An ultra-low detection-limit optofluidic biosensor with integrated dual-channel Fabry-Perot cavity

A silicon-on-insulator based optofluidic biosensor with integrated dual-channel Fabry-Perot cavity is proposed for optical differential detection. A detection limit of 5.5 x 10(-8) refractive index unit is experimentally demonstrated, owing to the high quality factor of the cavity and the differential detection, which can extract the small signal for efficient amplification and greatly reduce the system noise. Moreover, the measurement system features low cost compared with that of surface-plasmon-resonance sensor and ring-resonator sensor. (C) 2013 AIP Publishing LLC [http://dx.doi.org/10.1063/1.4802805]