Domain Decomposition Method for Maxwell's Equations: Scattering off Periodic Structures

We present a domain decomposition approach for the computation of the electromagnetic field within periodic structures. We use a Schwarz method with transparent boundary conditions at the interfaces of the domains. Transparent boundary conditions are approximated by the perfectly matched layer method (PML). To cope with Wood anomalies appearing in periodic structures an adaptive strategy to determine optimal PML parameters is developed. We focus on the application to typical EUV lithography line masks. Light propagation within the multi-layer stack of the EUV mask is treated analytically. This results in a drastic reduction of the computational costs and allows for the simulation of next generation lithography masks on a standard personal computer.Comment: 24 page

A FDTD model for the post-reception synthetic focusing surface penetrating radar with mine detecting applications

Surface penetrating radar (SPR) is extensively used in military, civil, geophysical and archaeological applications. There has been an increasing emphasis on the use of SPR in the identification of buried unexploded ordnance, such as anti-tank mines, antipersonnel mines etc., which can be metallic or plastic in nature. Mine detection methods can be classified as destructive or non-destructive. Non-destructive mine detection methods employ metal detectors, magnetometers, infrared sensors and SPR. However, neither the metal detector nor the magnetometer can differentiate a mine from metallic debris and the infrared sensor merely notes a difference in thermal conductivity. In most battle fields the soil is contaminated by large quantity of shrapnel, metal scraps and cartridge cases which will give a high false alarm rate in the identification process. In this scenario the SPR is a promising technique for identification of both metallic and plastic mines. The use of finite difference time domain (FDTD) model to analyse the SPR, which makes use of post-reception synthetic focusing (PRSF) techniques, is presented

Bound States in Sharply Bent Waveguides: Analytical and Experimental Approach

Quantum wires and electromagnetic waveguides possess common features since their physics is described by the same wave equation. We exploit this analogy to investigate experimentally with microwave waveguides and theoretically with the help of an effective potential approach the occurrence of bound states in sharply bent quantum wires. In particular, we compute the bound states, study the features of the transition from a bound to an unbound state caused by the variation of the bending angle and determine the critical bending angles at which such a transition takes place. The predictions are confirmed by calculations based on a conventional numerical method as well as experimental measurements of the spectra and electric field intensity distributions of electromagnetic waveguides

Direct and Inverse Computational Methods for Electromagnetic Scattering in Biological Diagnostics

Scattering theory has had a major roll in twentieth century mathematical physics. Mathematical modeling and algorithms of direct,- and inverse electromagnetic scattering formulation due to biological tissues are investigated. The algorithms are used for a model based illustration technique within the microwave range. A number of methods is given to solve the inverse electromagnetic scattering problem in which the nonlinear and ill-posed nature of the problem are acknowledged.Comment: 61 pages, 5 figure