检索结果-内蒙古大学图书馆

Unified matrix approach to the description of phase-space rotators

APPLIED OPTICS 2016年第7期55卷 1530-1536页

作者： Gitin, Andrey V. Tech Univ Berlin Inst Opt & Atomare Phys Sekr ER 1-1Str 17 Juni 135 D-10623 Berlin Germany

In optics, the rotation of a phase-space can be realized via light propagation through both an inhomogeneous medium with a radial gradient of refractive index and two special kinds of mirror-symmetrical optical systems suggested by Lohmann. Although light propagation through Lohmann's systems is described in terms of matrix optics, light propagation through the gradient-index medium is traditionally described as a solution of the wave equation. The difference in these descriptions hinders the understanding of the phase-space rotators. Fortunately, there is a matrix description of light propagation through a gradient-index medium too. A general description of the phase-space rotators is presented, which can be used to treat light propagation through both Lohmann's systems and the gradient-index medium in a unified matrix manner. (C) 2016 Optical Society of America

关键词： Fiber optics abcd transforms Matrix methods in paraxial optics Propagation

来源：评论

学校读者我要写书评

暂无评论

Random discrete linear canonical transform

引用

JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 2016年第12期33卷 2470-2476页

作者： Wei, Deyun Wang, Ruikui Li, Yuan-Min Xidian Univ Sch Math & Stat Xian 710071 Peoples R China Xidian Univ Sch Telecommun Engn Xian 710071 Peoples R China

Linear canonical transforms (LCTs) are a family of integral transforms with wide applications in optical, acoustical, electromagnetic, and other wave propagation problems. In this paper, we propose the random discrete linear canonical transform (RDLCT) by randomizing the kernel transform matrix of the discrete linear canonical transform (DLCT). The RDLCT inherits excellent mathematical properties from the DLCT along with some fantastic features of its own. It has a greater degree of randomness because of the randomization in terms of both eigenvectors and eigenvalues. Numerical simulations demonstrate that the RDLCT has an important feature that the magnitude and phase of its output are both random. As an important application of the RDLCT, it can be used for image encryption. The simulation results demonstrate that the proposed encryption method is a security-enhanced image encryption scheme. (C) 2016 Optical Society of America

关键词： Optical security and encryption abcd transforms Numerical approximation and analysis Digital image processing Pattern recognition optical security and encryption

来源：评论

学校读者我要写书评

暂无评论

Nonsubsampled contourlet transform method for optical fringe pattern analysis in profilometry and interferometry

引用

APPLIED OPTICS 2016年第27期55卷 7718-7725页

作者： Li, Sikun Wang, Xiangzhao Tang, Feng Bu, Yang Sasaki, Osami Chinese Acad Sci Shanghai Inst Opt & Fine Mech Lab Informat Opt & Optoelect Technol Shanghai 201800 Peoples R China Univ Chinese Acad Sci Beijing 100039 Peoples R China Niigata Univ Fac Engn Niigata 9502181 Japan

A method based on a nonsubsampled contourlet transform, which is an overcomplete transform with multiresolution, directionality, and shift-invariance properties, is proposed to extract the fundamental frequency component of an optical fringe pattern in profilometry and interferometry. The nonsubsampled contourlet transform method overcomes the disadvantages of the original contourlet transform method, which lacks the shift-invariance property. Besides, it improves the frequency selectivity. A strategy is developed to automatically determine the optimal decomposition scale for removing the background intensity and suppressing the noise of the fringe pattern. The proposed method is precise, effective, and possesses a strong noise immune ability. Simulations and experiments verify the validity, and show the superiorities of the proposed method. (C) 2016 Optical Society of America

关键词： abcd transforms Fringe analysis Phase retrieval

来源：评论

学校读者我要写书评

暂无评论

Two-dimensional nonseparable discrete linear canonical transform based on CM-CC-CM-CC decomposition

引用

JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 2016年第2期33卷 214-227页

作者： Pei, Soo-Chang Huang, Shih-Gu Natl Taiwan Univ Dept Elect Engn Taipei 10617 Taiwan Natl Taiwan Univ Grad Inst Commun Engn Taipei 10617 Taiwan

