Research On Photonic Crystal Biosensor With High Sensing Performance Based On Defect Mode Coupling

Photonic crystals are periodic dielectric structures with photonic bandgaps and strong light-controlling properties.Optical biosensors have become a hotspot in biosensing fields because of their advantages of energy conservation,environmental protection,strong anti-interference ability and quick response.Silicon is widely used in infrared optical devices because of its high refractive index and low loss in the near infrared frequency range.Silicon-based photonic crystal biosensors have the advantages of high sensitivity,high resolution,strong anti-interference ability,small size,high integration,low energy consumption,environmental protection,and so on.Silicon-based photonic crystal biosensor becomes one of the future important trends.Because of the rapid development of CMOS technology and on-chip integration technology,silicon-based photonic crystal biosensors have great advantages in the industrial costs and industrial scale of production and have a significant value and a broad market potential.In this paper,one-dimensional silicon-based photonic crystals are studied.The finite-difference time-domain method is used to research the effect of different types of defect modes on the photonic crystal biosensors sensing performance.The influence of different defect types on the sensitivity of one-dimensional photonic crystal biosensor is analyzed by using the field energy distribution of the defective mode and the wavelength of the corresponding transmission peak in the transmission spectrum with the sensitivity of the refractive index change of the sample solution.Based on obtained conclusions,Under the condition of keeping the type of defective body unchanged,by using the method of changing the number of defective bodies and the coupling strength between the defective bodies,the mode field distribution and transmission spectrum of the resonant mode are analyzed and analyzed.Using the method of changing the number of defective bodies and the coupling strength between the defective bodies,this paper analyzes the mode distribution and transmission spectrum of the resonance mode,and explores the single-defect structure and multi-defect structure with different coupling strengths for the photonic crystal biosensor.Finally,a novel three-channel high-sensitivity real-time detection photonic crystal biosensor based on the coupling mode effect is innovatively proposed in this paper,and the mode field distribution and transmission spectrum of its working mode are analyzed with the change of the sample solution concentration.Finally,in order to verify the reliability of the designed multi-channel photonic crystal sensor,the situation that the sample to be tested is detected in different channels is designed,and the simulation results are obtained and further analyzed.In this paper,through simulated simulation,when the operating wavelength is adjusted to around 1550 nm,the refractive index sensitivity S is 820 nm/RIU,and the quality factor Q value reaches 2.5 ×105 which lays a firm foundation for the experimental preparation and practical application of high-sensitivity one-dimensional photonic crystal biosensors.