Excitation-detection integrated trapezoidal prism-coupled surface plasmon resonance based on a compact optical system

A trapezoidal prism-coupled surface plasmon resonance (SPR) with excitation-detection integration is proposed and it is demonstrated that the integration of SPR excitation and detection can enhance the stability and portability of the system. In this SPR system, a new trapezoidal prism is used as a coupling element, and the advancement brought by replacing the traditional triangular prism with a trapezoidal prism can be summarized as followings: (1) The optical system is more concise and more conducive to the miniaturization, (2) Due to the precise and self-calibrated excitation angle brought by trapezoidal prism, the necessary fine adjustment steps for system assembly and adjustment can be avoided. Additionally, the excitation-detection integration is achieved by this integrated SPR, and the spectral detection is realized by employing a spatial intensity-based spectral information extraction. The experimental results show that this excitation-detection integrated SPR system has high sensitivity (20253 pixels/RIU), good stability (less than 4 pixels), repeatability (less than 2 pixels) and good portability. Additionally, the results of IgG binding show that this proposed SPR system has the potential for biochemical detection.