Doubling the field of view in off-axis low-coherence interferometric imaging

We present a new interferometric and holographic approach, named interferometry with doubled imaging area (IDIA), with which it is possible to double the camera field of view while performing off-axis interferometric imaging, without changing the imaging parameters, such as the magnification and the resolution. This technique enables quantitative amplitude and phase imaging of wider samples without reducing the acquisition frame rate due to scanning. The method is implemented using a compact interferometric module that connects to a regular digital camera, and is useful in a wide range of applications in which neither the field of view nor the acquisition rate can be compromised. Specifically, the IDIA principle allows doubling the off-axis interferometric field of view, which might be narrower than the camera field of view due to low-coherence illumination. We demonstrate the proposed technique for scan-free quantitative optical thickness imaging of microscopic biological samples, including live neurons and a human sperm cell in rapid motion under high magnification. In addition, we used the IDIA principle to perform non-destructive profilometry during a rapid lithography process of transparent structures. Light: Science & Applications (2014) 3, e151; doi:10.1038/lsa.2014.32; published online 14 March 2014