Single Molecules for Applications in Quantum Sensing

Single molecules have started to attract attention for applications in quantum technologies. This is attributable to their similarities with defects in solids, such as the nitrogen vacancy (NV) center in diamond. These systems share properties such as photoluminescence, intersystem crossing, and ground state spin. However, defects in solids are confined to their host material, which limits the sensitivity by creating a separation between the sensor and sensing target. Alternatively, molecules can be deposited on or within a variety of materials; thereby offering the potential to minimize this distance and improve sensitivity. Additionally, molecules can be chemically modified using techniques from synthetic chemistry to enable improved affinity to sensing targets. In this poster, we present two molecular systems which have potential for applications in quantum sensing. First is vanadium phthalocyanine (VOPc) which has been shown to display electronic spin coherence times at room temperature approaching those of the NV center. The second are europium complexes, which possess unique optical and spin properties such as hypersensitivity to the local symmetry of the complex. We present optical characterization results from a single VOPc molecule quantum emitter as well as time resolved spectroscopy results for four different europium complexes and discuss potential directions for their use in quantum sensing.