Enhancing the sensitivity of a single electron spin sensor by multi-frequency control

Abstract

The negatively charged nitrogen vacancy (NV) center in diamond is increasingly attractive as a solid-state quantum sensor with high sensitivity and spatial resolution. However, the host non-zero nitrogen nuclear spin of the NV center decreases the signal contrast and sensitivity because of hyperfine coupling. Here, we apply multi-frequency synchronous manipulation to the NV center to recover the signal contrast and enhance the sensitivity. The enhancement effect works over a wide range of bias magnetic fields. Compared to the single-frequency-driven sensing process, a sensitivity enhancement factor of 2.7 is achieved at a low bias magnetic field. Such multi-frequency-controlled sensitivity enhancement works also for sensing temperature, strain, and electric field and can be applied to other spin–spin coupling systems.