Kilohertz electron paramagnetic resonance spectroscopy of single nitrogen centers at zero magnetic field

Abstract

Electron paramagnetic resonance (EPR) spectroscopy is among the most important analytical tools in physics, chemistry, and biology. The emergence of nitrogen-vacancy (NV) centers in diamond, serving as an atomic-sized magnetometer, has promoted this technique to single-spin level, even under ambient conditions. Despite the enormous progress in spatial resolution, the current megahertz spectral resolution is still insufficient to resolve key heterogeneous molecular information. A major challenge is the short coherence times of the sample electron spins. Here, we address this challenge by using a magnetic noise–insensitive transition between states of different symmetry. We demonstrate a 27-fold narrower spectrum of single substitutional nitrogen (P1) centers in diamond with a linewidth of several kilohertz, and then some weak couplings can be resolved. Those results show both spatial and spectral advances of NV center–based EPR and provide a route toward analytical (EPR) spectroscopy at the single-molecule level.

In situ electron paramagnetic resonance spectroscopy using single nanodiamond sensors

“…Moreover, even itself can be reduced to ~2 MHz if utilizing the noise-insensitive transitions 42 . We note that the fundamental limit maybe even better than this value if single ions can be detected 43 . By then, magnetic shielding or compensation will be required.…”

High sensitivity magnetic field sensing via a sandwich-type polydimethylsiloxane resonator

“… – 4 Compared with traditional electronic magnetometers, optical magnetic sensors have the advantages of good reliability, wide dynamic range, and strong anti-interference capability, such as atomic magnetometers, nitrogen-vacancy color center optical magnetic sensors, and whispering gallery mode (WGM) resonator-based optical magnetic sensors 5 – 11 In the last decade, optical magnetic sensors based on WGM resonator have a promising application in high sensitivity magnetic field detection since they have a high quality-factor (Q-factor) and compact mode volume, which can greatly increase the intensity of the optical field and material interaction inside the resonator.…”

CSRR Structure Design for NV Spin Manipulation with Microwave Strength and Fluorescence Collection Synchronous Enhancement

“…Compared with all-optical and electrical methods, which have the limitations of only being applied in a single NV center or being hard to employ for complex quantum state manipulation [ 6 , 7 , 8 ], the microwave method provides better precision in quantum state rotation. Quantum metrology with an NV combining quantum state manipulation through microwaves has achieved excellent sensitivity in the areas of nuclear magnetic resonance (NMR), as well as magnetic and electric sensing [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ].…”