Computational Ghost Imaging Based On SLM And The Experiment Under The Turbulence

As one of the frontiers in the optics field,ghost imaging has the widespread application value and the prospects for development in remote sensing imaging and target detection and other fields,owing to its non local and high resolution characteristics.Ghost imaging with rhermal light,especially computational ghost imaging(CGI)based on liquid crystal spatial light modulator,requires only a single point detector to reconstruct the target,but its its imperfect structure and systematic error leads to low signal-to-noise ratio,therefore,it is necessary to study the influence of the performance parameters of the liquid crystal spatial light modulator on the light field and ghost imaging,and to explore ways to improve the signal to noise ratio.In addition,the atmospheric turbulence will effect the image quality.At present,there is a systematic and comprehensive theoretical researches on the effect of turbulence on ghost imaging,but the experimental research is relatively few.Therefore,it is of practical value and significance to carry out the experimental study of ghost imaging through atmospheric turbulence.Based on it's structure,the model of SLM is established.The effect of SLM's filling ratio and modulation depth on the characteristics of the pseudo thermal light and the imaging quality of CGI are analysed by the method of numerical simulation.Furthermore,The pseduo thermal light with a variety of coherence length can be flexibly generated by merging the adjacent pixels due to SLM's every unit pixel modulated independently.On the basis of that,the multi phase screen method is used to simulate the atmospheric turbulence,and the influence of atmospheric turbulence on the correlation of optical field and the quality of the ghost image are analyzed.The system of CGI based on SLM is built and the experimental research of CGI under atmospheric turbulence is carried out.The pseduo thermal light with the coherent length range 30-170 ?m and the correlation peak of 1.88 is generated by loding the random phase diagram of the number merged of 4,8,16,32.Meanwhile,the experiment of CGI and analysis of SNR for the double slit with the width and the spacing of 0.3mm are done,and the experimental basis for the further improvement of image quality is provided with the analyses for the causes of experimental error.Morever,using the hot air device simulation experiment 0f the atmospheric turbulence,the experimental study of the effect of atmospheric turbulence on the imaging quality of CGI and the correlated characteristic are done.Under the atmospheric turbulence with the coherent length of 0.655 m,0.155 m,0.124 m,the correlated peak for optical field decline to around 1.6.Moreover,analysis of SNR for the three seam with the width and the spacing of 0.5mm are done and the experimental results show that the signal to noise ratio decreases with the decrease of atmospheric coherence length.and the target shfts a little,but the overall image quality is affected a little.That's to say,GCI can reduce the effect of atmospheric turbulence on the imaging quality in some extent.