Towards fieldable NVC quantum sensors for defense applications

The rapid progress in quantum sensing enables a number of defense and security related applications in the near future. Sensors based on Nitrogen-vacancy centers (NVC) in diamond provide a high technological potential, robustness, the capability of integration and room temperature operation. For magnetometry such sensors are already capable of measuring static magnetic fields with pT/√Hz accuracy at room temperature in conjunction with high spatial resolution. This technology is of particular interest for remote magnetometry with several defense use-cases. Positioning, Navigation and Timing (PNT) increasingly relies on global navigation satellite systems. NVC-based singlechip vector magnetometers can be utilized to generate global magnetic maps and afterwards use them for magnetic georeferencing for autonomous positioning and to enhance existing inertial navigation systems in GNSS-denied operations. The paper describes progress in key enabling technologies such as CVD diamond growth, NVC doping, diamond chip technology, sensor miniaturization, integration of readout electronics, sensor characterization and noise analysis. NVC can also be used for broadband RF signal analysis by utilizing the bias-field induced frequency shift of the ground state resonances. With known static magnetic field this allows to determine the frequency and amplitude of unknown RF signals. This technique is therefore suited for analysis of passively intercepted complex and agile RADAR and communication signals, i.e., for real-time signal analysis or electronic warfare (EW) applications. As an application the interception and analysis of frequency agile communication signals in real-time is demonstrated with a compact NVCbased RF sensor.