Integrated prism-free coupled surface plasmon resonance biochemical sensor

We present the design, implementation and characterization of an integrated surface plasmon resonance biosensor chip involving diffractive optical coupling elements avoiding the need of prism coupling. The integrated sensor chip uses the angular interrogation principle and includes two diffraction gratings and the SPR sensing zone. The theoretical design is presented as well as the fabrication procedure. Experimental results, using reference index fluids, are compared to theoretical predictions and prism coupling experimental results. We believe that this architecture is perfectly suitable for low cost and reproducible SPR biochemical sensor chips since the sensing zone can be functionalized as any other one.