Wide-field high-resolution surface-plasmon interference microscopy.

We describe a wide-field interferometric surface-plasmon microscope capable of submicrometer resolution. The system is a speckle-illuminated Linnik interferometer, which behaves as a wide-field analog of a scanning heterodyne interferometer. The presented images demonstrate contrast reversals at different defocus while retaining submicrometer lateral resolution. The contrast mechanisms are discussed as well as the instrumental requirements of the technique.