New type small-angle sensor based on the surface plasmon resonance technology

In this paper, a new type small-angle sensor based on the surface plasmon resonance (SPR) technology is proposed. Two right angle prisms are mounted on two high precision rotation stages, respectively. When the light source passes through this experimental structure, we can achieve the small rotation angle only by measuring the output powers by uses of two photo-detectors. The resolution of the system can reach 1.2×10^-6 radian.