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Numerical Solutions of finite Well in Two Dimensions Using the finite difference time domain method

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Journal of Physical Science and Application 2022年第1期12卷 12-18页

作者： Huwaida K.Elgweri Amal Hamed Mohamed Mansor Faculty of Science Physics DepartmentUniversity of TripoliTripoliLibya Faculty of Education/Janzour Physics DepartmentUniversity of TripoliTripoliLibya

The higher excited states for two dimensional finite rectangular well potential are calculated numerically,by solving the Schrödinger equation using the finite difference time domain ***,this method is suitable to calculate the ground state of the quantum systems,it has been improved to calculate the higher excited states *** improvement is based on modifying the iterative process involved in this method to include two *** first is known as cooling steps and the second is known as a heating *** determining the required length of the cooling iteration steps using suitable excitation energy estimate,and repeating these two procedures using suitable initial guess function for sufficient *** modified iteration will lead automatically to the desired excited *** the two dimensional finite rectangular well potential problem both of the suitable excitation energy and the suitable initial guess wave function are calculated analytically using the separation of variables technique.

关键词： finite difference time domain method diffusion equation separation of variables method finite well potential Schrödinger equation

Properties of the 3D photonic nanojet based on the refractive index of surroundings

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Chinese Optics Letters 2010年第7期8卷 706-708页

作者：丁红星戴丽莉闫长春 Department of Physics Lianyungang Teachers College Department of Applied Physics Nanjing University of Science and Technology School of Physics and Electronic Engineering Xuzhou Normal University

We exhibit a three-dimensional （3D） photonic nanojet based on a dielectric microsphere irradiated by a plane wave with the finite-difference time-domain （FDTD） method. We investigate the influence of the refractive index of the surrounding on the properties of the nanojet by simulating the electric field distributions in it. The simulation results show that, by optimally choosing the size of the sphere and the ratio of the refractive indices of the sphere and the surrounding, the focus point can occur just on the surface of the sphere even if the refractive index of the surrounding is changed. Additionally, the peak amplitude of the nanojet increases with increasing the refractive index of the surrounding. However, the decay length and the jet width of the nanojet decrease simultaneously. These effects may have potential applications in observation or manipulation of nano-objects such as antibodies in biology. In nanojet-enabled optical data storage, the photonic nanojet may be also helpful for improving data-storage capacities and retrieval speed by controlling the field amplitude, the decay length, and jet width of the nanojet.

关键词： Electric fields Electric properties finite difference time domain method Light refraction Optical data processing Optical data storage Organic polymers Refractive index Refractometers Three dimensional

A functional probe with bowtie aperture and bull's eye structure for nanolithograph

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Chinese Physics B 2012年第10期21卷 423-427页

作者：王硕李旭峰王乔郭英楠潘石 School of Physics and Optoelectronic Technology Dalian University of Technology School of Applied Science Taiyuan University of Science and Technology

The bowtie aperture surrounded by concentric gratings(the bull’s eye structure) integrated on the near-field scanning optical microscopy(NSOM) probe(aluminum coated fiber tip) for nanolithography has been investigated using the finite-difference time domain(FDTD) *** modifying the parameters of the bowtie aperture and the concentric gratings,a maximal field enhancement factor of 391.69 has been achieved,which is 18 times larger than that obtained from the single bowtie ***,the light spot depends on the gap size of the bowtie aperture and can be confined to *** superiority of the combination of the bowtie aperture and the bull’s eye structure is confirmed,and the mechanism for the electric field enhancement in this derived structure is analyzed.

关键词： surface plasmon polariton nanolithography finite difference time domain method

Analysis of directional emission in square resonator lasers with an output waveguide

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Chinese Optics Letters 2007年第8期5卷 463-465页

作者：赵伟黄永箴 State Key Laboratory on Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences

Square microcavity laser with an output waveguide is proposed and analyzed by the finite-difference time-domain （FDTD） technique. For a square resonator with refractive index of 3.2, side length of 4μm, and output waveguide of 0.4μm width, we have got the quality factors （Q factors） of 6.7 ×10^2 and 7.3 × 10^3 for the fundamental and first-order transverse magnetic （TM） mode near the wavelength of 1.5μm, respectively. The simulated intensity distribution for the first-order TM mode shows that the coupling efficiency in the waveguide reaches 53%. The numerical simulation shows that the first-order transverse modes have fairly high Q factor and high coupling efficiency to the output waveguide. Therefore the square resonator with an output waveguide is a promising candidate to realize single-mode directional emission microcavity lasers.

关键词： Computer simulation finite difference time domain method Laser modes Light emission Refractive index

Double-notch-shaped microdisk resonator devices with gapless coupling on a silicon chip

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Chinese Optics Letters 2009年第4期7卷 296-298页

作者：罗贤树潘永安 Photonic Device Laboratory Department of Electronic and Computer EngineeringThe Hong Kong University of Science and Technology

We propose novel double-notch-shaped microdisk resonator-based devices with gapless waveguide-to- microdisk and inter-cavity coupling via the two notches of the microdisk. Both finite-difference time- domain simulations and experimental demonstrations reveal the high-quality-factor multimode resonances in such microdisks. Using such double-notch mierodisk resonators, we experimentally demonstrate the many-element linearly cascaded-microdisk resonator devices with up to 50 elements on a silicon chip.

