Acta Phys. -Chim. Sin. ›› 2022, Vol. 38 ›› Issue (12): 2108041.doi: 10.3866/PKU.WHXB202108041

Special Issue: Special Issue in Honor of the 120’s Anniversary of Academician Ying Fu

• ARTICLE • Previous Articles     Next Articles

Graphene Photonic Crystal Fiber-Based Fluid Sensor toward Distributed Environmental Monitoring

Nianze Shang1,2, Yi Cheng2,3, Shen Ao4, Gulimire Tuerdi4, Mengwen Li2, Xiaoyu Wang1, Hao Hong1, Zehui Li1, Xiaoyan Zhang4,*(), Wangyang Fu4,*(), Kaihui Liu1,5,*(), Zhongfan Liu2,3,*()   

  1. 1 State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
    2 Beijing Graphene Institute (BGI), Beijing 100095, China
    3 Center for Nanochemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
    4 School of Material Science and Engineering, Tsinghua University, Beijing 100084, China
    5 Frontiers Science Center for Nano-optoelectronics, Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
  • Received:2021-08-26 Accepted:2021-10-20 Published:2021-10-25
  • Contact: Xiaoyan Zhang,Wangyang Fu,Kaihui Liu,Zhongfan Liu E-mail:xyzhang@iccas.ac.cn;fwy2018@mail.tsinghua.edu.cn;khliu@pku.edu.cn;zfliu@pku.edu.cn
  • About author:Email: zfliu@pku.edu.cn (Z.L.)
    Email: khliu@pku.edu.cn (K.L.)
    Email: fwy2018@mail.tsinghua.edu.cn (W.F.)
    Email: xyzhang@iccas.ac.cn (X.Z.)
  • Supported by:
    the National Natural Science Foundation of China(52025023);the National Natural Science Foundation of China(51991342);the National Natural Science Foundation of China(52021006);the National Natural Science Foundation of China(11888101);the Key R & D Program of Guangdong Province(2020B010189001);the Key R & D Program of Guangdong Province(2019B010931001);the Key R & D Program of Guangdong Province(2018B030327001);the Strategic Priority Research Program of Chinese Academy of Sciences(XDB33000000);the Beijing Natural Science Foundation(JQ19004);the Pearl River Talent Recruitment Program of Guangdong Province(2019ZT08C321)

Abstract:

Compared to traditional sensor device arrays, optical fiber systems capable of wide-range detection are gradually emerging as strong candidates for distributed monitoring owing to their simplified structure. However, the working mechanism of optical fiber sensors limits their use to the detection of physical parameters such as refractive index and is an obstacle for the detection of small doses of molecules by optical fiber systems. Several researchers have focused on this aspect to endow sensitivity to these optical fibers for gas or liquid molecules. By deliberately destroying the fiber structure, strong interactions between the evanescent field of optical fibers and the target materials, such as microfibers, D-shaped fiber, etc. can be achieved. Assisted by the surface plasmon resonance techniques, such configurations can exhibit highly enhanced sensitivity to a change in the refractive index caused by gas or liquid molecules. Two-dimensional materials are an excellent candidate as coating materials due to their high specific surface area, which also guarantees a large sensing response and simultaneously minimizes any side effects by suppressing the propagating mode of optical fibers. However, owing to the obstacles in optical fiber engineering and device fabrication, the abovementioned functional 2D sensors are still limited to sample-scale fabrication, and their mass-production has not yet been realized. An all-fiber distributed sensing system with high single-spot sensitivity is still difficult to fabricate. Here, we propose a new configuration of a grid-distributed environmental optical fiber sensing by introducing low-pressure chemical vapor deposition (LPCVD)-grown graphene photonic crystal fiber (PCF) into the optical fiber sensing system. We successfully synthesized monolayer and/or bilayer graphene in the air holes of PCF. By fusing the graphene PCF (Gr-PCF) to a single mode optical fiber, we fabricated an all-optical-fiber sensing system. Preliminary experiments suggest that Gr-PCF can selectively detect NO2 gas at ppb-level and exhibit ionic sensitivity in liquids. The ability to detect NO2 gas is attributed to the graphene layer's interaction among light-mode and adsorbed molecules: adsorption-induced additional hole-doping caused a shift in the Fermi level of graphene and eventually modulated its light absorption, leading to changes in the light intensity signals. We believe that the sensor can be extended to other kinds of gases and liquids, considering the affinity of graphene toward various molecules. In view of practical optical sensors, our design is compatible with the time domain or wavelength domain multiplexing techniques of optical fiber communication systems. Because CVD-based synthesis can be used to realize mass production, the design proposed herein shall be one of the answers to the distributed optical fiber environmental sensors.

Key words: Graphene, Graphene photonic crystal fiber, Optical sensing, Gas sensor, Distributed sensing

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