An optofluidics biosensor consisted of high-finesse Fabry-Pérot resonator and micro-fluidic channel

A high quality factor Fabry–Pérot cavity (FPC) biosensor with smooth and flat micro-channel surface is realized by using a silicon on insulator substrate, in which the oxide layer functions as an etch-stop layer. The measured quality factor and sensitivity of the FPC biosensor are 861 and 1100 nm/RIU (refractive index units), respectively, and the corresponding detection limit (DL) reaches 1.1 × 10−5 RIU. Moreover, due to the smooth and flat channel surface, higher quality factor and better DL can be obtained with increasing reflectivity of the Bragg reflector of the FPC biosensor.