Phase manipulating Fresnel lenses for wide-field quantitative phase imaging

For well-magnified imaging systems that satisfy the Nyquist criterion, camera pixels resolve the fine details provided by the objective lens. However, the mismatch in a space-bandwidth product (SBP) between the objective lenses and digital cameras leads to major sacrifices in the optical field of view (FOV). This Letter presents a framework of phase manipulating Fresnel lenses (PMFL) to bridge this SBP gap in quantitative phase imaging (QPI) modality. This framework breaks through the conventional design paradigm of interferometric QPI, converting it from the combination of individual optical elements to a direct phase transform of the optical field. The wide-field QPI is implemented by a single dynamic PMFL mask, which conducts differential interference and scans the optical FOV across the camera sensor. We built a microscopic platform equipped with the PMFL module to image both natural and artificial samples and expanded the FOV for a given camera by factors of 3 × 3, 2 × 2, and 4 × 1, respectively.