[14p-D221-1~16] 6.2 Carbon-based thin films

△ [14p-D221-7] Experimental and theoretical analysis of noise strength and environmental correlation time of ensembles of nitrogen vacancy centers in diamond

〇Kan Hayashi¹, Yuichiro Matsuzaki², Takaki Ashida¹, Shinobu Onoda³, Hiroshi Abe³, Takeshi Ohshima³, Hatano Mutsuko⁴, Takashi Taniguchi⁵, Hiroki Morishita¹, Masanori Fujiwara¹, Norikazu Mizuochi¹ (1.Kyoto Univ., 2.AIST, 3.QST, 4.Tokyo Tech., 5.NIMS)

Keywords:NV center, the environmental noise

NV centers in diamond has been considered as an important building block for the realization of quantum information processing such as quantum simulation, and quantum metrology. Importantly, NV centers suffer from decoherence, which is an obstacle for more practical applications. There are many ways to suppress decoherence, such as the quantum Zeno effect, dynamical decoupling. However, the efficiency of these protocols strongly depends on the noise properties. So it is essential to understand how the nitrogen concentration affects decoherence, which will let us determine a strategy to improve the coherence time.Here, we report experimental and theoretical investigation of Hahn echo decay curves for NV centers in several diamond samples with different spin concentrations (the sum of NV and P1 concentration). Our experimental results show that an exponential decay curve is observed for a high nitrogen concentration and a non-exponential decay curve is observed for a low nitrogen concentration. Our analysis also shows that the correlation time and amplitude of the dipole interaction from the environmental spin bath have a linear dependence on the spin concentration.