A New-type Thermal Light Correlated Imaging

Correlated imaging as a new imaging technique,since the nineties of last century has been widely studied.Correlated imaging is different from the ordinary imaging,whose imaging features break people's understanding of optical imaging.Because an object and an image seems to not be in the same optical path and even a lensless correlated imaging can also be performed.The first implementation of the correlated imaging is carried out by the entangled light source,and the recent studies found that thermal light can also be used to achieve correlated imaging.With the continuous development of correlated imaging,people's requirements for image quality are getting higher and higher,Visibility is one of the important parameters of evaluating image quality,which has been valued by scientific researchers in correlated imaging field.Based on the traditional correlation imaging method,a new type of thermal correlation imaging scheme is proposed in the detection arm and the reference arm by using spatial resolving CCD camera.In this paper,we first use the method of combinations in mathematics,to compare the relationship between the order of the intensity of the detection arm and the order of the reference arm.The high-order imaging theory is developed in the form of the first order correlation imaging function and then we have a more clear understanding of the high-order correlated imaging in theory.Secondly,since the detectors we use are two spatial resolving CCD cameras,an experimental scheme to improve the visibility of correlated imaging is proposed.We first carry out the high-order self-correlation of the spatial distribution of the intensity detected by the test detector and then sum them by pixels as a bucket signal,which is used to correlated with the reference arm light intensity according to the second-order intensity correlation function of thermal correlated imaging;Finally,according to the previous theory,the correlated imaging experiment on the first-to fifth-order self-correlation of the intensity in the detection arm is respectively carried out.After comparing the post-processing of the experimentaldata and the results of the correlation imaging,it is found that the visibility of the correlation imaging increases with the increase of the order.