Third-order Double-slit Interference With Pseudo-thermal Light

In 1995,the first "ghost" interference(GI)experiment was performed with the quantum entanglement source produced through spontaneous parametric down conversion by Shih's group in the university of Maryland.After following more than 20 years,this kind of novel optical phenomenon has caused wide attention in the field of quantum physics and much theoretical and experimental research has been carried out.It is found that not only the entangled light source can be used in the ghost interference,but also the thermal source can be.However,second order ghost interference with thermal source has a low visibility that can never exceed 1/3,and is much less than that of GI with entangled light.Recently,studies on the higher-order intensity correlation effects of thermal light show that the visibility can be significantly improved by increasing the order N.which can overcome the disadvantages of the low visibility.Therefore,the high-order correlation properties of thermal light become one of research hotspots in the field of quantum imaging.In this paper,according to the theoretical analysis in Ref[71],we have performed a third-order double-silt interference experiment with pseudo-thermal light source by actually recording the intensities in two optical paths.In the experiment,through changing the size of light source,the visibility and resolution of the interference pattern and the effects of other parameters on them are systematically studied.By comparing the second-order and third-order double-slit interference pattern,it is found that the visibility of the third order interference pattern is much higher than that of the second-order GI.It can be also seen that under the same experimental conditions,the resolution of the third-order double-slit interference is the same with the second order,which is determined by the correlation length at the detection plane and increases with the increase of the diameter of the light source.It is shown that the visibility of the interference pattern is related to k,which is the ratio of the transverse size of the double slit and the transverse size of the light source,and that of both the second and third order interference increases with the increase of k.