Partially Coherent Imaging and Interferometry Based on Diffraction Gratings.

Interest in using diffraction gratings as elements of an interferometer has recently been rejuvenated. Likewise, a phenomenon based on diffraction gratings, Lau imaging, has received much attention. The three major objectives of this thesis are to integrate grating interferometers into a general theory of gratings imaging gratings; extend the usefulness of grating interferometers; and to quantitatively express the difference between grating and classical interferometers. The theory of a grating interferometer is shown to be related to the theory of Lau imaging. The concept of one grating imaging another grating is stressed, rather than a simple interference process. Lau imaging is then extended even further into a general theory of one periodic structure imaging another periodic structure. A detailed theory is developed which expresses the image irradiance in terms of the object and "imaging" element. The two grating interferometer is then extended to multiple gratings. By extending the number of gratings, in particular to three, the usefulness of a grating interferometer is significantly increased. The advantage of using a grating interferometer over a classical interferometer is not readily apparent. A detailed comparison of a grating interferometer with its classical counterpart, the Mach-Zender interferometer is included in order to elucidate the major advantages of the grating interferometer. Finally, applications and experimental results are presented which show the unique advantages of using the extended grating interferometer for various optical processes.PhDOpticsUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/159465/1/8314366.pd