反对称模平面光波导生物传感器的研究与设计

Study and Design of Reverse-symmetry Planar Optical Waveguides Biosensors

通过数值分析的方法,证明了反对称模式结构中由于消逝波的能量更多地集中于待测层,因此它具有更高的灵敏度。为使反对称模光波导生物传感器作为微折射率计使用的实时过程中灵敏度始终保持在0.2到0.9间,在设定衬底材料折射率的前提下,得出不同设计条件下各参数之间的约束关系1)设计前已确定了波导材料情况下,存在最大可测量覆盖层折射率;2)在需要的可测覆盖层折射率范围已确定情况下,存在最小的可用的波导层折射率;3)以上两种情况下,如工作用最大的可测覆盖层折射率及波导材料都确定了,则在波导层制造中必须使其厚度满足特定的要求。

Compared with normal-symmetry planar optical waveguide biosensors,the reverse-symmetry has deeper penetration,because the energy of evanescent wave distribution in substrate is much less than that in cover,where the analyte is located. Its sensitivity is also proved higher. So we present a new design to achieve high sensitivity （between 0. 2 and 0. 9） of dynamic monitoring for reverse-symmetry planar optical waveguides biosensors,according to different aim. One is that,when the material of the waveguides film is already chosen, we can get the possible maximum cover refractive index change; the other is that,when we make the sensor＇s maximum cover refractive index change suit definite requirement,we can get the minimum of the refractive index of waveguides film. And no matter which aim is,when the maximum cover refractive index change nad the index of waveguides are chosen,the thickness of the waveguide must limited in the definite range.