem. Using the extended boundary condition method and the T‐matrix method, the scattering amplitude fact...

The development of embedded system makes it convenient to process SAR data in curve trajectory which caused by maneuvers with acceleration. To eliminate the effect of acceleration on imaging, a constant acceleration nonlinear chirp scaling (CA-NCS) algorithm in curve trajectory based on motion compensation is proposed. Through dividing the accelera...

The scattering characteristics of the periodic surface of infinite and finite media are investigated in detail. The Fourier expression of the scattering field of the periodic surface is obtained in terms of Huygens’s principle and Floquet’s theorem. Using the extended boundary condition method (EBCM) and T -matrix method, the scattering amplitude f...

Through this study, we demonstrate the generation of linear dual-polarization beams with different orbital angular momentum (OAM) modes by designing, manufacturing, and experimentally measuring an anisotropic holographic metasurface. A combination of the leaky-wave theory and the microwave holographic method is proposed as a way to effectively cons...

An iterative method is proposed for dealing with scattering from a multilayered chiral sphere in Lorenz-Mie regime in the authors’ previous work. In this paper the research is extended on the internal fields and near fields. By using four intermediate variables in each region of the multilayered chiral sphere, an iterative relationship of expansion...

This erratum makes corrections to Eqs. (7) and (9) of Opt. Lett. 44, 1452 (2019).OPLEDP0146-959210.1364/OL.44.001452

In this Letter, to the best of our knowledge, a novel anisotropic surface impedance holographic metasurface antenna for generating orbital angular momentum (OAM) is developed through design, fabrication, and measurement at radio frequencies. The classical leaky-wave theory and a microwave holography method are combined to realize vortex waves carry...

In this paper, an anisotropic holographic metasurface design is proposed, fabricated, and measured, to demonstrate that it can generate multiple beams with different orbital angular momentum (OAM) modes in the radio-frequency domain. The anisotropic holographic metasurface is composed of an array of quasi-periodic square particles with a rectangula...

In this letter, a novel multiple-polarization reflectarray that carries orbital angular momentum (OAM) is proposed. The coupling between the linear or circular polarization and OAM is realized using an orthogonally independent modulation of the especially designed reflective unit, with the polarization angle of the linearly polarized feed incident...

In this paper, a dual-band dual-polarized reflectarray for generating dual beams with respect to carrying two different orbital angular momentum (OAM) topological charges operating in the C-band in horizontal polarization and in the X-band in vertical polarization is proposed, with two separate horns performing on the two proposed bands as the feed...

This study investigated variation in the upwelling radiation contribution to typical remote sensing channels of temperature (50–60 GHz, 118 GHz, and 424 GHz) and water vapor (22 GHz, 183 GHz, and 380 GHz) with altitude to evaluate their sounding abilities and obtain channel sets for sounding of lower atmosphere with high resolution. The gaseous att...

Analytical solution to the scattered field and near-surface field of a multilayered chiral sphere illuminated by a high-order Bessel vortex beam (HOBVB) are investigated. Using the vector wave theory, the expansion coefficients of a HOBVB in terms of spherical vector wave functions (SVWFs) are derived. Based on the fields expansion in each region a...

Based on the generalized multi-particle Mie equation (GMM) and Electromagnetic Momentum (EM) theory, the lateral binding force (BF) exerted on bi-sphere induced by an arbitrary polarized high-order Bessel beam (HOBB) is investigated with particular emphasis on the half-conical angle of the wave number components and the order (or topological charge...

Within the framework of the generalized multi-particle Mie (GMM) theory, analytical solution to electromagnetic scattering of two interacting homogeneous uniaxial anisotropic spheres by a Laguerre–Gaussian (LG) vortex beam is investigated. The particles with different size and dielectric parameter tensor elements are arbitrarily configured. Based o...

The effective extraction of optical surface roughness and defect characteristic provide important realistic values to improve optical system efficiency. Based on finite difference time domain/multi-resolution time domain (FDTD/MRTD) mixed approach, composite scattering between a slightly rough optical surface and multi-body defect particles with di...

Due to atmospheric absorption, the signal attenuation must be considered when designing communication links in the terahertz (THz) band. The equivalent height described in International Telecommunication Union Recommendation (Rec. ITU)-R P.676 can be used to evaluate the signal attenuation over satellite links by meteorological parameters of the Ea...

Based on the generalized Lorentz–Mie theory (GLMT) and the localized approximation of the beam shape coefficients, we derived the expansions of incident elliptic Gaussian (EG) beams in terms of spherical vector wave functions (SVWFs). Utilizing multiple scattering (MS) equations and electromagnetic momentum (EM) theory, the lateral binding force (B...

The analytical theory for the scattering of a uniaxial anisotropic illuminated by a Laguerre-Gaussian vortex beam is presented. Based on the complex source point method and the relation between Hermite polynomial and Laguerre polynomial, the expansion of Laguerre-Gaussian vortex beam expanded in terms of spherical vector wave functions is derived....

This letter presents a field expansion of the solution to three-dimensional electromagnetic scattering problems of a uniaxial anisotropic spheroidal particle illuminated by an off-axis Hermite-Gaussian (HG) beam. Using the complex-source-point method, and the relationship between spherical and spheroidal vector wave functions (VWFs), a method is pu...

