带多孔硅表面缺陷腔的半无限光子晶体Tamm态及其折射率传感机理

Tamm state of semi-infinite photonic crystal based on surface defect cavity with porous silicon and its refractive index sensing mechanism

结合表面缺陷半无限光子晶体Tamm态与多孔硅光学传感机理,在光子晶体表面缺陷腔中引入多孔硅,并利用其高效的承载机制,提出基于多孔硅表面缺陷光子晶体Tamm态的折射率传感结构.在半无限光子晶体中缺陷腔与原来的周期性分层介质结构的界面上存在Tamm态,通过入射角度调制使其在缺陷腔中实现多次全反射,并在缺陷腔中加入吸收介质,使谐振波长在缺陷腔中完成衰荡,从而在反射谱中得到缺陷峰;调整光子晶体参数,使缺陷峰的半高全宽得到优化,提高其品质因数(Q值);在此基础上,根据Goos-H?nchen相位移与谐振波长的关系,建立由待测样本折射率改变所导致的多孔硅表面吸附层有效折射率变化与缺陷峰值波长漂移之间的关系模型,并分析其折射率传感特性.结果表明,此生物传感结构Q值为1429,灵敏度为546.67 nm/RIU,证明了该传感结构的有效性,可为高Q值和高灵敏度折射率传感器的设计提供一定的理论参考.

A refractive index sensing structure based on the Tamm state of photonic crystal with surface defect is proposed by combing the Tamm state of semi-infinite photonic crystal with the optical sensing mechanism of porous silicon, in which the e？cient bearing mechanism of the porous silicon is introduced into the surface defect cavity. The existence of Tamm state is demonstrated at the edge between the defect cavity and the periodical photonic crystal structure, and the total reflection in the defect cavity is formed by adjusting the incident angle. The resonant defect peak is obtained in the reflection spectrum by adding an absorbing medium into the defect cavity in order to reduce the reflectivity of the resonant wavelength. The full width at half maximum and the quality factor （Q value） can be optimized by adjusting the parameters of photonic crystal. Based on those results, according to the relationship between Goos-Hanchen phase shift and the resonant wavelength, the model for the relationship between the resonant wavelength and the effective refractive index variation of porous silicon adsorbing layer caused by the change of the refractive index of the sample is established, and its refractive index sensing characteristics are analyzed. The numerical simulation results show that the Q value can attain to 1429 and the sensitivity is about 546.67 nm·RIU^-1, which can demonstrate the effectiveness of the structure design and provide some theoretical references for designing the refractive index sensors with high Q values and sensitivities.