Partially coherent image formation in Asymmetric illumination-based differential phase contrast (AIDPC) and phase-retrieval

Abstract

Differential phase contrast (DPC) was first proposed in scanning electron and optical microscopy to image gradient of the specimen's optical path length. We introduced AIDPC as an oblique illumination-based partially coherent imaging method which is a full-field equivalent of the scanning DPC system. We described imaging with AIDPC assuming a slowly varying specimen. Recently, we have developed an accurate paraxial phase-space model, termed phase-space imager (PSI), for describing image formation in a general partially coherent system. In this paper, we use PSI to compute partially coherent images of a general 2D specimen. We also simulate phase-retrieval process with AIDPC. These accurate simulated results, presented for the fist time, provide evaluation of the key steps involved in phase-retrieval using AIDPC. © 2010 American Institute of Physics.