colloidal lithography: from surface modifications to biophotonics applications

‎: 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.‎