Fabry-perot interferometric surface-stress sensor with high wavelength selectivity for label-free biosensing

We developed a MEMS Fabry-Perot interferometer with high wavelength selectivity by using Au half-mirrors for a highly sensitive label-free biosensor. The proposed optical interferometer can perform signal conversion from membrane deformation caused by biomolecule adsorption to electrical readout signal in an exponential manner by using the gradient of the transmitted interference spectrum. By integrating 50-nm-thick Au half-mirrors, wavelength selectivity improved to be 6.5 times. We successfully demonstrated spectral shift of 40 nm caused by membrane deflection due to BSA antigen-antibody reaction on the optical interferometric sensor.