基于Au-TiO_(2)涂层凹槽的D形光子晶体光纤的等离激元红外传感器设计

Design of Plasmonic Infrared Sensor Based on D-Shaped Photonic Crystal Fiber with Au-TiO_(2) Coating Grooves

设计了一种基于D形光子晶体光纤(PCF)的新型等离激元传感器,用于检测低折射率的微小变化,并通过有限元法(FEM)对其性能进行了数值分析。与传统D形PCF不同,本文提出在D形光纤截面处刻蚀C型凹槽通道,并涂覆Au层来激发等离激元。C形凹槽通道的设计可以增强纤芯的能量泄露以及光纤芯模和等离子体模的耦合强度。在Au层上方增覆一层TiO_(2)介电层,可以增强对金属层的保护和提高传感器的灵敏度,将PCF表面等离谐振(PCF-SPR)传感器的工作波长范围扩展到红外区域,仿真结果得到的最大灵敏度为24236 nm/RIU。该传感器可以有效监测低折射率的微小变化,对于生物医学和有机检测及相关应用具有潜在的价值。

A novel plasmonic sensor based on a D-shaped photonic crystal fiber(PCF)is designed to detect low refractive index changes,and its performance is numerically analyzed using the finite element method(FEM).Unlike the traditional D-shaped PCF,this paper proposes that etching a C-shaped groove channel at the cross-section of the D-shaped fiber and coating the Au layer to excite the plasmons.The design of the C-shaped groove channel can enhance the energy leakage of the fiber core and the coupling strength of both the fiber core and the plasmonic modes.A TiO_(2) dielectric layer is added on top of the Au layer to enhance the protection of the metal layer and improve the sensitivity of the sensor.The operating wavelength range of the PCF surface plasmon resonance(PCF-SPR)sensor is extended to the infrared region.The maximum sensitivity obtained from the simulation results is 24236 nm/RIU.The sensor can effectively monitor small changes in a low refractive index and has potential value for biomedical and organic detection and related applications.