Project Title: Numerical Simulation in Nearfield Optics

Summary:

Nearfield optics is an interesting branch of nano science. One of the promising instruments in nearfield optics is the Scanning Nearfield Optical Microscope (SNOM). The SNOM allows to optically observe objects that are considerably smaller than the wavelength. This is possible because the electromagnetic field can be concentrated in an area that is considerably smaller than the wavelength. This is well known in high voltage technology and other branches of electrical engineering but the design and fabrication of optical structures with an extremely localized field is very difficult. At the same time, the numerical simulation of such structures is very difficult because one has to model parts that are small compared with the wavelength as well as large parts. I.e., a code is required that can handle small and large parts at the same time. In a first step we considered 2D models of SNOM tips with objects at different positions near the tip. An attempt with a FDTD code did not lead to useful results within two months but the results with our MMP code were very encouraging. It seems that MMP is superior to FDTD and MoM codes for SNOM and other problems of nearfield optics. Therefore, we started considering 3D SNOM models with MMP. Although some results have been obtained, severe problems have been observed. These problems mainly are caused by infinite boundaries in the model of the substrate. In order to solve these problems, we are implementing new 'multidomain' basis functions in the code.

Contacts: Ch.Hafner, L. Novotny, IFH, ETZG95, ETH Zentrum, CH-8092 Zurich

Electronic Contacts: hafner@ifh.ee.ethz.ch

Index Terms: Numerical Simulation, Nearfield Optics, SNOM

In collaboration with: IBM Rueschlikon