A5100326722- Microwave Imaging and Scattering Analysis
- Geophysical Methods and Applications
- Numerical methods in inverse problems
- Electromagnetic Scattering and Analysis
- Chaos-based Image/Signal Encryption
- Ultrasonics and Acoustic Wave Propagation
- Near-Field Optical Microscopy
- Advanced Antenna and Metasurface Technologies
- Photonic and Optical Devices
- Digital Holography and Microscopy
- Orbital Angular Momentum in Optics
- Advanced Optical Imaging Technologies
- Advanced Fiber Optic Sensors
- Metamaterials and Metasurfaces Applications
- Advanced Steganography and Watermarking Techniques
- Advanced Fiber Laser Technologies
- Random lasers and scattering media
- Photonic Crystals and Applications
- Antenna Design and Analysis
- Advanced X-ray Imaging Techniques
- Electromagnetic Simulation and Numerical Methods
- Microwave and Dielectric Measurement Techniques
- Advanced Fluorescence Microscopy Techniques
- Plasmonic and Surface Plasmon Research
- Sparse and Compressive Sensing Techniques
Second Xiangya Hospital of Central South University
2018-2025
Central South University
2018-2025
Yangzhou University
2022-2025
Beijing Normal University
2008-2024
Yale University
2023-2024
National University of Singapore
2015-2024
Guangdong University of Technology
2023-2024
Beijing Information Science & Technology University
2022-2024
Ji Hua Laboratory
2023-2024
Sun Yat-sen University
2012-2024
We propose an improved method to retrieve the effective constitutive parameters (permittivity and permeability) of a slab metamaterial from measurement S parameters. Improvements over existing methods include determination first boundary thickness slab, selection correct sign impedance, mathematical choose branch real part refractive index. The sensitivity accuracy is also discussed. has been applied various metamaterials successful retrieval results prove its effectiveness robustness.
Information security with optical means, such as double random phase encoding, has been investigated by various researchers. It demonstrated that technology possesses several unique characteristics for securing information compared its electronic counterpart, many degrees of freedom. In this paper, we present a review technologies security. Optical systems are reviewed, and theoretical principles implementation examples presented to illustrate each system. addition, advantages potential...
Information security and authentication are important challenges facing society. Recent attacks by hackers on the databases of large commercial financial companies have demonstrated that more research development advanced approaches necessary to deny unauthorized access critical data. Free space optical technology has been investigated many researchers in information security, encryption, authentication. The main motivation for using optics photonics is waveforms possess complex degrees...
This paper is devoted to solving a full-wave inverse scattering problem (ISP), which aimed at retrieving permittivities of dielectric scatterers from the knowledge measured data. ISPs are highly nonlinear due multiple scattering, and iterative algorithms with regularizations often used solve such problems. However, they associated heavy computational cost, consequently, time-consuming. proposes convolutional neural network (CNN) technique ISPs. We introduce compare three training schemes...
In this Letter, we propose a method for optical image encryption based on diffractive imaging. An multiple random phase mask encoding system is applied, and one of the phase-only masks selected laterally translated along preset direction during process. For decryption, retrieval algorithm proposed to extract high-quality plaintext. The feasibility effectiveness are demonstrated by numerical results. can provide new strategy instead conventional interference methods, it may open up research...
This paper investigates a modified version of the subspace-based optimization method for solving inverse-scattering problems. The is found to share several properties with contrast-source-inversion method. essence that part contrast source determined from spectrum analysis without using any optimization, whereas rest by feature significantly speeds up convergence algorithm. There great flexibility in partitioning space induced current into two orthogonal complementary subspaces: signal...
A review of the most recent advances in deep learning (DL) as applied to electromagnetics (EM), antennas, and propagation is provided. It aimed at giving interested readers practitioners EM related applicative fields some useful insights on effectiveness potentialities neural networks (DNNs) computational tools with unprecedented efficiency. The range considered applications includes forward/inverse scattering, direction-of-arrival estimation, radar remote sensing, multi-input/multi-output...
In this paper, to bridge the gap between physical knowledge and learning approaches, we propose an induced current method (ICLM) by incorporating merits in traditional iterative algorithms into architecture of convolutional neural network (CNN). The main contributions proposed are threefold. First, best our knowledge, it is first time that contrast source learned solve full-wave inverse scattering problems (ISPs). Second, inspired basis-expansion strategy approach for solving ISPs, a...
