Theoretical Studies Of Second And Third-order Correlated Imaging

In recent years, much attention has been paid to correlated imaging whichis also called as ghost imaging or coincidence imaging: Usual correlated imaging is a technique which allows one to perform coherent imaging with incoherent light by exploiting the spatial correlation. Each of the correlated beams issent through a distinct imaging system, traditionally called the test and thereference arm. In the test arm an object is placed and information about theobject is recreated from the spatial correlation function between the test andreference arm in a nonlocal fashion by means of the second-order correlationmeasurement. Initially the possibility of performing correlated imaging wasascribed to the presence of spatial entanglement between the two arms. Itwas claimed that entanglement was a crucial prerequisite for achieving ghostimaging. Lately this view has been challenged from both theoretical and experimental aspects. It has been shown that classical correlation can play thesame or similar role as quantum entanglement. A thermal or quasi-thermalsource can exhibit such a classical correlation. Actually a very close formalanalogy was demonstrated between ghost imaging with thermal and quantumentangled beams, which implied that classically correlated beams were able toemulate all the relevant features of quantum ghost imaging, with the only exception of the visibility. Studies on ghost imaging has led to the developmentof a new field, named ghost imaging geometric optics.In previous correlated imaging schemes using thermal sources with classical correlation, only the second order correlation of the light field is used. Sothey may be called as the second-order correlated imaging which can give onlyone ghost image of an object. An interesting problem which rises naturally is how to create many ghost images from one object by correlated imagingsystems. As the simplest higher-order correlated imaging, in this paper, wepropose a third-order correlated imaging protocol to create two ghost imagesat two different places from one object through using a third-order correlatedthermal source and the third-order correlation measurement. The main resultsof the thesis include the following contents.(â…°) We propose a protocol to create two ghost images at two differentplaces from one object. This protocol involves two optical configurations: thedifferent-path ghost imaging configuration and the same-path ghost imagingconfiguration.(â…±) We calculate third-order correlation functions for the two ghost imaging configurations, and derive the corresponding Gaussian thin lens equationsin terms of the third-order correlation functions.(â…²) We develop the geometrical optics of the third-order correlated imaging processes for the two ghost imaging configurations. We investigate thegeometrical optics of the two ghost imaging configurations in detail throughanalyzing the third-order correlation functions and related correlated imagingequations and plotted the graphics of the geometrical optics. We discuss thevirtual or real characteristics of ghost images. It is indicated that the thirdorder correlated ghost imaging with thermal light exhibits richer correlatedimaging effects than the second-order correlated ghost imaging with thermallight.