All-fiber quantum relaxometry for biochemical sensing based on diamond NV centers

作者：Hongda Chen, Yunhan Luo, Xiaoling Luo, Xue Chen, Yuxin Li, Gui‐Shi Liu, Lei Chen, Zhe Chen, Yaofei Chen · 发表于：Optics Express · 年份：2024 · DOI：10.1364/oe.525407 · 被引用次数：9 · 研究领域：Diamond and Carbon-based Materials Research、Advanced Fiber Laser Technologies、Analytical Chemistry and Sensors

The longitudinal relaxation time (termed as T 1 ) of nitrogen-vacancy (NV) centers in nanodiamonds can be affected by surface electric or magnetic noise, which has been exploited to develop cutting-edge quantum relaxometry for biochemical sensing. In this work, a tiny all-fiber quantum probe based on longitudinal relaxometry was developed by chemically-anchoring nanodiamonds on the surface of a cone fiber tip. The dependences of T 1 on surface electric and magnetic noise were discussed in theories first and then experimentally demonstrated in varied pH and Gd 3+ concentration solutions, respectively. Because of NV centers being subject to enhanced coupling from surface noise, T 1 reduced from 290 to 245 µs when pH changed from 3 to 9 and reduced to 220 µs when Gd 3+ concentration increased to 10 mM, agreeing well with theoretical results. Based on these, the Gd 3+ -tagged-biotin and streptavidin model was designed and implemented on the all-fiber probe, and results demonstrated the detection of biotin with a limit of 168 nM and good specificity. This paper opens a new way to develop an all-fiber quantum probe by exploiting the unique electrical spin properties of NV centers, and the probe shows great potential for biological detection with high sensitivity and specificity.