Spectroscopy is a powerful tool in many physical settings, with applications ranging from analysis of basic physical properties to sample analysis in chemistry, material science and bio-imaging. This project aims at translating the powerful techniques used in spectroscopy to a novel type of sensors, based on the quantum properties of defects in diamond. These optically active defects (color centers) have an associated electronic spin that is sensitive to magnetic and electric fields, temperature, pressure, etc. The project will develop spectroscopic techniques, tailored to the quantum realm, that can be implemented with these nanoscale sensors in diamond. In particular, the project will focus on achieving noise spectroscopy, that is, measuring spatial and temporal correlation of random fields (in particular magnetic fields), which are ubiquitous in materials and biological sciences. By combining novel noise spectroscopic techniques that work for quantum sensors, with the nanoscale resolution of the quantum sensors themselves, the novel quantum noise spectroscopy technique will be able to measure fields at scales not previously accessible. In addition, the project will provide opportunities for training graduate and undergraduate students in broad areas, ranging from magnetic resonance, to quantum information, as well as experimental skills in electronics and quantum optics. The project will in addition develop outreach activities, including a diamond sensor demo.
advent of novel nanoscale sensors exploiting individual quantum systems promise to shed light into our fundamental understanding of nano-electronics, photonics and magnetics devices, and their underlying physical phenomena. These novel quantum probes, such as the Nitrogen-Vacancy center in diamond, can perform in conditions and with a spatial resolution previously inaccessible: they can be brought very close to the system of interest and measure minute magnetic (or electric) fields with nanoscale resolution. After the first proof-of-principle demonstrations in recent years, these sensors are on the verge of becoming transformative tools for the exploration of electromagnetic devices and materials. To reach this goal, these spin sensors should be able not only to measure the magnitude of a given field, but more importantly its temporal and spatial correlations that carry most of the information about underlying physical properties. The goal of this project is to transform quantum sensors associated with spins in diamond into powerful spectrometers, able to detect spatiotemporal correlations of magnetic fields at the nanoscale due to, e.g., biological or magnetic materials dynamics, with a spatial resolution and sensitivity previously unattainable. Moreover, characterizing the noise spectrum is critical for devising effective strategies to counteract decoherence in emerging quantum devices. This project will combine expertise on noise spectroscopy and on quantum digital filtering to achieve an efficient and complete reconstruction of the noise spectrum via a quantum nanoscale sensor. The ultimate goal is to develop a new field of quantum digital noise spectroscopy, based on noise spectroscopy combined with the complete basis of Walsh digital filtering functions, and applying it to enhanced sensing of magnetic samples, and their structure and spatiotemporal correlations. Quantum digital noise spectroscopy with NV centers in diamond, also combined with super-resolution addressing of NVs, will be applied to nanoscale magnetic resonance imaging of biological samples and to measure spatial noise correlations of magnetic 2D materials. Such experiments could shed new light on the structure and dynamics of the measured samples, leading to new insights in biological functions and in universal properties of magnetic phase transitions.