The expression of Hermite-Gaussian beam in terms of spherical vector wave functions is given with the complex source point method. Based on the generalized Lorenz-Mie theory, the scattering coefficients are obtained by applying the continuous boundary conditions of tangential components of electromagnetic field at the interface between chiral mediu...

Since the development of the generalized Lorenz–Mie theory, electromagnetic scattering by arbitrary beams has drawn growing interest. The Laguerre–Gaussian (LG) vortex beam is well known for its orbital angular momentum. With the aim of investigating the analytical solution to the scattering of a chiral sphere by a LG vortex beam, particular attent...

Based on the generalized multiparticle Mie theory, multiple scattering of an aggregate of uniaxial anisotropic spheres illuminated by a zero-order Bessel beam (ZOBB) with arbitrary propagation direction is investigated. The particle size and configuration are arbitrary. The arbitrary incident Bessel beam is expanded in terms of spherical vector wav...

The analytical theory for the electromagnetic (EM) scattering of plasma anisotropic sphere illuminated by a high-order Bessel beam (HOBB) is investigated in this paper. The HOBB is presented using vector wave theory in which electric and magnetic field vectors satisfy Maxwell's equations. The fields inside the plasma sphere are expressed using eige...

Rayleigh model has been proposed to deal with scattering from a small sized chiral sphere. A chiral sphere in Rayleigh size illuminated by electromagnetic waves can be substituted by four Hertzian dipoles. Thus the scattering problem is converted to a radiation problem. The four equivalent dipole moments are solved by applying the boundary conditio...

Research on light scattering from a large chiral sphere shows that the rainbow phenomenon is different from that of an isotropic sphere. A chiral sphere with certain chirality generates three first-order rainbows. In this Letter, we present a geometric optics interpretation for the phenomenon and make a calculation of the rainbow angles. The ray tr...

An analytic theory for the scattering of an off-axis Hermite-Gaussian (HG) beam obliquely incident on an anisotropic sphere is developed. Based on the complex-source-point method and coordinate rotation theory, a general expansion expression for an arbitrarily incident HG beam in terms of Spherical Vector Wave Functions (SVWFs) is derived, and its...

The beam width of Laguerre-Gaussian vortex beam is derived by using intensity momentum method. Using the expression of Hermite-Gaussian beam in terms of spherical vector wave functions by complex source point method, and combining with the transformation between Laguerre polynomial and Hermite polynomial, Laguerre-Gaussian vortex beam is expanded i...

Based on the expansion of Hermite Gaussian (HG) beam in terms of spherical vector wave functions (SVWFs) utilizing Complex Source Point Method (CSPM) and the relation between HG beam and Laguerre Gaussian (LG) mode, we derived the expansion of LG vortex beam in terms of SVWFs. Using Generalized Lorenz Mie Theory (GLMT), the radiation force (RF) exe...

Based on the generalized multi-particle Mie theory and the Fourier transformation approach, light scattering of two interacting homogeneous uniaxial anisotropic spheres with parallel primary optical axes illuminated by a zero-order Bessel beam (ZOBB) is investigated. The size and configuration of the particles are arbitrary. The expansion expressio...

By right of its non-diffracting and self-constructing property, Bessel beam has gained growing attentions from scholars since its naissance. Based on the generalized Lorenz-Mie theory (GLMT), the incident on-axis Bessel beam and scattered fields of the chiral sphere were expressed in terms of the spherical vector wave functions (SVWFs). The analyti...

Based on orthogonality of spherical vector wave functions (SVWFs), the expansion coefficients of a plane wave, with arbitrary directions of propagation and polarization, for both transverse magnetic and transverse electric modes are obtained in terms of spherical vector wave functions. The scattering of a uniaxial anisotropic sphere illuminated by...

One-dimensional range profile is known as a simple radar imaging technology. Based on the imaging mechanism, the laser range profiles (LRPS) of the convex rotators in three different methods, which named as the Beam Scattering Method (BS method), Radar Cross Section Method (RCS method) and Surface Elements Method (SE method),were studied. In detail...

Based on the scattering theory of a chiral sphere, rainbow phenomenon of a chiral sphere is numerically analyzed in this paper. For chiral spheres illuminated by a linearly polarized wave, there are three first-order rainbows, with whose rainbow angles varying with the chirality parameter. The spectrum of each rainbow structure is presented and the...

Electromagnetic scattering of a zero-order Bessel beam by an anisotropic spherical particle in the off-axis configuration is investigated. Based on the spherical vector wave functions, the expansion expression of the zero-order Bessel beam is derived, and its convergence is numerically discussed in detail. Utilizing the tangential continuity of the...

Under the framework of generalized Lorenz-Mie theory, we calculate the radiation force and torque exerted on a chiral sphere by a Gaussian beam. The theory and codes for axial radiation force are verified when the chiral sphere degenerates into an isotropic sphere. We discuss the influence of a chirality parameter on the radiation force and torque....

Based on the derivatives between the fundamental and higher-order Hermite Gaussian beam and the Davis’s one-order approximation of slowly varying function, a general expression of the higher-order Hermite Gaussian beam are presented. Scattering characteristics of higher-order off-axis Hermite Gaussian is investigated. Some selected calculations on...