We describe, using a high-numerical-aperture vectorial model, the image formation of phase-contrast microscopes. In particular, imaging of a weak phase object is considered. We show that, partly owing to the fact that phase-contrast microscopes are interference microscopes, their image formation is fundamentally different from that of conventional transmission optical microscopes. Our detailed analysis reveals a number of yet undocumented properties of these microscopes, including that depending on the given configuration, they can exhibit an improved lateral resolution when larger detectors are used in comparison with that obtained for a small detector size. We present numerical examples to explain this phenomenon and discuss our analysis in detail.
© 2004 Optical Society of America
(120.5060) Instrumentation, measurement, and metrology : Phase modulation
(180.1790) Microscopy : Confocal microscopy
(180.5810) Microscopy : Scanning microscopy
(260.3160) Physical optics : Interference
Peter R. T. Munro and Peter Török, "Vectorial, high-numerical-aperture study of phase-contrast microscopes," J. Opt. Soc. Am. A 21, 1714-1723 (2004)