We report on the first polarimetric plasmonic biosensor based on arrays of bowtie nanoantennas. Using the Finite
Element Method (FEM) the phase retardation between the components of light polarized parallel and perpendicular to
the axis of the nanoantennas is studied. After optimizing them for high volumetric sensitivity at a wavelength of 780 nm,
sensitivities ~5 rad/RIU are obtained, corresponding to a detection limit ~10<sup>-7</sup> RIU when using the polarimetric readout platform. Surface sensitivity values resulted from studies of phase retardation changes from a coverage of bioreceptors
We report the first demonstration of real-time biosensing in free standing macroporous alumina membranes. The membranes with their 200 nm diameter pores are ideal candidates for biosensing applications where fast response times for small sample volumes are needed as they allow analytes to flow through the pores close to the bioreceptors immobilized on the pores walls. A bulk refractive index sensitivity of 5.2x10<sup>-6</sup> refractive index units was obtained from signal responses to different concentrations of NaCl solutions flowing through the pores. Finally, after functionalizing the alumina pore surfaces with an epoxysilane and then spotting it with β-Lactoglobulin protein, the interactions between the β-lactoglobulin and rabbit anti-β-lactoglobulin, as well as the interaction between the rabbit anti-β-lactoglobulin and a secondary antibody anti-rabbit Immunoglobulin G were monitored in real-time.
The modeling, fabrication and characterization of PSi fabricated from both (110) and (100) surface oriented silicon for
optical sensing is thoroughly reported. First, based on the generalized Bruggeman method, the birefringence and
sensitivity of the fabricated membranes were calculated as a function of the fabrication parameters such as porosity and
pore sizes; and external effects, such as the pores surface oxidation. Thereafter we report on the fabrication of PSi
membranes from (110) and (100) surface oriented silicon with pore sizes in the range of 50 - 80 nm, and the
characterization of their birefringence using a polarimetric setup. Their sensitivities were determined by filling the pores
with several liquids having different refractive index. As a result, sensitivities as high as 1407 nm/RIU were obtained for
the (110) samples at a 1500 nm wavelength and 382 nm/RIU for the (100) samples at the same wavelength.