Quantum sensors are the most sensitive measurement devices achieving record precision in measuring time, magnetic, electric or gravitational fields. However, their function usually relies on dedicated environmental conditions restricting their application and up until recently they were not compatible with nanoscale spatial resolution. However, novel quantum spin sensors, particularly those based on defects in diamond, promise to achieve both goals.
At the CeQT, we develop unique new tools for applications in quantum technology, material science and bio-/medical analytics based on such a quantum nanosensor. Besides other approaches, one of the main workhorses is a hybrid quantum structure consisting of a diamond photonic nanostructure hosting a single color center. A conically-tapered nanopillar monolithically fabricated on a diamond cantilever serves as a waveguide for efficient optical excitation and fluorescence photon collection of a single nitrogen-vacancy center located at its extremity. When mounted to a tuning fork, this architecture forms a robust platform for NV-based scanning probe magnetometry applications.