The interaction between light and matter is usually limited by the size mismatch between light wavelength and molecular size in the matter. Well-engineered nanostructures offer unique opportunities to enhance and sculpt the optical field at nanoscale and thereby to improve and control light-matter interactions. Based on fundamental knowledge in physics and chemistry we perform theoretical design with modern computer simulations and exploit the state-of-the-art nanotechnologies to realize high-definition novel nanostructures. Linear and nonlinear microscopic and spectroscopic methods are used to characterize the optical response of the nanostructures. Final functional nanostructures tailored for specific applications are then brought to real applications or utilized to address the fundamental questions in different research fields. The goal of the Nanooptik Research Group is to understand, control and utilize nanoscale light-matter interactions through the application of rationally designed nanostructures.