The progressive miniaturization and realization of more complex geometrical devices are challenging tasks for micro- and nanomanufacturing technologies. Laser direct writing by two-photon polymerization (2PP) is one of the most important and promising approaches for the fabrication of high resolution 2D and 3D microand nanostructures. In this respect, this dissertation is devoted to the investigation and application of 2PP for the realization of specially designed optical structures. One focus of this dissertation is on the fabrication of periodic structures with gap sizes and feature sizes below the optical diffraction limit. And various specially designed 3D structures with complex geometries achieved by 2PP are also demonstrated. Another focus is on the optical characterization of the fabricated 2D and 3D microdevices. The characterization is mainly performed by leakage radiation microscopy, which is a popular tool for the excitation and observation of surface plasmon polaritons (SPPs). Furthermore, special 2D metallic structures fabricated using a technique called microscope projection photolithography are also developed for the investigation of SPPs propagation behaviors.weiterlesen