Study On Second-order Correlated Imaging With Pseudo-thermal Light

Correlated imaging is a new type of imaging system which is also named ghost imaging or quantum imaging in the history.It has widely attracted attentions of scientists and engineers recent years because of its novel properties and potential applications in remote sensing,biomedical imaging and so on.Classical imaging system is based on the point-to-point correspondence between the object plane and the imaging plane.Correlated imaging retrieves an unknown object by measuring the second-order correlation function between the test light field and the reference light field.The test light field interacting with the object is collected by a bucket detector without spatial resolution,while the reference light field is detected by a spatial resolving detector without interacting with the object.In fact,neither the test nor the reference field can reconstruct the image of the object.Correlated imaging,which is the combination of signal correlation technology and quantum optics,has the following advantages:(1)the object and scanning detector are separated,yielding nonlocal imaging reconstruction;(2)can achieve single pixel imaging;(3)can achieve lensless imaging;(4)is robust against disturbance,such as atmospheric turbulences and scattering media.However,correlated imaging also meet some challenges: the first is low signal-noise-ratio of correlated imaging based on thermal light especially for the gray object,preventing the obtainment of highly qualified imaging;the second is the time-consuming storage and calculation process yielding it unable to realize online imaging.Since these two disadvantages limit the practical applications of correlated imaging,solving these problems is not only the focus of the current research,but also the main work of this thesis.In this dissertation,we firstly demonstrated the robust property of lensless correlated imaging system for the half-optical path.Secondly,we analyzed the influence of aberrations for the imaging quality of correlated imaging system and further studied the relationship between the position of the lens and the image quality.In addition,unifying the arithmetic of Differential Ghost Imaging(DGI)and classical GI,we proposed the Arbitrary Differential Ghost Imaging(ADGI)and developed Iterated Differential Ghost Imaging(IDGI),which could improve imaging qualify using the same data.Finally,the Sequence Differential ghost imaging(SDGI),which is a new algorithm,is proposed to save volume of data and time of computation.What is more,we explored the hardware system to achieve the online correlated imaging,which is an important step towards real-time imaging.In a word,our work is benefit to both the fundamental properties and the practical applications of correlated imaging.