We propose a method to retrieve the effective constitutive parameters of slab bianisotropic metamaterial composed split-ring resonators from measurement S parameters. Analytical inversion equations are derived for homogeneous loss-less media, and numerical retrieval approach is presented case lossy media. The verified both analytically numerically, it shown that results various resonator metamaterials qualitatively corroborate conclusions found in published papers. proposed can be used as...
Imaging of object structures using cylindrical vector beams in an aplanatic solid immersion lens (SIL) microscope is investigated. Based on a complete optical model SIL microscope, images some radial polarization, azimuthal and vortex are simulated. Some interesting imaging effects these observed. For example, counterintuitively, it found that, compared to linear circular polarizations, polarization requires larger pinhole acquire good image resolution. Similarly, shown that beam provides...
Deep learning has recently been applied to electrical impedance tomography (EIT) imaging. Nevertheless, there are still many challenges that this approach face, e.g., targets with sharp corners or edges cannot be well recovered when using circular inclusion training data. This paper proposes an iterative-based inversion method and a convolutional neural network (CNN) based recover some challenging inclusions such as triangular, rectangular, lung shapes, where the CNN-based uses only random...
We develop a phase-modulated optical system with sparse representation for information encoding and authentication. The cryptosystem is developed cascaded phase-only masks, the plaintext encoded into masks based on an iterative phase retrieval algorithm during encryption. Two simple strategies are to generate data: data randomly generated from extracted plaintext. These two sparsity respectively used in proposed security system, decrypted images cannot visually render about Optical...
Ghost imaging has become increasingly popular in quantum and optical application fields. Here, we report three-dimensional (3D) security using ghost imaging. The series of random phase-only masks are sparsified, which further converted into particle-like distributions placed 3D space. We show that either an or digital approach can be employed for the encoding. results illustrate a larger key space generated due to compared with previous works.
It is shown that graphene exhibits strong polarization-dependent optical absorption under total internal reflection. Compared with universal absorbance of 2.3%, larger was observed in monolayer, bilayer, and few-layer graphenes for transverse electric (TE) wave Our result indicates reflectance ratio magnetic to TE waves can easily provide the information number layers. Furthermore, enhanced light-graphene coupling a wide spectral range will be great potential many applications such as...
Without phase information of the measured field data, phaseless data inverse scattering problems (PD-ISPs) counter more serious nonlinearity and ill-posedness compared with full ISPs (FD-ISPs). In this article, we propose a learning-based inversion approach in frame U-net convolutional neural network (CNN) to quantitatively image unknown scatterers located homogeneous background from amplitude-only total (also denoted PD). Three training schemes different inputs CNN are proposed compared,...
A family of new integral equations (NIE) is proposed in this paper, which are transformed from the original Lippmann-Schwinger equation. It can be shown that NIE effectively reduce nonlinearity inverse scattering problems by reducing global nonlinear effects, introduced multiple behaviors, estimating contrast. Equipping previously twofold subspace-based optimization method with such NIE, inversion able to solve strong scatterers, like high contrast and/or large dimensions (in terms...
In this paper, we present a solution for autonomous exploration and reconstruction in 3-D unknown environments without priori knowledge of the environments. our framework, two-stage heuristic information gain-based next-view planning algorithm is performed to dynamically select update candidate viewpoints, followed by immediate next-best-view extraction corresponding motion planning. The planner consists frontier-based boundary coverage fixed start open travelling salesman problem solver,...
Abstract Time‐resolved photofluorochromism constitutes a powerful approach to enhance information encryption security but remains challenging. Herein, we report strategy of using hydrogen bonds regulate the time for initiating photofluorochromism. In our strategy, copolymers containing negative photochromic spiropyran (NSP), naphthalimide, and multiple hydrogen‐bonding (UPy) units are designed, which display photo‐switchable fluorescence resonance energy transfer (FRET) process from...
Based on a modal expansion of electromagnetic fields, rigorous method for analyzing surface plasmon polaritons (SPPs) periodically corrugated metal has been formulated in this paper. This takes into account the finite conductivity as well higher-order modes within grooves structure, thus is able to accurately calculate loss these spoof SPPs propagating along structured surface. In terahertz (THz) frequency range, properties dispersion and Al surfaces are analyzed. For at THz frequencies,...
Ghost imaging has attracted much attention, in which the object can be reconstructed by using correlation of intensity fluctuations. It is well known that a large number realizations (such as 5000 or even 20,000) are usually required for reconstructions ghost imaging. In this Letter, we demonstrate, first time to our knowledge, how authenticated significantly small (i.e., less than 5% Nyquist limit) computational The main objective study authenticate rather directly extract high-fidelity object.