Nonclassical states of light are a major tool for photonic quantum technologies. The Experimental Solid State Quantum Optics group investigates approaches to generate and characterize such states. Moreover, we exploit them for novel quantum sensing approaches like the »spooky« quantum imaging with undetected light. Within waveguide lattices quantum states of light perform quantum walks, which can be utilized for quantum simulation or for studying fundamental concepts of quantum physics as for instance non-Hermitian quantum systems.