Research On The Performances Of Silicon-Based Micro/Nano Optical Biosensors

Thanks to its various unique features including non-destructive detection,strong anti-electromagnetic interference ability,high sensivitity and fast read rate in comparision with tranditional electrochemical biosensors,the optical biosensors have wide-range applications in these fields,such as drug devolepments,medical diagnosis,environmental monitoring and food safety.Recently years,due to its established features including small footprint,low cost,high sensitivity and convenience of integration,silicon-based micro/nano-structure optical biosensors have attracted widely attention of researchers.This thesis novelty proposed several kinds of silicon-based micro/nano-structure optical biosensors and presented its design methods and sensitivity performances,laying a solid theoretical foundation for the realization of high-performance label free biosensing technology.The main work of this thesis includes several items as follows:Firstly,the concept and advantages of optical biosensors are introduced.The features of silicon-based micro/nano-structure optical biosensors are introduced,and the several kinds of commom structures including photonic crystals(PhC),whispering-gallery-modes(WGM)microcavities and interferometer structures are listed.The silicon-based optical cavities and its material characteristics are briefly introduced.In addition,the two common principles used to research on reasonant cavities including Transfer matrix method(TMM)and Finite-Time Domain-Difference method(FDTD)are described.Then a common structure in WGM microcavities,namely microring resonant cavities(MRRs)is introduced,and its two coupling structures are presented,respectively.Meanwhile,the concept of one-dimensional photonic crystals(1D-PhC)is introduced and the model of 1D-PhC is presented.The Coupled-Mode Theory(CMT)is employed to analyze its transmission characteristics and the sensitivity performances are analyzed.Secondly,the uniform PhC integrated to MRR based sensitivity structures is designed.In this structure,the Autler-Townes splitting is introduced,achieving the enhancement of sensitivity performances.In this part,the simulation software is used to design and optimize the uniform PhC,attaining the ideal transmission spectrum and device geometrical parameters.Then the sensitivity performances of proposed device are presented,and its advantages in sensitivity applications are analyzed.Thirdly,a 1D PhC integrated to MRR based sensitivity structures is designed.The concept of Fano resonances is introduced and the operation principle of this device is analyzed.In order to obtain ideal transmission spectrum,the device is decomposed to two indepent element,namely 1D PhC and MRR.The design for proposed device mainly focous on 1D PhC cavity.Then the device structure is optimized to obtain more ideal transmission characteristics.The sensitivity performances of proposed is presented when the optimized steps is achieved.Finally,a flexible building block cell called uniform photonic crystal microring resonant structure is investigated and demonstrated.In this part,the FDTD methods are employed to structure design and characteristic study.This structure generating several physical effects including slow light effect,Vernier effect and orbital angular momentum emitting is a block cell with high performance and multi-functionality,resulting in wide-range applications in the fields of integrated optics.