Partially coherent phase microscopy with arbitrary illumination source shape

We propose a method that recovers phase from a stack of through-focus intensity images taken with a partially coherent microscope employing illumination of any arbitrary source shape. Our algorithm uses a Kalman filtering approach, which is fast, accurate and robust to noise. We validate the method in simulation and with experimental data taken on a commercial microscope with varying condenser apertures in Köhler geometry. OCIS codes: 100.5070, 100.3010. Phase can be reconstructed from a series of through–focus intensity images taken by a microscope or 4f system (see Fig. 1) [1–4]. In previous methods, the illumination is assumed to be spatially coherent, although it may actually be partially coherent. The coherence of a brightfield microscope, for example, can be controlled by changing the condenser aperture shape; smaller apertures improve coherence at the cost of light throughput and resolution. We demonstrate here a phase imaging method that can handle arbitrary source (aperture) shapes, giving accurate phase results with any illumination coherence. Further, we show that not only can coherence be incorporated, but there may be some advantages in using non-traditional source shapes for phase imaging. These ideas are inspired by the lithography industry, where it is well known that the source shape can be optimized for example, dipole or multi-pole illumination is widely used for accentuating specific spatial frequencies. z stage Experi etal setup: Nikon TE300