Study On The Non-classicality Of Dirac-Pauli States And The Application Of Moiré Fringe In Image Encryption

The non-classicality of quantum state and the intensity correlation of light field are one of the important research topics in quantum optics.In this paper,we study the nonclassicality of Dirac-Pauli quantum states from the perspective of quantum correlation and the application of Moiré fringe in encryption and decryption of image watermark based on single-pixel imaging from the perspective of light field correlation.In the first part,we study the non-classicality of Dirac-Pauli quantum states from the perspective of joint probability distribution.we give the expression for the density matrix of Dirac-Pauli quantum states in Su(4)group,and then theoretically analyze the non-classicality of Dirac-Pauli quantum states from the perspective of joint probability distribution.The results show that the data inversion of joint probability distribution of system observations is negative which illustrates the non-classicality of Dirac-Pauli quantum states.We design experimental scheme to verify this non-classicality based on the homodyne detection.The results are helpful to understand the nonlocality of Bell type quantum state measurement.In the second part,we study the application of Moiré fringe in the encryption and decryption of printed matter from the perspective of theory and experiment.Firstly,the experimental device for the representation of encryption information is designed.And then the grating constants of encryption card and decryption card are measured by the fluorescence microscope,and the decrypted Moiré fringes is captured by CCD.The period formula of Moiré fringes is obtained by theoretical analysis.The experimental results show as the value of cosine angle between the encryption card and decryption card increases from 0.9488 to 0.9994,the period of Moiré fringes increases from 0.38 mm to 6.27 mm.Finally,we compare the measured period of Moiré fringes with the theoretical results.We find that the experimental results are consistent with the theoretical analysis.This study is of great significance to understand and expand information encryption technology.In the third part,we study whether Moiré fringe can be applied to single-pixel imaging,and the encryption & decryption of watermark.Firstly,we introduce Fourier single-pixel imaging and analyze the image encryption and decryption based on the Moiré effect.Based on the four-step phase shift method,Fourier single-pixel imaging is realized.Subsequently,we investigate experimentally the application of Moiré fringe in the encryption and decryption of single-pixel imaging and fused image watermarking.Then we reconstruct and decrypt the image of object with resolution of 128*128 pixels based on Fourier single-pixel imaging and Moiré effect.Finally,we realize the singlepixel imaging fused watermark and decrypt the encrypted watermark using the reference grating with the spatial frequency of 3.1/10 based on Moiré effect.The measured structural similarity index(SSIM)of the encrypted and decrypted images is 0.4410 and 0.2431,respectively.The results show that the image encryption and decryption in single-pixel imaging can be realized with Moiré fringe,which expands a new path for information encryption and decryption in single-pixel imaging.