Research On A Silicon-based Photonic Crystal Structure Sensor Device In The Near-infrared Band

Photonic crystal is a spatial periodic and artificial electromagnetic structure with photonic band gap characteristics.It has been widely used in many optical functional devices because of its powerful light control ability,and photonic crystal biosensor is one of them.Optical biosensors have become the hot research topic because of their advantages of energy saving,environmental protection,strong anti-interference ability and rapid response.The silicon material has excellent characteristics such as high refractive index and low loss in the near-infrared communication band.With the rapid development of CMOS technology and on-chip integration technology,near-infrared-band silicon-based photonic crystal functional devices have unique advantages in terms of performance and production cost.This paper proposes to study the near-infrared band silicon-based photonic crystal structure sensor parts,which has important physical significance and great practical application prospectsWe propose an ideal two-dimensional triangular lattice photonic crystal sensing unit.By changing the shape and size of the rods on the incident and exit faces of the triangular lattice photonic crystal,the surface local mode with strong spatial local characteristic is obtained.The rod is changed from a conventional circular shape to an elliptical shape,and the elliptical shapes of the adjacent two columns have short semi-axes of the same size and long semi-axes of different sizes.In the middle region of the photonic crystal structure,the central defect mode is formed by changing the size of the circular rods.We use biological or chemical bonding methods to allow different types of analytes to be adsorbed around defects in different positions of the photonic crystal.Therefore,by detecting the change of the wavelength position corresponding to the plurality of defect modes in the broad spectrum and the change of the transmittance thereof,the thickness of the plurality of types of analytes adsorbed around the defect body is obtained.Two-dimensional slab photonic crystals can regulate the transmission of light through the photonic bandgap,and rely on total reflection to control the transmission of light in the third direction.Compared to the ideal two-dimensional photonic crystal,theirs size is smaller and more convenient for practical applications.Through parameter optimization,we designed the near-infrared square-array two-dimensional slab photonic crystal sensing structures with good sensing characteristics,and the defects supporting the intermediate defect modes and the surface local modes are round.The upper and lower surfaces of the silicon column are all glass,and the liquid to be tested can flow in the gap between the rods between the two layers of glass,thereby facilitating dynamic and real-time monitoring of the liquid to be tested.By designing the asymmetric sensing structure,seven kinds of adsorption conditions of three kinds of analytes can be measured,which lays an important theoretical foundation for the smooth development of the next experimental work.