基于表面等离子体共振和定向耦合的D形光子晶体光纤折射率和温度传感器  

D-shaped photonic crystal fiber refractive index and temperature sensor based on surface plasmon resonance and directional coupling

作　　者：施伟华[1] 尤承杰 吴静[1] 

机构地区：[1]南京邮电大学光电工程学院,南京210023

出　　处：《物理学报》2015年第22期278-283,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61275067)资助的课题~~

摘　　要：利用光子晶体光纤结构的灵活性和性能的优越性,设计了一种基于D形光子晶体光纤的折射率和温度传感器.在D形光子晶体光纤表面抛磨并镀上金纳米薄膜,作为表面等离子体共振传感通道用来测量液体折射率;在包层的一个空气孔中填充温敏液体甲苯,作为定向耦合通道实现对温度的测量.进一步的数值计算发现,基于定向耦合效应的温度传感和基于表面等离子体共振的折射率传感相互独立,D形光子晶体光纤同时进行折射率和温度传感检测.在各向异性的完美匹配层边界条件下利用全矢量有限元法对该传感器特性进行了数值研究,发现D形光子晶体光纤的空气孔直径决定了定向耦合吸收峰的中心波长和温度传感的灵敏度,金薄膜的厚度和D形结构的抛磨深度仅影响表面等离子体共振峰的相对强度.结果表明:该传感器在-10—80℃的温度范围内具有11.6 nm/℃的温度灵敏度,在1.34—1.44折射率范围内折射率灵敏度最高可达26000 nm/RIU.The photonic crystal fiber has received the widespread attention in the sensing field because of its flexible structure and unique features. A refractive index and temperature sensor based on the D-shaped photonic crystal fiber is designed and analyzed. In the side section of the D-shaped photonic crystal fiber, a coat with a gold film is used as a surface plasmon resonance （SPR） sensing channel for measuring the refractive index of liquid determinand. Temperature sensitive liquid-toluene is filled in an air hole A as a directional coupling sensing channel to realize the temperature measurement. When the SPR mode and guided mode satisfy the phase matching condition, the SPR effect is produced. Most of the core energy is transferred to the metal film layer in the surface, and then the.loss of guided mode in the fiber core will grow. Therefore, the shift of the SPR peak position can be used to measure the refractive index of the determinand indirectly. When the wave mode in the thermosensitive liquid-toluene can achieve phase matching with the guided mode, the directional coupling effect occurs, and then the wavelength of the absorption peak position can be used to measure the change of temperature indirectly. Based on further numerical simulation, the peak position of directional coupling is not changed by the refractive index of the determinand, and the SPR peak position is not shifted by the temperature change either. As these two sensing mechanisms can be distinguished easily, the refractive index and temperature sensing are simultaneously realized. The characteristics of the sensor are simulated numerically by using a full vector finite element method under the boundary condition of anisotropic perfectly matched layer. From the analysis of the D-shaped photonic crystal fiber structure parameters, we find that the diameter d of air hole plays an important role in the directional coupling absorption peak position and temperature sensitivity. For the SPR peak, its position is only affected by the thickness t

关 键 词：光子晶体光纤传感器 表面等离子体共振 定向耦合 双参量 

分 类 号：O734[理学—晶体学] TP212[自动化与计算机技术—检测技术与自动化装置]