A technique that combines the high speed and the high security of optical encryption with the advantages of electronic transmission, storage, and decryption is introduced. Digital phase-shifting interferometry is used for efficient recording of phase and amplitude information with an intensity recording device. The encryption is performed by use of two random phase codes, one in the object plane and another in the Fresnel domain, providing high security in the encrypted image and a key with many degrees of freedom. We describe how our technique can be adapted to encrypt either the Fraunhofer or the Fresnel diffraction pattern of the input. Electronic decryption can be performed with a one-step fast Fourier transform reconstruction procedure. Experimental results for both systems including a lensless setup are shown.

The performance of fully phase- and amplitude-based encryption processors is analyzed. The effects of noise perturbations on the encrypted information are considered. A thresholding method of decryption that further reduces the mean-squared error (MSE) for the fully phase- and amplitude-based encryption processes is provided. The proposed thresholding scheme significantly improves the performance of fully phase- and amplitude-based encryption, as measured by the MSE metric. We obtain analytical MSE bounds when thresholding is used for both decryption methods, and we also present computer-simulation results. These results show that the fully phase-based method is more robust. We also give a formal proof of a conjecture about the decrypted distribution of distorted encrypted information. This allows the analytical bounds of the MSE to be extended to more general non-Gaussian, nonadditive, nonstationary distortions. Computer simulations support this extension.

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The performance of nonlinear joint transform correlators (JTCs) are experimentally tested with respect to in-plane and out-of-plane rotation distortions. Optical experiments are presented for both linear and nonlinear joint transform correlators. The robustness of these systems to rotation distortions is investigated. The results show that nonlinear JTCs perform similarly to linear JTCs in the presence of out-of-plane rotation distortions, but that nonlinear JTCs are more sensitive than linear JTCs to in-plane rotation distortions. However, it is well known that nonlinear JTCs have the desirable properties of illumination tolerance and discrimination sensitivity. To reduce the sensitivity of nonlinear JTCs to in-plane rotation distortions, the nonlinear joint power spectrum is multiplied by a circularly symmetric Gaussian function. This is equivalent to applying a Gaussian filter to the nonlinear JTC output. The experimental results show that using such a Gaussian filter provides nonlinear JTCs with similar in-plane rotation tolerance to that of linear JTCs.

A novel photon-based proton model is developed. A proton’s ground state is assumed to be coherent to the degree that all of its mass-energy precipitates into a single uncharged spherical structure. A quantum vortex, initiated by the strong nuclear force, but sustained in the proton's ground state by the circular Unruh effect and a spherical Rindler horizon, is proposed to confine the proton's mass-energy in its ground state. A direct connection between the circular Unruh effect, the zitterbewegung effect, spin, and general relativity is proposed. Such a structure acts as an uncharged zitterbewegung fermion, and may explain neutrino mass. A ground-state proton's central zitterbewegung fermion is assumed to be surrounded by a halo of charge shells of both signs. Virtual photon standing waves are assumed to synchronize the inner shell with the central zitterbewegung fermion. The charge shells are proposed to be associated with isospin and proton g-factor. There are only two model inputs—proton mass and quantized electronic charge—and just one adjustable parameter. The adjustable parameter, reduced only by about 0.4% from an initial estimate, provides the proton’s experimentally determined magnetic moment to arbitrary precision. The resulting modeled proton charge radius agrees very well with the 2018 CODATA value. Magnetic moment and charge radius are calculated algebraically in a manner easily understood by undergraduate physics students. This proposed ground-state proton model could be falsified by future experimental proton charge radius estimates, and could be considered a low-energy approximation to a full quantum chromodynamical proton model.