Two-Photon Polymerization and application to Surface Plasmon Polaritons

Plasmonics is a large part of the field of nanophotonics. Besides a wide range of industrial applications already developed, e.g. enhanced biosensors and diodes, surface plasmon polaritons (SPPs) are still an expanding field of research. In conventional optics, working on the sub-wavelength scale is not trivial, and structures smaller than half the wavelength will not lead to results expected by traditional optics. State-of-the-art microchips and optical data storage devices are fabricated at the limit of conventional optics. SPPs could open up the way to sub-wavelength optics far beyond the diffraction limit as demonstrated by Ebbesen in 1998. The length scales for SPPs span over seven orders of magnitude, from several nanometers, the penetration depth into metal, to several centimeters, the propagation length of long range plasmons, making them very interesting objects for investigation. The subject of this thesis is the investigation on dielectric loaded surface plasmon polariton waveguides (DLSPPWs). DLSPPWs are theoretically analysed by computational simulations at telecommunication wavelength at 1550nm. The waveguides are experimentally examined using leakage radiation microscopy for 632nm and 800nm wavelength. The experimental results are compared with simulation results of corresponding wavelengths. Furthermore, SPP structures like bends and Y-splitters are investigated. A novel cut-splitter design for an SPP Y-splitter is introduced and compared to existing designs. For the cut-splitter an improved efficiency and a better tolerance against fabrication imperfections due to limited resolution than for conventional Y-splitter designs is demonstrated through experimental investigations and simulations. For the fabrication of DLSPPWs, 2-Photon Polymerization (2PP) is, because of its high flexibility and low costs compared to other nanostructuring technologies, and easy adaptability. Since the first publication about 2-Photon-Polymerization by S. Kawata in 1997, the interest and research in this technology has been continuously increasing. Progress in this technique has been mainly initiated by scientific interest for use as a rapid prototyping technology. To transfer the 2PP technology to industrial applications, a novel structuring system is developed and set up during this work. The 2PP writing speed is increased by a factor of about 100, compared to results in other publications. Three-dimensional structures with resolutions smaller than 300nm are reproducible fabricated with writing speeds of about 30mm/s.