Mid-infrared Biosensor Based on Bloch Surface Mode Excitation in Truncated One-Dimensional Ternary Photonic Crystal Under Kretschmann Configuration

We have theoretically investigated the performance of mid-infrared (mid-IR) sensitive biosensor constructed by truncated one-dimensional (1D) ternary photonic crystal (TPC) on the prism base under Kretschmann configuration coupling technique. The control over resonance wavelength (RW) of the excited Bloch surface modes (EBSMs) for the case of incident transverse magnetic polarized electromagnetic waves (EMWs) has been shown. The band structures and the reflection spectra of the considered model are computed using transfer matrix method (TMM). The variation in different design parameters of the theoretically constructed biosensor, such as thickness of the truncation layer, refractive index of the sensing medium, and number of unit cells in photonic crystal (PC), allows us to have good control over the resonance wavelengths in fixed frequency regime of the PBGs. The excitation of BSMs is characterized by a dip in the reflectance spectra. The measured sensitivity of the sensor is 10-3 orders of magnitude sensitive to the change in dc and dt values.