Real Time And Wide Band Photonic Crystal Biosensor

With the improvement of medical and health issues, the requirements for fast, accurate and convenient detection technology are more urgent. Photonic crystal biosensors,which can reflect changes of biological molecular weight by nanoscale measurement and spectral analysis, have attracted a lot of attention. This paper presents a new model of biosensor, based on two-dimensional triangular lattice photonic crystal which is made of silicon. This model is able to monitor the change of the concentration of the analyte in real time easily, reusable and fast. The structure parameters of the model are optimized according to the reflection model through mathematical deduction and then the technological process for making this structure is designed in this paper. To verify the performance of the biosensor, an experiment for testing the glucose solution is designed and implemented. Then a searching algorithm along a wide spectrum is put forward and used in processing the spectral data, through which the substrate concentration can be measured accurately, automatically and in real time.Firstly, the master equation of the 2D photonic crystal is derived from the Maxwell equation group. On this basis, the band structures of the simple lattice 2D photonic crystal and photonic crystal waveguide are studied. And the photonic crystal reflection model of the photonic crystal is achieved with rigorous coupled wave method.Secondly, according to optimal theory model, the influence of the structure parameters such as the lattice period and duty cycle on the characteristics of the biosensor is studied. And considering the existing production process level of nano materials, the structure parameters of this biosensor are finally determined, and the final structure is simulated and analyzed. This structure template is fabricated by the designed process in this paper, and the morphological characteristics are identified by scanning electron microscopy. And at the same time, the optical properties of the system are verified by the spectral imaging system.Finally, a platform of two-dimensional photonic crystal biosensor spectral imaging testing system is established. Reflection spectrums of glucose at different concentrations are collected through the experiment which designed and implemented independently. The spectral data obtained during in experiment are analyzed, and compared with the theoretical model. The results are linear as well as theory. Combined with smoothing filter, Hilbert transform and Gauss fitting, an automatic fast searching algorithm is proposed. So a convenient and feasible scheme for the practical application of photonic crystal biosensor is explored as well.