Experimental and Theoretical Analysis of Noise Strength and Environmental Correlation Time for Ensembles of Nitrogen-Vacancy Centers in Diamond
Kan Hayashi, Yuichiro Matsuzaki, Takaki Ashida, Shinobu Onoda, Hiroshi Abe, Takeshi Ohshima, Mutsuko Hatano, Takashi Taniguchi, Hiroki Morishita, Masanori Fujiwara, Norikazu Mizuochi
Abstract
We experimentally and theoretically investigate the Hahn echo decay curve for nitrogen vacancy centers in diamond with different spin concentrations. The Hahn echo results show a non-exponential decay for low spin concentrations, while an exponential decay is dominant for high spin concentrations. By fitting the decay curve with a theoretical model, we show that both the amplitude and correlation time of the environmental noise have a clear dependence on the spin concentration. These results are essential for optimizing the NV center concentration in high-performance quantum devices, particularly quantum sensors.