Quantum Sensing with Defects in Diamond and Semiconductors*

Quantum sensing is a paradigm shift, relying on the intrinsic sensitivities of quantum state to their surrounding environment to detect extremely small changes in temperature, magnetic, and electric fields. The success of quantum sensing using nitrogen-vacancy (NV) defects in diamond under ambient conditions has sparked a growing interest in discovering other solid-state defects in wide bandgap semiconductors with comparable properties. Defects as qubit platforms, are highly susceptible to various sources of noise from experimental setup hardware and external factors, such as fluctuations in excitation lasers, unwanted sample heating caused by laser excitation and microwave drives, and impurities in the sample. To mitigate the effects of these experimental artifacts, we employed hardware improvements and better data processing techniques in our measurements. We utilized machine learning (ML) algorithms which not only increased the fidelity of our data but also dramatically increased the sensitivity in our measurements. We have developed methods for the fabrication of high efficiency microstrip and coplanar RF antennas, which removed the need for the use of an RF amplifier in optically detected magnetic resonance (ODMR) based quantum sensing of magnetic fields. In this talk, our recent results on the characterization of defects in 3C and 4H SiC, cubic boron nitride, 2D transition metal dichalcogenides (TMDs) for quantum sensing applications will be presented. Exciton dynamics in 2D TMDs will be discussed. Our recent achievements in miniaturization of NV diamond based quantum sensor devices will be also covered.