2025/04/11 by Rottstaedt, Yves, Lindner, Lukas, Schall, Florian +9 · 1 citation
#Applied Physics (physics.app-ph) #FOS: Physical sciences #Optics (physics.optics) #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.2504.08466
Nitrogen-vacancy (NV) centers in diamond are a promising platform for high-precision magnetometry. In contrast to the use of spontaneous emission in a number of NV-magnetometers, laser threshold magnetometry (LTM) exploits stimulated emission of NV centers by placing an NV-doped diamond inside an optical cavity. The NV laser system is predicted to reach a high magnetic-field-dependent contrast and coherent signal strength, leading to an improved magnetic field sensitivity combined with a high linearity. Here, we consider a two-media setup where the cavity additionally includes a vertical external cavity surface emitting laser. This optically active material compensates cavity losses at \SI750nm while still allowing for magnetic-field-dependent effects from the NV-diamond. We demonstrate a magnetic-field-dependent laser threshold and investigate the effects of pump laser induced absorption of the diamond. The experimental data is supported by an analytical simulation based on a rate model. Furthermore, we derive a generalized formula to compute the shot-noise-limited magnetic field sensitivity in the regime of high contrast yielding 49.07(33) pT/√(Hz) for the present setup. Simulations with an optimized NV-diamond suggest that values down to 4.9 ft/√(Hz) are possible.