Finite-difference Time-domain FDTD

Key words sUicon-on-insulator (SOI), sub-wavelength waveguide grating, grating mirror, finite-difference time-domain (FDTD), numerical simulations, CMOS... 

From preprint servers 319 Ward, D. W. Nelson, K. A. Finite Difference Time Domain (FDTD) Simulations of Electromagnetic Wave Propagation Using a Spreadsheet. 2004,arXiv physics/0402096.arXiv.org e-Print archive, http //arxiv.org/abs/physics/0402096 (accessed Oct 13,2004). 

Figure 4.1 Finite Difference Time Domain (FDTD) calculations of the local electric field around a Ag nanoprism with slightly rounded comers (100 nm edge length, 12 nm thick) both (A) on (508 mn) and (B) off (608 mn) resonance.

Since enhanced electromagnetic fields in proximity to metal nanoparticles are the basis for the increased system absorption, various computational methods are available to predict the extent of the net system absorption and therefore potentially model the relative increase in singlet oxygen generation from photosensitizers. " In comparison to traditional Mie theory, more accurate computational methods, such as discrete dipole approximation (DDA/ or finite difference time domain (FDTD) methods, are often implemented to more accurately approximate field distributions for larger particles with quadruple plasmon resonances, plasmon frequencies of silver nanoparticles, or non-spherical nanoparticles in complex media or arrangements. ... 

A consequence of the complex interplay of the dielectric and thermal properties with the imposed microwave field is that both Maxwell s equations and the Fourier heat equation are mathematically nonlinear (i.e., they are in general nonlinear partial differential equations). Although analytical solutions have been proposed under particular assumptions, most often microwave heating is modeled numerically via methods such as finite difference time domain (FDTD) techniques. Both the analytical and the numerical solutions presume that the numerical values of the dielectric constants and the thermal conductivity are known over the temperature, microstructural, and chemical composition range of interest, but it is rare in practice to have such complete databases on the pertinent material properties. 

W. Yu and R. Mittra, A new higher-order subgridding method for finite difference time domain (FDTD) algorithm, in Proc. IEEE Antennas Propag. Soc. Int. Symp., Atlanta, GA, Jun. 1998, vol. 1, pp. 608—611. 

Figure 1. Current Nanoscale Optofluidic Sensor Arrays, (a) 3D rendering of the NOSA device, (b) 3D rendering after association of the corresponding antibody to the antigen immobilized resonator, (c) Experimental data illustrating the successful detection of 45 pg/ml of anti-streptavidin antibody. The blue trace shows the initial baseline spectrum corresponding to Fig. la where the first resonator is immobilized with streptavidin. The red trace shows the test spectra after the association of anti-streptavidin. (d) Finite difference time domain (FDTD) simulation of the steady state electric field distribution within the 1-D photonic crystal resonator at the resonant wavelength, (e) SEM image demonstrating the two-dimensional multiplexing capability of the NOSA architecture.

In addition to the interaction between the electromagnetic wave and the materials, the heating effect of applicators is also an important issue in microwave sintering. This is simply because applicators are necessary to build the cavity resonators. Various methods, such as finite-difference time domain (FDTD) [61-63], finite element method (FEM) [64], transmission line matrix (TLM) [65, 66], method of moments (MOM), have been used for such purposes. 

Solving the master equation is sufficient to obtain an electromagnetic field at a certain position. For a multidimensional calculation of various symmetries, a numerical method should be applied. There are three methods to calculate photonic band structures the plane wave expansion method (PWM), Green s function expansion, and the finite difference time domain (FDTD) method. 

To further the quantitative understanding of the interplay between quenching and spontaneous emission modification and their respective distance dependence, Bian, Dunn, Xie and Leung ran numerical simulations of the experiments [25]. They employed a finite-difference time-domain (FDTD) model on a 2-D lattice, represented in Fig. 16. Results are displayed in Fig. 17 for horizontally and vertically oriented dipoles and for probe-sample gaps of 6 and 24 nm. The computed results show the reversal of lifetime behavior in going from small to large gaps for horizontal dipoles. 

Figure 16. Schematic for finite-difference, time-domain (FDTD) calculations of fluorescent molecule behavior in near-field microscopy. The aperture diameter is 96 nm. The calculation is performed on a two-dimensional 300 x 300 grid of 1.2 nm square cells. The arrangement of f,-, and H points are shown in the zoom-in inset. A horizontal point dipole is placed at the center of the cell with the four surrounding H. points driven sinusoidally in the simulation. Molecular emission characteristics are evaluated as a function of the lateral displacement d and the tip molecule gap h. Adapted from Ref. 25.

To verify this quadrupole-dipole transform mechanism brought about by shape-engineered nanostructures, we numerically calculated the surface charge distributions induced in the nanostructures and their associated far-field radiation based on a finite-difference time-domain (FDTD) electromagnetic simulator (Poyntingfor Optics, a product of Fujitsu, Japan). Figure 2.4a schematically represents the design... 

Three-Dimensional Vector Holograms in Photoreactive Anisotropic Media describes the principle of vector holography and investigates the optical characteristics of vector holograms recorded in a photoreactive anisotropic medium. Diffraction properties of the holograms recorded in a model medium, are characterised and the results are analyzed with the use of the finite-difference time-domain (FDTD) method. By comparing the experimental and calculated results, the authors elucidate the formation mechanism of the vector holograms. 

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