"Nano-optical investigations using plasmonic resonances have revolutionized optics in the last few years. The ability to concentrate light in subwavelength dimensions and to locally enhance the strength of the electromagnetic field in a tailored fashion opened several new fields in materials research, such as tailoring the linear and nonlinear properties of optical materials at will. So-called metamaterials allow now to design and realize unprecedented optical properties on the submicrometer level and hence tailor dispersion as well as real and imaginary parts of the linear and nonlinear refractive indices as a function of wavelength and wavevector.Our ability to create two- and three-dimensional nanostructures with advanced fabrication technologies have led to the new era of complex plasmonics. We are able to tailor the spectral response of complex metallic nanostructures, including the creation of very sharp and narrow resonances. In combination with strong field localization and hence large dependence on the material properties of the nanostructure geometry and its surrounding, unique sensors with sensitivities close to fundamental limits should be within reach.In my proposal, I would like to explore the ultimate limits of light-matter interaction using complex plasmonic nanostructures. I would like to apply them to different physical, chemical, and biological situations and undertake the first steps from fundamental insight into first applications. Namely, I would like to investigate complex plasmonics in four different contexts: single molecule reactions on complex surfaces, antenna-enhanced structural analysis of large single molecules, such as proteins, motion sensing of conformational changes of single molecules, as well as chiral sensing down to the single molecule level, hence ultimately being able to distinguish a single D-glucose molecule from its L-glucose enantiomer. This would bridge the gap between nanophysics, chemistry, and biology."