Imaging interferometric microscopy.

We introduce and demonstrate a new microscopy concept: imaging interferometric microscopy (IIM), which is related to holography, synthetic-aperture imaging, and off-axis-dark-field illumination techniques. IIM is a wavelength-division multiplex approach to image formation that combines multiple images covering different spatial-frequency regions to form a composite image with a resolution much greater than that permitted by the same optical system using conventional techniques. This new type of microscopy involves both off-axis coherent illumination and reinjection of appropriate zero-order reference beams. Images demonstrate high resolution, comparable with that of a high-numerical-aperture (NA) objective, while they retain the long working distance, the large depth of field, and the large field of view of a low-NA objective. A Fourier-optics model of IIM is in good agreement with the experiment.