Research On Propagation Properties Of An Optical Surface Plasmonic Waveguide With A Bowtie Air Core

There is an undeniable and ever-increasing need for faster information processing and transporting.Many believe that the current electronic techniques are running out of steam due to issues with RC-delay times, meaning that fundamentally new approaches are needed to increase data processing and operating speeds. Due to the existence of the diffraction limit,today we are at a crossroads in this technology. In recent years, Surface Plasmons (SPs) is found to be beating the diffraction limit, so it is of interest to a wide spectrum of scientists, ranging from physicists, chemists and materials scientists to biologists. As development of nanotechnology, controlling SPP at nano-scale will be used at integrated optical circuit, optic data storage, microscopy and solar cells, as well as being used to construct sensors for detecting biologically interesting molecules.In this dissertation, the concept of surface Plasmon (and) surface plasmon polaritons are expounded firstly, the history of surface plasmonic waveguides and Key stage are discoursed, then the finite difference frequency domain (FDFD) method is introduced simply.The main content of this dissertation:A kind of surface plasmonic waveguide with a bowtie air core was designed in this article. The dependence of distribution of longitudinal energy flux density, effective index and propagation length of the fundamental mode supported by this waveguide on geometrical parameters and working wavelengths are analyzed using the finite-difference frequency-domain (FDFD) method. Results show that the longitudinal energy flux density distributes mainly in the center region which is formed by the top and the bottom ridge. The effective index, propagation length of the fundamental mode and the mode area can be adjusted by the geometric parameter as well as the working wavelength. At the certain working wavelength, the effective index decreases as the radius of ridge increases, meanwhile propagation length and mode area of the fundamental mode increase as radius of ridge increases. The geometric parameter radius of circles at four corners can effect propagation properties slightly. The radius of sectors on both sides can effect propagation properties obviously. With certain geometric parameters, relative to the case of the working wavelengths, in the case of larger working wavelengths, the area of field distribution is larger, and the size of the contact area of field and metallic surface is also larger, then the interaction of field and silver is weaker, and the effective index becomes smaller, so the propagation length becomes larger. The possibility of applicating of this kind of surface plasmonic waveguide to the field of sensor was discussed.These studies will provide new theoretical basis for the future practical application of photonic devices integration and sensor.