Patrick Maletinsky
Quantum sensing using single spins in diamond nano-devices
University of Basel
Quantum systems can be used to detect and measure a broad range of physical quantities with sensitivities which are ultimately limited by quantum mechanics only. Such “quantum sensors” can significantly surpass the performance of their classical counterparts and thereby have the potential to become of utmost importance in science and technology. In recent years, the electronic spin system of the Nitrogen-Vacancy (NV) center in diamond has been established as a particularly attractive candidate for nanoscale quantum sensing of quantities such as magnetic fields, lattice strain or temperature. However, employing NVs for practical applications with direct technological or scientific impact requires the development of highly coherent, robust and efficient NV quantum sensors.
In this talk, I will discuss my group’s efforts to yield such high performance quantum sensors in order to apply them to outstanding problems in condensed-matter and mesoscopic physics. For robustness and efficiency in sensing, we employ single-crystalline diamond nanostructures, which we obtain through unique diamond nanofabrication processes that we have developed in the past. To highlight the performance of our approach and of these devices, I will present two lines of experiments in quantum sensing, which we currently explore. On one hand, we employ individual NV centers in all-diamond scanning probes for scanning NV magnetometry. Our devices yield nanoscale spatial resolution and excellent magnetic field sensitivities, which we exploit to locally study nano-magnetic phenomena. I will present examples such as domain wall imaging in thin magnetic films or our efforts to locally study collective spin-excitations in nanoscale magnetic objects. On the other hand, we investigate hybrid systems formed by NV centers embedded in diamond nanomechanical resonators. There, spins and oscillators are coupled by a novel mechanism based on crystal strain. This coupling is strong and could in the future yield precise accelerometers or allow for quantum state transfer between spin and oscillator - a longstanding goal in the field of hybrid mechanical systems. I will present recent results, where we exploit this coupling to strongly and coherently drive the NV spin and thereby protect it from environmental decoherence. This novel method for continuous dynamical decoupling significantly increases NV spin coherence times and could therefore yield even more powerful NV based quantum sensors in the future.