1D porous silicon photonic crystals comprising Tamm/Fano resonance as high performing optical sensors

We theoretically discuss a new design for the sensing and detection of chemical and biomedical fluids based on the change in their indices of refraction in the refractive index range 1−1.5. The transfer matrix method in cylindrical coordinates and the Bruggeman's effective medium approximation represent the theoretical overview of our study. The metallic cap in front of a ternary porous silicon photonic crystal induces Tamm / Fano states inside the photonic band gap that take part of the resonant peaks in conventional defected PCs. Analysis shows that the spectral positions of these states are very sensitive to changes in refractive index of the void fluids. In particular, the proposed sensor could provide higher performance than many previous 1D photonic crystals sensors. At a void refractive index of 1.1, our design exhibits a sensitivity of 6770 nm/RIU and a quality factor of 662. Therefore, the detection and sensing procedures of chemical and biomedical fluids could be investigated in a rather much efficient, stable and novel technique that has not been applied before.