关键词： finite difference time domain method time domain analysis

Positive-negative birefraction phenomenon for TM polarization in annular photonic crystal

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Chinese Optics Letters 2011年第2期9卷 69-72页

作者：张园沈义峰周杰王永春吴芳芳孙建郭昌清 Physics Department of the Science College China University of Mining and Technology Surface Physics Laboratory Fudan University

We propose a two-dimensional （2D） annular photonic crystal （APC） with dual equi-frequency contours （EFCs） in one band. The refractive behaviors of a Gaussian beam incident from air to the APC are analyzed by the EFC analysis and finite-diflerence time-domain （FDTD） method. The results show the positive-negative birefraction phenomenon for the transverse magnetic （TM） polarization in the same band occurs at the interface between air and the APC, and the surface termination of the APC has a large effect on the strength of the negatively refracted beam.

关键词： finite difference time domain method Photonic crystals Polarization

Modeling bidirectional reflection distribution function of microscale random rough surfaces

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Journal of Central South University 2010年第2期17卷 228-234页

作者：王爱华 HSU P.F. 蔡九菊 School of Materials and Metallurgy Northeastern University Department of Mechanical and Aerospace Engineering Florida Institute of Technology

The radiative properties of three different materials surfaces with one-dimensional microscale random roughness were obtained with the finite difference time domain method(FDTD) and near-to-far-field *** surface height conforms to the Gaussian probability density function *** computational modeling issues that affect the accuracy of the predicted properties were *** results show that,for perfect electric conductor(PEC) surfaces,as the surface roughness increases,the magnitude of the spike reduces and eventually the spike disappears,and also as the ratio of root mean square roughness to the surface correlation distance increases,the retroreflection becomes *** predicted values of FDTD solutions are in good agreement with the ray tracing and integral equation *** overall trend of bidirectional reflection distribution function(BRDF) of PEC surfaces and silicon surfaces is the same,but the silicon's is much less than the former'*** BRDF difference from two polarization modes for the gold surfaces is little for smaller wavelength,but it is much larger for the longer wavelength and the FDTD simulation results agree well with the measured *** terms of PEC surfaces,as the incident angle increases,the reflectivity becomes more specular.

关键词： bidirectional reflection distribution fimction random rough surfaces Maxwell equations finite difference time domain method

Compact triplexer in two-dimensional hexagonal lattice photonic crystals

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Chinese Optics Letters 2011年第4期9卷 87-90页

作者：任宏亮马建平温浩覃亚丽吴哲夫胡卫生姜淳金耀辉 College of Information Engineering Zhejiang University of Technology College of Computer Science and Technology Zhejiang University of Technology State Key Laboratory of Advanced Optical Communication Systems and Networks Shanghai Jiao Tong University

We design a compact triplexer based on two-dimensional （2D） hexagonal lattice photonic crystals （PCs）. A folded directional coupler （FDC） is introduced in the triplexer beside the point-defect micro-cavities and line-defect waveguides. Because of the reflection feedback of the FDC, high channel drop efficiency can be realized and a compact size with the order of micrometers can be maintained. The proposed device is analyzed using the plane wave expansion method, and its transmission characteristics are calculated using the finite-difference time-domain method. The footprint of the triplexer is about 12 9 μm, and its extinction ratios are less than -20 dB for 1310 nm, approximately -20 dB for 1490 nm, and under -40 dB for 1550 nm, making it a potentially essential device in future fiber-to-the-home networks.

关键词： Crystal lattices Defects Fiber optic networks finite difference time domain method Multiplexing equipment Optical waveguides Personal communication systems time domain analysis Two dimensional

High speed sub-micrometric microscopy using optical polymer microlens

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Chinese Optics Letters 2009年第10期7卷 901-903页

作者：曾新华 J.Plain S.Jradi P.Renaud Goud R.Deturche P.Royer R.Bachelot Laboratoire de Nanotechnologie et d'Instrumentation Optique ICD CNRS FRE 2848Universit de technologie de Troyes Department of Physics Shanghai Jiao Tong University

We report the high speed scanning submicronic microscopy （SSM） using a low cost polymer microlens integrated at the extremity of an optical fiber. These microlenses are fabricated by a free-radical photopolymerization method. Using a polymer microlens with a radius of curvature of 250 nm, a sub-micrometric gold pattern is imaged experimentally by SSM. Different distances between the tip and the sample are used with a high scanning speed of 200 cm/s. In particular, metallic absorption contrasts are described with an optical spatial resolution of 250 nm at the wavelength of 532 nm. Moreover, finite-difference time-domain （FDTD） simulations concerning the focal lengths of microlenses with different geometries and heights support the experimental data.

关键词： finite difference time domain method Microlenses Optical fiber fabrication Optical fibers Polymers