As a generalization of the 2D Fourier transform (2D FT) and 2D fractional Fourier transform, the 2D nonseparable linear canonical transform (2D NsLCT) is useful in optics and signal and image processing. To reduce the digital implementation complexity of the 2D NsLCT, some previous works decomposed the 2D NsLCT into several low-complexity operations, including 2D FT, 2D chirp multiplication (2D CM), and 2D affine transformations. However, 2D affine transformations will introduce interpolation error. In this paper, we propose a new decomposition called CM-CC-CM-CC decomposition, which decomposes the 2D NsLCT into two 2D CMs and two 2D chirp convolutions. No 2D affine transforms are involved. Simulation results show that the proposed methods have higher accuracy, lower computational complexity, and smaller error in the additivity property compared with the previous works. Plus, the proposed methods have a perfect reversibility property, meaning that one can reconstruct the input signal/image losslessly from the output. (C) 2016 Optical Society of America

关键词： Fourier optics and signal processing Paraxial wave optics abcd transforms Fractional Fourier transforms Matrix methods in paraxial optics

来源：评论

学校读者我要写书评

暂无评论

Unstable Resonators with Gosper-Island Boundary Conditions: Virtual-Source Computation of Fractal Eigenmodes

Unstable Resonators with Gosper-Island Boundary Conditions: ...

引用

Conference on Lasers and Electro-Optics Europe

作者： J. M. Christian J. G. Huang Joule Physics Laboratory University of Salford Greater Manchester M5 4WT United Kingdom Faculty of Computing Engineering and Science University of South Wales Pontypridd CF37 1DL United Kingdom

ISBN: (纸本)9781509067374

The Gosper island is a well-known fractal belonging to a family of self-similar "root 7" curves constructed from a simple iterative algorithm [1]. One begins with a regular hexagon (the initiator, corresponding to iteration n = 0) with sides of reference length l_0, and then breaks each of these straight-edge elements into three equal segments of length l_n = l_0(1/7~(1/2))~n where n = 1, 2, 3,... (the generator stages). If the total number of length elements after applying the generator n times is given by N_n = 6 × 3~n, then the Hausdorff-Besicovich dimension of such a curve is calculated to be D ≡ lim_(n→∞) -log(N_n)/log(l_n) = 2log(3)/log(7) ≈ 1.1292.

关键词： abcd transforms Apertures Fast Fourier transforms Fresnel number Optical resonators Unstable resonators

来源：评论

学校读者我要写书评

暂无评论

Propagation properties of right-hand circularly polarized Airy-Gaussian beams through slabs of right-handed materials and left-handed materials

引用

JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 2015年第11期32卷 2104-2109页

作者： Huang, Jiayao Liang, Zijie Deng, Fu Yu, Weihao Zhao, Ruihuang Chen, Bo Yang, Xiangbo Deng, Dongmei S China Normal Univ Guangdong Prov Key Lab Nanophoton Funct Mat & Dev Guangzhou 510631 Guangdong Peoples R China Chinese Acad Sci Univ Sci & Technol China CAS Key Lab Geospace Environm Hefei 230026 Peoples R China

The propagation of right-hand circularly polarized Airy-Gaussian beams (RHCPAiGBs) through slabs of right-handed materials (RHMs) and left-handed materials (LHMs) is investigated analytically and numerically with the transfer matrix method. An approximate analytical expression for the RHCPAiGBs passing through a paraxial abcd optical system is derived on the basis of the Huygens diffraction integral formula. The intensity and the phase distributions of the RHCPAiGBs through RHMs and LHMs are demonstrated. The influence of the parameter. 0 on the propagation of RHCPAiGBs through RHM and LHM slabs is investigated. The RHCPAiGBs possess transverse-momentum currents, which shows that the physics underlying this intriguing accelerating effect is that of the combined contributions of the transverse spin and transverse orbital currents. Additionally, we go a step further to explore the radiation force including the gradient force and scattering force of the RHCPAiGBs. (C) 2015 Optical Society of America

关键词： Laser beam transmission abcd transforms Left-handed materials

来源：评论

学校读者我要写书评

暂无评论

Direct measurement of particle size and 3D velocity of a gas-solid pipe flow with digital holographic particle tracking velocimetry

引用

APPLIED OPTICS 2015年第9期54卷 2514-2523页

作者： Wu, Yingchun Wu, Xuecheng Yao, Longchao Grehan, Gerard Cen, Kefa Zhejiang Univ State Key Lab Clean Energy Utilizat Hangzhou 310027 Zhejiang Peoples R China CNRS UMR CORIA 6614 F-76801 St Etienne France

