Adaptive optical design in surface plasma resonance sensor

A double-prism adaptive optical design in surface plasma resonance (SPR) sensor is proposed, which consists of two identical isosceles right-triangular prisms. One prism is used as a component of Kretschmann configuration, and the other is for regulation of the optical path. When double-prism structure is angle-scanned by an immovable incident ray, the output ray will be always parallel with the incident ray and just has a small displacement with the shift of output point. The output ray can be focused on a fixed photodetector by a convex lens. Thus it can be avoided that a prism and a photodetector rotate by θ and 2θ respectively in conventional angular scanning SPR sensor. This new design reduces the number of the movable components, makes the structure simple and compact, and makes the manipulation convenient.