Study On Photonic Crystals Biosenor Based On Rigorous Coupled-wave Analysis

Since the conception of photonic crystal was proposed in1987, the study and applicationof photonic crystal has been widely developed. In2004, University of Pittsburgh in UnitedStates applied photonic crystal sensor into biosensing techniques and proposed the conceptionof photonic crystal biosensor systematically, this also marks the birth of photonic crystalbiosensor.In this paper we researched the influence of the senor structure to the sensitivity. Aphotonic crystal biosensor with a period of1000nm is proposed on a substrate. Then a highrefractive index material is deposited on the surface of the photonic crystal. We determine therelationship between the peak reflection wavelength and the effective refractive index.The rigorous coupled-wave theory is employed to analyze the characteristics of thenarrow-band infrared reflection spectrum of the photonic crystal biosensor. With concentrationof the analyte adsorbed on the surface of the photonic crystal varying, the effective refractiveindex changes simultaneously. The shift of the peak wavelength of reflection is linear to thechange of the analyte index.The influence of the coating with different refractive indices, thicknesses, filling ratios,waveguide refractive indices and its thickness and substrate refractive indices on the reflectionspectrum and sensitivity of the shift of the peak reflection wavelength is also studied. Theresults indicate that the sensitivity of the biosensor can be improved by selecting appropriateparameters of the parameters.In addition, temperature is considered to the influence of the sensor. In some condition,we can ignore the effect of the temperature.In summary, this paper provided a certain value for the optimization for photonic crystalbiosensor design.