金属膜衬底上亚波长介质光栅结构的特性及传感应用  

Characteristic of Subwavelength Dielectric Grating with Metal Layer and Its Sensing Applications

作　　者：马伟涛[1] 周骏[1] 黄水平[1] 苑红伟[2] 

机构地区：[1]宁波大学理学院,浙江宁波315211 [2]江苏大学机械工程学院,江苏镇江212013

出　　处：《中国激光》2011年第9期129-133,共5页Chinese Journal of Lasers

基　　金：国家自然科学基金(60977048);宁波市国际科技合作计划(2010D10018);宁波市自然科学基金(2009A610043)资助课题

摘　　要：提出亚波长介质光栅-金属膜-石英玻璃衬底结构,根据等效介质理论该结构可等效为由金属-光栅-包覆层构成的单面金属包覆波导,在入射波长和入射角满足一定条件时,发生导模共振(GMR)从而产生光波全吸收现象。根据严格耦合波分析(RCWA)理论进行数值分析发现,等效波导中的TM1 GMR峰尖锐,并且对光栅包覆层的折射率变化非常敏感,角度灵敏度为127.87°/RIU(RIU为折射率单位),波长灵敏度为409.35 nm/RIU,在很大的折射率范围内线性度良好。与全介质GMR传感器和光栅型表面等离子体共振(SPR)传感器相比,该结构通过GMR实现较高灵敏度的同时,其较窄的共振峰使得检测精度更高。The subwavelength dielectric grating-metal structure with a quartz glass substrate is proposed. It can be seen as a waveguide which is composed of metal layer, grating and superstrata according to the equivalent medium theory. With proper incident angles and light wavelengths, the total resonance absorption occurs. The resonance spectra of total absorption are analyzed using rigorous coupled-wave analysis （RCWA） method. The results show that the peak of TM1 mode of the waveguide is very sharp and sensitive to variation of refractivity of the superstrata. The angle sensitivity and wavelength sensitivity are 127.87° /RIU and 409.35 nm/RIU, respectively, and the linearity between the resonance peaks and the refractivity of superstrata is good in a large range of refractive index of superstrata. Compared with guide-mode sensors of all dielectric and grating-type surface plasmon resonance sensors, the proposed structure can realize high sensitivity and the narrow resonance peaks can provide high detection precision.

关 键 词：传感器 导模共振 亚波长光栅 严格耦合波分析 

分 类 号：TP212.14[自动化与计算机技术—检测技术与自动化装置]