Passive synthetic aperture imaging using an achromatic grating interferometer

Synthetic aperture imaging with active systems is relatively well developed. The implementation of passive systems, on the other hand, is being hindered by a low SNR and the difficulty in achieving 2-D aperture fill. The achromaticity of the grating interferometer permits the use of a wider instantaneous spectral bandwidth to produce better SNR, and it provides a simple means to synthesize a 2-D aperture. A passive synthetic aperture imaging approach implemented with an achromatic grating interferometer is described, and laboratory experimental results are presented to demonstrate the proposed concept.