Super-resolution Imaging By Anti-correlation Of Optical Intensities

Correlation imaging,also known as ghost imaging(GI),is an emerging imaging method,which can reconstruct an image of an unknown object based on high-order intensity correlation measurements of light fields.It is one of the hot topics in the quantum optics field in recent years.Correlation imaging has many advantages over traditional imaging: 1.correlation imaging is non-local;2.it can achieve lensless imaging with high imaging resolution;3.it can overcome the impact of atmospheric turbulence and scattering media in practical applications;4.the setup is simple in operation and easy to implement.This technique offers promising applications in remote sensing and other fields where high resolution is required.In the past decade,GI with the classical light sources has been realized by many different methods and most of these studies focused on the improvement of image signal-to-noise ratio,visibility and imaging speed.However,the optical intensity anti-correlation phenomena involving classical light fields to achieve a ghost image has rarely been reported.To further develop the potential application of GI,we first observe the spatial photon anti-bunching phenomenon which also called the optical intensity anti-correlation effect by manipulating the filtering thresholds in a two-arm optical setup based on the threshold filtering super-resolution correlation imaging.Through suitable choice of the filter thresholds,the minimum of the measured normalized anti-correlation function,i.e.,anti-bunching dip,can be lower than 0.2.Based on this anti-correlation effect,we present a new experiment scheme based on the traditional GI,and we call it super-resolution imaging by anti-correlation of optical intensity.After further studies,it is found that the resolution is strongly dependent on the low-pass filter thresholds.When suitable filter thresholds are chosen,the second-order correlation function is smaller than 1.It is also found that the full width at half maximum of the anti-bunching dip can be made much narrower than that of the corresponding positive correlation peak.The results show that a super-resolution negative ghost image is achieved by suitable selection of thelow-pass filter thresholds of both arms in a lensless scheme,in which the spatial resolution can exceed the Rayleigh diffraction limit by more than a factor of 2.Moreover,we have achieved super-resolution imaging with real objects based on this effect.This scheme offers a new approach to obtain a super-resolution ghost image.In the future,in combination with computational GI this technique offers great potential application value in remote sensing and other fields where high resolution is required.