| Recently, with the development of optical sensing technology, label-free optical biosensor is becoming mainstream of optical sensing research, because of its special advantages of dispensation from fluorescent labeling, high sensitivity, compact structure and low cost in integration. This article aims to achieve high-performance optical label-free biosensor, we have designed a microdisk-shaped optical biosensor which is based on whispering gallery mode, and carried out research and analysis of its biological sensing properties. This paper mainly includes the following several aspects:Firstly, we design a microdisk resonator sensor which is based on whispering gallery mode by using FDTD method. On this basis, we propose two symmetric and asymmetric defect microdisk resonator structure, by FDTD simulation, the influence of microdisk rough edges Loss on resonant modes is analyzed. Then, we also studied the relationship between the curvature of the waveguide and coupling coefficient. In this thesis, two novel structures of embedded microdisk resonator are presented, the model is used to select the operating wavelength.Secondly, the biosensing properties of whispering microdisk are analyzed from the perspective of surface adsorption and bulk refractive index. We have studied the two forms of sensing: the refractive index sensing of bulk and surface adsorption. By FDTD simulation, the optimal sensing wavelength has been determined, and the sensitivity and detection limits of microdisk sensor are calculated. In the analysis of the surface adsorption simulation, the reaction process of molecular adsorption and quenching on the surface is achieved.Finally, a differential double microdisk sensor has been designed in order to achieve the purpose of eliminate common-mode interference signal. By FDTD method,the differential correction value to eliminate interference is obtained, and the sensitivity of microdisk sensor is differentially corrected. Next, we also simulate the molecular surface adsorption of differential double microdisk, the sensing response of molecules adsorption on surface of double microdisk are differentially corrected.In addition, in order to explore the integration of micro-fluidic channel and micro-disk sensor, a X-shaped microchannel structure is designed to pass the test solution. The theory of convection of the liquid under test is analyzed, the test fluid flowand molecular diffusion process of concentration in the channel are simulated which obtain the optimal design parameters of integrated fluidic channel. Finally, a integration array of microdisk sensors and X-shaped fluid channel is proposed. |
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