Polarization-dependent sensing of a self-assembled monolayer using biaxial nanohole arrays

We demonstrate surface plasmon resonance (SPR) sensing based on the polarization-dependent extraordinary optical transmission through a biaxial nanohole array. The biaxial array has two periodicities in a single array that can be individually probed by varying polarization. Here, the SPR polarization-spectral dependence is demonstrated for the detection of a self-assembled monolayer for four sets of biaxial array periodicities. By monitoring the polarization dependence of transmission through the nanohole arrays with biaxial periodicity, surface-sensitive refractive index induced intensity variations may be separated from other effects such as absorption, scattering, and intensity fluctuations, while using a single wavelength source. Biaxial sensing is useful for ongoing microfluidic integration of nanohole SPR, where the light source is transmitted through a microfluidic channel. (C) 2008 American Institute of Physics.