Linfei Chen

Phase retrieval encryption in an enhanced optical interference by key phase constraint

In this paper, we demonstrate a security system by using optical interference and phase retrieval algorithm (PRA) techniques. The modified PRA is proposed to encode the target image into random phase distribution. Optical and digital methods can be used for decryption. By using this method, silhouette elimination is realized. In addition, due to this simplified system design, the iterative rate is improved and the optical decryption realization is easier. Validity and performance of the proposed system are demonstrated by means of numerical simulations. The system encryption capacity as to both binary and gray images is numerically investigated. Then, the decryption procedure is demonstrated by optical experiment means and the decryption result is given.

Propagation of broadband Gaussian Schell-model beams in the apertured fractional Fourier transformation systems

On the basis of the fact that a hard-edged aperture function can be expressed as finite matrices with different weighting coefficients, we obtain the analytical formula for the propagation of the broadband gaussian Schell-model (BGSM) beam through the apertured fractional Fourier transformation (AFrFT) system. It is shown by numerical examples that the intensity distribution in the plane of a small fractional order is obviously influenced by the bandwidth when the BGSM beams propagate through the AFrFT system. Further extensions are also pointed out.

Parameters for Characterizing Broadband Gaussian Shell-Model Beams Propagating in Free Space

The beam propagation factor and kurtosis parameter of broadband Gaussian shell-model beams propagating in free space are studied numerically based on the intensity moments. The effects of spectral bandwidth and spatial correlation length on these two parameters are analyzed. The beam propagation factor or kurtosis parameter of beams with broader spectral bandwidth and smaller correlation length becomes larger. The parameters of broadband fully coherent Gaussian beams is less affected by the broad spectral bandwidth than those of broadband partially coherent Gaussian beams is.