A novel optical refractive index sensor based on VCSELs and gold nanoparticle arrays

In this paper, A high sensitivity sensor chip based on VCSELs and localized surface plasmon resonance of gold nanoparticle array is demonstrated. The anodic aluminum oxide film is used as a mask to fabricate the hexagonal arrays of Au nanoparticles by magnetron sputtering and lift-off process on the VCSELs’ end surface. Different concentrations of sucrose solution with the refractive index between 1.333 and 1.3998 are detected by the LSPR sensor which is constituted by VCSELs (light source), gold nanoparticle arrays (sensing layer) and microfluidic. The light intensity is varied by the change of the background refractive index. The experimental result shows that the optical output power of the biosensor depends on the refractive index in a nearly linear way. The maximum sensitivity is 1.1×105nW/RIU which is higher than that of biosensor based on the shift for resonance wavelength.