Continuous-Wave ODMR in Diamond NV Centers_ Principles and Magnetic Field Effects

Ryohei Dokai, Ryusei Okaniwa, Miku Ishizaki +2 more

The nitrogen-vacancy (NV) center in diamond has attracted considerable attention as a highly sensitive quantum sensor that can operate at room temperature. In particular, continuous-wave optically detected magnetic resonance (CW-ODMR) is promising for a wide range of applications because of its simplicity. However, conventional AC magnetic-field sensing schemes based on CW-ODMR suffer from a limited detection bandwidth: the detectable frequency is either fixed by intrinsic physical parameters of the NV center or, even when tunable, restricted to a narrow range of only a few MHz. Here, we propose a broadband AC magnetometry scheme based on CW-ODMR with NV centers using microwave-driven dressed states.Through theoretical analysis and numerical simulations, we show that the proposed scheme enables the detection of AC magnetic fields with frequencies up to the order of 100 MHz, which has been difficult to achieve using conventional CW-ODMR-based methods.

V. P. Popov, Sergey N. Podlesny, Valentin A. Antonov +2 more

Akira Watanabe, Tetsuri Nishikawa, Hiromitsu Kato +4 more

Hiroshige Deguchi, Tsukasa Hayashi, Hiroya Saito +6 more

Abstract We developed a compact, portable quantum sensor module for pulsed measurements using diamond nitrogen-vacancy (NV) centers, an excitation laser diode of 3 mW and a microwave source of 15 dBm. This module allowed the evaluation of ensemble diamond NV centers for measuring magnetic fields by continuous wave— optically detected magnetic resonance (ODMR), Rabi oscillation, pulsed ODMR, Ramsey measurement and spin-echo measurement. The sensitivity through pulsed measurements reached 40 nT/ Hz at 1 Hz, which achieved higher sensitivity by one order, especially at a frequency around 1 Hz compared with previously reported compact modules using diamond NV centers.

Ryusei Okaniwa, Takumi Mikawa, Yuichiro Matsuzaki +8 more

The nitrogen-vacancy (NV) center is a promising candidate to realize practical quantum sensors with high sensitivity and high spatial resolution at room temperature and atmospheric pressure. In conventional high-frequency AC magnetometry with NV centers, the setup requires a pulse sequence with an appropriate time synchronization and strong microwave power. To avoid these practical difficulties, AC magnetometry using continuous-wave optically detected magnetic resonance (CW-ODMR) was recently demonstrated. That previous study utilized radio frequency (RF)-dressed states generated by the coherent interaction between the electron spin of the NV center and the RF wave. However, the drawback of this method is that the detectable frequency of the AC magnetic fields is fixed. Here, we propose and demonstrate frequency-tunable magnetic field sensing based on CW-ODMR. In the new sensing scheme, we obtain RF double-dressed states by irradiation with RF fields at two different frequencies. One creates the RF-dressed states and changes the frequency of the target AC field. The other is a target AC field that induces a change in the CW-ODMR spectrum by generating the RF double-dressed states through coherent interaction with the RF-dressed states. The sensitivity of our method is estimated to be comparable to or even higher than that of the conventional method based on the RF field with a single frequency. The estimated bandwidth is 7.5 MHz, higher than that of the conventional method using the RF-dressed states. Our frequency-tunable magnetic field sensor based on CW-ODMR paves the way for new applications in diamond devices.

Jean-Christophe Jaskula, Alexei S. Trifonov, David R. Glenn +2 more