Experimental approach to the microscopic phase-sensitive surface plasmon resonance biosensor

We designed and proposed a microscopic configuration of wide-dynamic-range phase-sensitive surface plasmon resonance biosensor based on differential interferometry between focused radially polarized and azimuthally polarized cylindrical vector beams recently (R. Wang et al., Opt. Lett. 37, 2091 (2012)). In this Letter, we follow the simulation results up with experimental verifications with a sensitivity of 7.385 x 10(-7) refractive index unit (RIU)/0.1 degrees. It is also verified that the dynamic range of this system could be as large as 0.35 RIU in principle, which is only confined by numerical aperture of the microscopic objective lens. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4773997]