1D Photonic Crystal-Based Biosensor for Multiple Biomarkers Detection

In this paper, a highly sensitive 1D photonic crystal (1DPC) based biosensor is introduced and theoretically studied using the transfer matrix method, which has the capability of detecting multiple biomarkers, simultaneously. An m by n gradient refractive index (GRIN) lens array is introduced to the center of a 1DPC structure as a defect layer that is surrounded by two microfluidic channels. By irradiating a natural light source to the structure, a multiple array of the concentric rainbow appears on the output plane. The frequency range of these rainbows is highly dependent on the effective refractive index of the fluid inside the two microfluidic channels. By functionalizing the surfaces around the channels with an m by n antibody array along with the interaction of the various biomarkers, each element of the rainbow array displays the changes in the concentration of a different biomarker. Any change in the concentration of the biomarkers can cause a variation in the effective refractive index of the fluid and thus lead to a shift in the generated rainbow frequency range of the output. The size and number of the generated rainbow array may be engineered by using the central defect layer's refractive index distribution function.