The Simulation Of Different Kinds Imaging In The Near-field Optics

The concept of near-field microscopy was proposed in 1928 by E H Synge, and has greatly developed. Many kinds of near-field ~microscopes have been invented. Near-field Scanning Optical Microscopy (SNOM) and Photon Scanning Tunneling Microscope (PSTM) have become increasingly popular as a tool to study the local optical electromagnetic field close to the surface of devices from integrated optics / photonics. They have been demonstrated to break the diffraction limit of resolution and collect the optical response of the sample point by point. Because they have an optical fiber as the probe in order to detect the surface evanescent wave and transform it to propagating wave, but have the different incident wave, so the different imaging systems. They both can detect the sample without damaging it, study live biological spectrum, and have found wide spread application. The direct numerical integration of full vector Maxwell equations in three dimensions finite-difference time-domain (FDTD) method was suggested as a numerical solution of electrodynamic problems.This thesis is based upon the rationale of near-field microscopy, applying the numerical simulation of the FDTD method On the two kinds of imaging systems, and discussing their characteristics. Firstly, in the situation with no tip in the system, the clear images can be shown easily, and there are the samples' interferences only. Then getting the different kinds of tips in the systems, the imaging become complex, and hard to explain. Furthermore, the influences of the imaging in both systems are investigated and compared. These results we got are valuable for the selection of the imaging system of the microscope.