Abstracts Category : Other

Gradient-index fiber array for imaging

by Xi (1973 Chen

In this thesis Fourier optics is used to analyze agradient-index (GRIN) rod and a GRIN fiber array With thisviewpoint we present several novel interpretations of the imagingof these systems, including derivations for the impulse responsesfor both Fourier transform planes and imaging planes, includingaberrations. In addition, both coherent and incoherentilluminations are considered. An effective aberration transmissionfunction is defined and calculated to have the diffraction effectand aberrations included in the Fourier optics. The theoreticalpredictions from the Fourier optics including aberrations are inexcellent agreement with the experimental results. This treatmentprovides a powerful tool for resolution and image quality analysisof a GRIN rod and a GRIN array. </br>Thedepth-of-field phenomenon for a GRIN array is quite different fromthat for a lens. We present both a geometrical optics based and aphysical optics analysis for the depth-of-field of the array. Toextend the depth-of-field, a novel design of phase masks with postdigital processing is proposed. Two fabrication techniques of masksare studied and compared. The experimental setup for measurement ofphase masks is established. The alignment of masks is studied. Thepoint-spread functions of the GRIN fiber array with phase masks fordefocused objects are calculated and digitally processed with themaximum entropy algorithm. The depth-of-field is expected to be 2to 3 times that for the uncorrected array.