The 3D measurement of the particles in a gas-solid pipe flow is of great interest, but remains challenging due to curved pipe walls in various engineering applications. Because of the astigmatism induced by the pipe, concentric ellipse fringes in the hologram of spherical particles are observed in the experiments. With a theoretical analysis of the particle holography by an abcd matrix, the in-focus particle image can be reconstructed by the modified convolution method and fractional Fourier transform. Thereafter, the particle size, 3D position, and velocity are simultaneously measured by digital holographic particle tracking velocimetry (DHPTV). The successful application of DHPTV to the particle size and 3D velocity measurement in a glass pipe's flow can facilitate its 3D diagnostics. (c) 2015 Optical Society of America

关键词： abcd transforms Aberration compensation Digital holography Three-dimensional image processing Velocimetry

来源：评论

学校读者我要写书评

暂无评论

Beam manipulating by gate-tunable graphene-based metasurfaces

引用

OPTICS LETTERS 2015年第22期40卷 5383-5386页

作者： AbdollahRamezani, Sajjad Arik, Kamalodin Farajollahi, Saeed Khavasi, Amin Kavehvash, Zahra Sharif Univ Technol Dept Elect Engn Tehran Iran

We propose an unprecedented transmit-array configuration which can mold the incident beam by modulating phase and amplitude wavefronts. The transmit-array is composed of patterned graphene metasurfaces as shunt admittance sheets. Thanks to the exceptional features of graphene such as tunability, thinness, low loss, and high confinement of graphene plasmons, the proposed subwavelength structure passes strict touchstones for nano-photonic and optoelectronic applications. Two flat-optics functionalities, i.e., focusing and splitting, are realized by means of the proposed configuration. (C) 2015 Optical Society of America

关键词： abcd transforms Lenses Beam splitters Surfaces Plasmonics

来源：评论

学校读者我要写书评

暂无评论

Propagation of Airy Gaussian vortex beams through slabs of right-handed materials and left-handed materials

引用

JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS 2015年第1期32卷 173-178页

作者： Chen, Bo Chen, Chidao Peng, Xi Deng, Dongmei S China Normal Univ Lab Nanophoton Funct Mat & Devices Guangzhou 510631 Guangdong Peoples R China Chinese Acad Sci Univ Sci & Technol China CAS Key Lab Geospace Environm Hefei 230026 Peoples R China

By using the method of the abcd matrix, the propagation of Airy Gaussian vortex (AiGV) beams through slabs of right-handed materials (RHMs) and left-handed materials (LHMs) is reported. Based on the Huygens diffraction integral, an approximate analytical propagation equation for AiGV beams is derived. Using numerical simulations, we study the intensity and phase distributions of the AiGV beams in RHMs and LHMs. We find that the optical vortex can destroy the center lobe of the AiGV beams, and the center lobe can reconstruct due to the fact that the acceleration of the vortex and the AiGV beam is not consistent. We also investigate the influence of different chi(0) values on the propagation of the AiGV beams through slabs of RHMs and LHMs, which can cause the AiGV beams to tend toward an Airy vortex beam with a smaller value and a Gaussian vortex beam with a larger one. In addition, we elucidate the energy flow and the angular momentum of the AiGV beams. (C) 2014 Optical Society of America

关键词： Laser beam transmission abcd transforms Left-handed materials

来源：评论

学校读者我要写书评

暂无评论

Constraints on additivity of the 1D discrete linear canonical transform

引用

APPLIED OPTICS 2015年第33期54卷 9960-9965页

作者： Zhao, Liang Healy, John J. Sheridan, John T. Univ Coll Dublin Sch Elect & Elect Engn SFI Strateg Res Cluster Solar Energy Convers Coll Engn & ArchitectureLab IoE2 Dublin 4 Ireland

The continuous linear canonical transform (LCT) can describe a wide variety of paraxial (quadratic phase) first-order optical systems. Digital algorithms to numerically calculate the LCT are therefore important in modeling the field propagations and are also of interest for many digital signal-processing applications. The continuous LCT is additive (and unitary), but discretization can destroy additivity. In this paper, the general constraint sufficient to ensure the discrete LCTs are additive is derived. Often, we wish to decompose the transform into a series of more computationally efficient steps. Having previously discussed the unitarity of such algorithms, in this paper we consider how our additivity constraint applies to the direct method (DM) and spectral method (SM) algorithms. Examples are presented showing how to correct nonadditive calculations and to appropriately choose parameters. (C) 2015 Optical Society of America

关键词： abcd transforms Discrete optical signal processing Digital holography

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：