Abstract：Surface Plasmon microscopy can measure local changes of refractive index on the micron scale and has been successfully applied in biomedical or semiconductor material fields. Here, we propose and develop a novel confocal-setup based interferometric SPs microscopy. This technique delivers quantitative high spatial resolution sensitive to refractive index and offers the advantages of simpler and more stable alternative compared to the conventional two-arm based heterodyne interferometer. Furthermore, this technique allows the image contract to be controlled by varying the sample defocus without substantially degrading spatial resolution. We also verify the technique theoretically and experimentally.
