Study On Sensing Characteristics Of Surface Defect Photonic Crystal

Based on the design and production of photonic crystal structure, the opticalbiosensor with characteristics of high detection sensitivity, high signal response speedand strong ability to resist electromagnetic interference, has become a hot issue inresearch of optical biosensor. Photonic crystal sensor with defect mode photoniccrystals structure using the different refractive index on sample solution analysisreflecting different spectral information, so as to realize the detection of concentration,composition, biomolecular interaction, dynamic change and other information.Introducing a defect in the surface of periodic structure of photonic crystal could formsurface wave, and electromagnetic field can make the role fully with sample solutionmolecules so as to improve the sensitivity of detection. Therefore, based on the studyof surface wave theory and optical properties of photonic crystal, a new refractiveindex sensor structure model based on photonic crystal with surface defect mode hasbeen proposed, and its sensing characteristics are analyzed. The main research worksare as follows:Firstly, we intensively study the formation mechanism of photonic crystal surfacewave, combine the surface wave resonance principle with photonic crystal opticalproperties, and construct the photonic crystal sensor structure model. We put absorbingmedium in the defect layer, and make the light occurring total reflection in the defectlayer surface. The mathematical model of the resonance peak and the refractive indexof solutions has been deduced by studying the resonance produced in defect layer andthe Goos-H nchen shift produced in total reflection.Secondly, the surface defect mode photonic crystal sensor structure has beencalculated numerically by the layered transfer matrix method, and its sensingcharacteristics has been analyzed. In order to improve the sensitivity and Q value ofthe sensor, the sensor structure parameters has been optimized. And the effectivenessof the refractive index sensor based on surface defect mode photonic crystal sensorstructure is verified by numerical simulation.Finally, based on realizing single point measurement in the surface defect mode photonic crystal sensor structure, the multi-channel detecting system device has beendesigned. Combined with the characteristics of SPR demodulation technology ofinformation, the sensor can realize the angle measurement of the sample, and use theMPP technology and CCD plane array imaging mechanism to test multiple samples atone scan cycle. Thus the sensor could realize the high throughput detection.