Resolution is an imaging system's ability to distinguish object detail. The resolution ability is ultimately limited by diffraction, which is hard to avoid because it comes from the wave nature of light. The Rayleigh criterion given by the finite width of the Airy disk, is the generally accepted criterion for the minimum resolvable detail. This criterion was hard to overcome until the study of Optical Vortex Coronagraph (OVC) system. This system can eliminate the component of light that creates Airy disk. The left light, which can pass through the OVC system, contains spatial information from the observed object even if it is an unresolved object as defined by the Rayleigh criterion. This thesis challenges the Rayleigh criterion using the OVC system. It is not hard to obtain the feature information of a object by detecting the light power that enters the system and the power that eventually passes through the system. A binary points source example in this thesis shows that, even if the source is unresolved under the Rayleigh criterion, its power transmission contains the information of angular extent of the two points sources. The power transmission of an ellipse object can differentiate tiny differences between its long radius and short radius.
Library of Congress Subject Headings
Resolution (Optics); Optical measurements; Coronagraphs
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Han, Jiaxuan, "Imaging unresolved object using vortex mode detection" (2012). Thesis. Rochester Institute of Technology. Accessed from
RIT – Main Campus