Study On Influence Of Atmosphere Turbulence On Entangled Correlated Imaging And The Method To Mitigate

The quantum correlated imaging, also known as quantum ?ghost imaging', uses the properties of quantum entanglement to obtain a clear image of the object on the idler optical path, where there is no object in the path. The distributed nature of ?ghost imaging'make it a good candidate for the distributed image processing, and the distributed sensing and communication scheme.In quantum ghost imaging, a pump light passes through a BBO to produce two entangled-photon beams. One is called signal beam, and the other one is called idle beam. The signal beam passes through the object to be imaged, while there is no object in the idle path. One can get the image of the object in the idle arm by measuring the coincidence of the two beams.Based on the multiple grey scales quantum ghost imaging scheme using orbital angular momentum, we discuss the impact of atmosphere turbulence on quantum ghost imaging and the corresponding mitigation methods. Because quantum ghost imaging is closely related to the light beams, and the transmission of light is vulnerable to atmosphere turbulence, turbulence will bring the viration to beam quality, and then the imaging quanlity of quantum ghost imaging. For simplicity, we only consider atmosphere turbulence in the signal light path. The simulation and experimental results show that the image quality is affected when the turbulence exists in the signal beam path. When the atmosphere turbulence becomes stronger, the image quality gets worse. In addition, if the propagation distance is longer, the quality of the image is also worse. As the strength of turbulence increases, the PSNR (Peak Signal to Noise Ratio) gradually becomes smaller, corresponding to the decrease of image quality. For example, for two Grayscale character 'NUPT', the PSNR values reduce from 104dB to 24dB when the strength of turbulence increases from 10-16 m-2/3 to 10-12 m-2/3, which indicate that the presence of turbulence is a serious interference to the image quality.Error correcting codes can effectively reduce the impact of communication noise in information transmission.The role of the atmosphere turbulence on image quanlity can be regarded as one kind of noise to information transmission. In order to mitigate the impact of turbulence on image quality, we use the (7, 4) linear block code to encode the two gray-scale imaging NUPT before quantum ghost imaging. The simulation and experimental results indicate that, under the same conditions, the image quality improves significantly by the encoding. The encoding suppresses the impact of atmosphere turbulence on entangled quantum ghost imaging using orbital angular momentum. Simulation results also show that under certain conditions, the PSNR of the reconstructed image can reach infinity. It can be seen that channel coding is an effective method to improve the image quality of the entangled quantum ghost imaging using orbital angular momentum.