Abstract
Surface plasmon for biosensing applications has high sensitivity. There are many types of surface plasmon biosensors today. We focus on the grating-based surface plasmon biosensors. The grating-based SP biosensor detects the biomolecule through interrogating the shift of reflection spectrum. By the simulation method of Finite Difference Time Domain (FTDT), we found that the bandwidth is generally related to the profile of the grating. A new grating-based surface plasmon biosensor is proposed. This surface plasmon grating featured by quadratic V-grooves showed a narrower spectral bandwidth, compared with conventional rectangular gratings with the same aspect ratio of the open trench. The experimental result confirmed improved sensor resolution. The sensitivity was measured to be 820 (nm/RIU) with various concentrations of salt solution. Real-time detection of avidin bound on biotin was presented.