The research described in this proposal is concerned with modelling and correcting the deleterious effects of instrumental polarization in imaging systems. It is motivated by applications in biomedical microscopy, and uses microscopy as a theoretical and experimental model system, but the problems, methods, and results of this research are of broad significance in optical engineering. Models for image formation, degradation and restoration will be based on the polarization aberration expansion, decomposing polarization variations in the pupil in a manner analogous to classical wave aberration theory. Models for two and three-dimensional imaging in tow specific systems, the polarization and differential interference contrast microscopes, will be developed and tested by experimental observations. Image quality will be evaluated by point-spread and modulation transfer functions. Methods for measuring polarization aberrations will be sought. Understanding image formation, degradation, and restoration in polarization-sensitive systems will provide guidance for future instrument designs, and will support a unified approach to system design through understanding the respective contributions and tradeoffs of the optics, image sensor, and post- processor.
