Multi-channel few-mode multicore fiber based surface plasmon resonance biosensor with open air-hole
Multi-channel few-mode multicore fiber based surface plasmon resonance biosensor with open air-hole
复制标题
基于开放气孔的多通道少模多芯光纤表面等离子体共振生物传感器
DOI：
10.7498/aps.69.20200353
复制
发表时间：
2020-07-05
影响因子：
1
通讯作者：
Liu Tie-Gen
中科院分区：
文献类型：
--
作者：
Xiao Shi-Yan;Jia Da-Gong;Liu Tie-Gen
基于少模多芯光纤（FM-MCF）的结构特点，提出了一种开放空气孔的多通道FM-MCF表面等离子体共振（SPR）生物传感器。由于FM-MCF的空气孔分布，六个外部空气孔自然变成开放的空气孔，即通过化学蚀刻制造的凹槽感测通道。与D型结构、光纤锥形结构和光子晶体光纤空气孔结构相比，开口槽结构更容易容纳液态分析物。为了获得更好的传感性能，建立了带有敏感介质层的FM-MCF SPR生物传感器的传感模型，并采用有限元法进行了数值模拟。仿真中分析了芯孔间距、涂层厚度、传感器尺寸、光纤传输模式等因素对传感性能的影响以及多通道的作用。模拟结果表明，当空气孔与芯体相切（d = 0 p.m）时，FM-MCF SPR生物传感器具有较好的性能，因为芯体与孔体的距离d决定了倏逝波的泄漏强度。由于高阶模（LP Hax模）激发的倏逝场比基模（LP 01 x模）激发的倏逝场强，因此高阶模激发的SPR生物传感器性能优于基模激发的SPR生物传感器。当金、银和铟锡氧化物（ITO）的涂层厚度分别为40 nm、30 nm和100 nm时，损失光谱的半高宽达到最小值，表明该生物传感器在此意义上具有较好的性能。对于不同的传感波长，观察到金和银膜的谐振波长在可见光波长范围内，而ITO在近红外波长范围内。因此，我们的生物传感器可以在一个SPR透射光谱中同时检测多种液体分析物。此外，计算结果还表明，当其中一个槽道涂有100 nm ITO时，对于LP 11 ax模式，FM-MCF SPR生物传感器具有最高的灵敏度为20824.66 nm/RIU，折射率（RI）分辨率为4.8 × 10（-6）RIU，周围的RI从1.33变化到1.39，可检测牛血清白蛋白（BSA）溶液、人免疫球蛋白G和C反应蛋白的RI。此外，当我们的生物传感器的外槽通道涂有不同厚度的金、银和ITO膜时，可以单独检测多种生物液体分析物或联合检测同一种生物液体分析物，这揭示了槽传感通道的控制灵活性和检测分析物的多样性。
Based on the structural characteristics of the few-mode multicore fiber (FM-MCF), a multi-channel FM-MCF surface plasmon resonance (SPR) biosensor with open air-hole is presented. Due to the air-hole distribution of the FM-MCF, the six outer air-holes naturally become open air-holes, i.e. groove sensing channels, fabricated by chemical etching. Then, compared with D-shape structure, tapered structure of fiber and air-hole of photonic crystal fiber (PCF), the open groove structure is easy to accommodate the liquid analyte. In order to obtain better sensing performance, a sensing model of the presented FM-MCF SPR biosensor with sensitive dielectric layer is established and numerical simulations are performed using the finite element method. In the simulations, the effect of core-hole distance, coating thickness, sensing dielectrics, transmission modes in optical fiber on the sensing performance as well as the role of multi-channel are analyzed. The simulation results show that when the air-hole is tangent to the core (d = 0 p.m), the FM-MCF SPR biosensor has the better performance because the core-hole distance d determines the leakage intensity of the evanescent wave. As the evanescent field excited by high-order mode (LP Hax mode) is stronger than that by fundamental mode (LP01x mode), the performance of biosensors for SPR excitation by using high-order mode is better than by using fundamental mode. Meanwhile when the coating thickness of gold, silver and indium tin oxides (ITOs) is 40 nm, 30 nm and 100 nm respectively, the FWHM of loss spectrum reaches a minimum value, which means that the presented biosensor has the better performance in this sense. For the case of different sensing dielectrics, it is observed that the resonance wavelength of gold and silver film are in the visible wavelength range, while the ITO is at near-infrared wavelength. Then it is useful for our biosensor to simultaneously detect many liquid analytes in one SPR transmittance spectrum. In addition, the calculation results also show that when one of the groove channels is coated with 100 nm ITO for the LP11ax mode, the FM-MCF SPR biosensor has a highest sensitivity of 20824.66 nm/RIU and refractive index (RI) resolution is 4.8 x 10(-6) RIU with the surrounding RI changing from 1.33 to 1.39, in which the RI of bovine serum albumin (BSA) solution, human Immunoglobulin G and C-reactive protein can be detected. Moreover, when the outer groove channels of our biosensor are coated with gold, silver and ITO film with different thickness, many biological liquid analytes can be detected separately or the same biological liquid analyte can be detected jointly, which reveals that the control flexibility of the groove sensing channel and the diversity of the detection analytes.