Laser-Scanning Surface Plasmon Polariton Resonance Microscopy with Multiple Photodetectors

We report the development of a laser-scanning surface plasmon resonance microscope equipped with multiple photodetectors. The system simultaneously obtains images that have different orientations to the specimen under examination, and the system can achieve a spatial resolution of 1.6 (mu)m, which is shorter than the propagation length of the scanning surface plasmons, while high sensitivity to thickness and refractive-index distributions is retained. In addition, because the system uses a laser-scanning microscope, it can obtain highcontrast images. The measurable ranges of refractive-index distributions and thicknesses of specimens that can be measured are also discussed.