基于紫磷增敏的即插即用式双通道光纤表面等离激元共振折射率计

Violet phosphorus-enhanced plug-and-play double-lane fiber optic surface plasmon resonance refractometer

光纤表面等离激元共振(surface plasmon resonance,SPR)传感技术可以直接感测传感器周围分子相互作用导致的传感器表面折射率变化,具有体积小、成本低、免标记、灵敏度高,易实现小型化、多参量、实时原位检测等优势.本文基于新型二维纳米材料紫磷并结合完备的制备与表征工艺首先构建了两种探针式光纤SPR折射率计,可实现对面/体结合折射率的高灵敏度、即插即用式检测.在1.33-1.34低折射率范围内,本文设计的光纤/紫磷/金层/样品层近场增强型SPR折射率计灵敏度和品质因数最高分别达到2335.64 nm/RIU和24.15 RIU^(−1),分别是单金层SPR折射率计的1.31倍和1.25倍;所设计的光纤/金层/紫磷/样品层近导波型SPR折射率计灵敏度和品质因数分别达到2802.06 nm/RIU和22.53 RIU^(−1),是单金层SPR折射率计的1.57倍和1.16倍.最后,将近场增强型SPR和近导波型SPR集成到一个光纤探针中,实现了双通道传感.本文开发的探针式双通道光纤SPR折射率计为生化领域中多类型蛋白检测、重金属离子检测等提供了一种新思路.

The fiber optic surface plasmon resonance(SPR)technologies can directly detect the change of the refractive index on the surface of the sensor,caused by the interaction of biochemical molecules.Fiber optic SPR technologies have advantages of small size,low cost,no labeling,high sensitivity,and are easy to realize the miniaturization,multi-parameter,real-time and in-situ detection.Two types of probe-type fiber optic SPR refractometers are constructed based on the novel two-dimensional nanomaterial,i.e.,violet phosphorus(VP),the mature fabrication and characterization technologies.The fabrication processes of the fiber optic SPR refractometers are first introduced,and then the feasibility of the fabrication processes is verified via multiple characterization methods.In terms of the signal demodulation,the noise of the resonance spectrum is suppressed by the variational mode decomposition algorithm,and the resonance wavelength is interrogated and monitored in real time by the centroid method.The refractive index sensing performances of the near-field enhanced fiber optic SPR refractometers coated with different layers of VP are investigated.With the increase of the VP layer number,the resonance spectrum exhibits redshift and broadening and the sensitivity is enhanced.The refractive index sensing performance of the nearly guided wave fiber optic SPR refractometer is also investigated.In the low refractive index range of 1.33-1.34 corresponding to the refractive index of the low-concentration biological solution,the sensitivity and the figure of merit of the near-field enhanced fiber optic SPR refractometer with the sensing structure of fiber core/VP dielectric layer/Au layer/sample layer reach to 2335.64 nm/RIU and 24.15 RIU−1,respectively,which are 1.31 times and 1.25 times higher than the counterparts of the single Au layer fiber optic SPR refractometer,respectively.The sensitivity and the figure of merit of the nearly guided wave fiber optic SPR refractometer with the sensing structure of fiber core/Au layer/VP dielectric layer/sample layer can reach to 2802.06 nm/RIU and 22.53 RIU^(−1),respectively,which are 1.57 times and 1.16 times higher than the counterparts of the single Au layer fiber optic SPR refractometer.Finally,the near-field enhanced SPR and the nearly guided wave SPR are integrated into a single fiber probe to achieve the double-lane sensing.The fiber optic SPR refractometers developed in this study can realize the highsensitivity,plug-and-play and double-lane detection of the combination of surface refractive index and volume refractive index.The probe-type refractometer also provides a new idea for detecting multi-type protein molecules and heavy metal ions in the biochemical field.