Proposal of a new optical system for prism-based surface-plasmon-resonance imaging

We propose a new prism-based surface-plasmon-resonance microscope (PB-SPRM) with a diffraction grating. Unlike the conventional PB-SPRM, the proposed one is free from distortion and blur, which were introduced because of the inclination of an object plane against one normal to the optical axis. To solve this problem, we inserted a reflection-type diffraction grating into the conventional PB-SPRM between the sample and the objective lens. Also, we placed an aperture on the back focal plane of the objective lens so that an object-side telecentric (OST) optical system was formed. By this optical configuration, a wide field of view (FOV) and a high frame rate were also obtained. We describe the theoretical background for designing the new PB-SPRM. In order to evaluate the performance of the proposed system, we show some numerical simulation results in detail. Mixing water and an ethanol–water solution along a micro-flow channel at a rate of 30 frames/s is also shown.