Comparison of surface plasmon resonance devices for acoustic wave detection in liquid.

Surface plasmon resonance (SPR) sensors represent a suitable method for broadband acoustic pulse detection. The reflectivity and phase of a p-polarized laser beam incident on an optical device under SPR conditions are strongly dependent on ambient conditions that are changed by an acoustic wave. Depending on the order of layers, SPR sensors can be arranged in the Kretschmann or in the Otto configuration acting as a pressure or as a displacement sensor. The aim of this study was to compare both configurations and to find linear and sensitive conditions for the application. Numerical calculations were carried out varying the layer dimensions and the angle of incidence. The results of the experimental investigation on both configurations confirm the working principle.