Enhancing quantum sensing performance by optimizing the concentration and dephasing time of the NV ensemble in CVD-diamond

• Published in: Optical materials express Vol. 13; no. 2; p. 393
• Main Authors: Wang, Sixian, Bian, Guodong, Fan, Pengcheng, Li, Mingxin, Li, Bo, Yuan, Heng
• Format: Journal Article
• Language: English
• Published: Washington Optical Society of America 01.02.2023
• Subjects: Diamonds; Electron irradiation; Nitrogen; Radiation dosage; Sensitivity; Sensors; Signal to noise ratio
• ISSN: 2159-3930; 2159-3930
• DOI: 10.1364/OME.478924

The negatively charged nitrogen−vacancy (NV − ) center ensembles in diamonds offer enormous potential for developing integrated sensors with an improved signal-to-noise ratio (SNR) and high sensitivity. However, the preparation and treatment of diamond samples with suitable NV − concentrations and dephasing time have remained challenging. This work provided insight into the NV − center formation mechanism and reconstruction via a comprehensive analysis of the concentration and dephasing time of a set of diamond samples treated by various parameters. By varying the electron irradiation dose and subsequent annealing duration, the conversion rate of nitrogen to NV − is up to 18.45%, and the corresponding maximum NV − concentration is 3.69 ppm. The dephasing time for all samples varies around 300 ns. The nitrogen-related NV − center ensemble dephasing rate per unit density is 146.4 (ppm·ms) −1 , indicating that the treatment did not substantially alter the paramagnetic spin environment around the NV − center. This study not only offers support to exquisite sensitivities of NV-based sensors but also provides valuable experience for the preparation of unique properties of synthetic diamonds.