We propose what we believe is a new method for color image encryption by use of wavelength multiplexing based on lensless Fresnel transform holograms. An separated into three channels: red, green, and blue, each channel independently encrypted. The system parameters transforms random phase masks in are keys decryption. optical coding configuration with multichannel implementation an optoelectronic architecture single-channel presented. can be added iteratively employing the transforms....

We propose a new method for image encryption based on Hartley transforms that is real transform and can be realized by spatially incoherent or coherent illumination. The proposed optical implementation Michelson-type interferometer in which the pure random intensity distributed at plane encryption. Computer simulations prove it possible. A hologram also given described to resolve sign ambiguity problem would encountered reconstruction.

A discussion and a cryptanalysis of the optical phase-truncated Fourier-transform-based cryptosystem are presented in this paper. The concept an asymmetric cryptosystem, which was introduced into image encryption scheme based on Fourier transforms 2010, is suggested to be retained encryption. new method attack also proposed simultaneously obtain main information original image, two decryption keys from its cyphertext, public modified amplitude-phase retrieval algorithm. numerical results...

The general analytical formula for the propagation of power-exponent-phase vortex (PEPV) beam through a paraxial ABCD optical system is derived. On that basis evolution intensity distribution such in free space and focusing investigated. In addition, some experiments are carried out, which verify theoretical predictions. Both experimental results show beam's profile can be modulated by topological charge power order PEPV beam.

We analyzed the propagation characteristics of intensity a vortex beam after it passes through twisting phase. It was found that doughnut-like pattern would separate into several bright and dark fringes. The number fringes between two spots is equal to topological charge (TC) beam. Meanwhile, varies with sign TC. Based on this property, we proposed convenient method measure TC by observing its passing This detection technique mainly based use phase, effect parameters in phase demonstrated...

Optical twists are the rotation of light structures along beam axis, which can be caused by quadratic twist phase a partially coherent field. Here, we introduce new class beams whose spectral density and degree coherence tend to rotate during propagation. Unlike previously reported twisted Gaussian Schell-model beams, this family rotating is constructed without framework rotationally invariant cross-spectral functions. Thus, these have different underlying physics exhibit distinctive...

We report analytic formulas for the elements of e 2 X2 cross-spectral density matrix a stochastic electromagnetic anisotropic beam propagating through turbulent atmosphere with help vector integration. From these changes in spectral (spectrum), degree polarization, and coherence such on propagation are determined. As an example, quantities calculated so-called Gaussian Schell-model isotropic homogeneous atmosphere. In particular, it is shown numerically that this class, unlike beam, its...

A new mathematical model called "controllable dark-hollow beams" is introduced to describe hollow beams. The central dark size of this beam can be controlled easily by the order N and parameter epsilon. An analytical formula derived for propagation a controllable through paraxial optical system, some numerical calculations are carried out. Some important characteristics beam, such as factor kurtosis parameter, studied in detail, their variation rules versus epsilon presented plotted.

Analytical formulas for the elements of 2x2 cross-spectral density matrix a kind stochastic electromagnetic array beam propagating through turbulent atmosphere are derived with help vector integration. Two types superposition (i.e. correlated and uncorrelated superposition) considered. The changes in spectral degree polarization such an generated by isotropic or anisotropic Gaussian Schell-model sources on propagation determined use analytical formulas. It is shown numerical calculations...

The earlier proposed interference-based encryption method with two phase-only masks (POMs), which actually is a special case of our method, quite simple and does not need iterative encoding. However, it has been found recently that the security problems cannot be directly applied to image due inherent silhouette problem. Several methods based on chaotic algorithms have remove problem by postprocessing POMs, increased computation time or led digital inverse in decryption. Here we propose new...

We propose a method for generating focal beams with special intensity distributions using radially polarized vortex in 4Pi configuration. A spherical dark-hollow beam and hollow array can be obtained by topological charge of m=1. dark channel generated m=2. The length the well-defined is about 30λ. These interesting are useful optical trapping manipulation.

The asymmetric cryptosystem, which is based on phase-truncated Fourier transforms (PTFTs), can break the linearity of conventional systems. However, it has been proven to be vulnerable a specific attack iterative when two random phase masks are used as public keys encrypt different plaintexts. An improvement from cryptosystem may taken by relocating amplitude values in output plane. In this paper, methods adopted realize modulation image. first one extend PTFT-based asymmetrical into...

A double-image encryption technique that based on an asymmetric algorithm is proposed. In this method, the process different from decryption and encrypting keys are also decrypting keys. nonlinear process, images encoded into amplitude cyphertext, two phase-only masks (POMs) generated phase truncation kept as for decryption. By using classical double random encoding (DRPE) system, primary can be collected by intensity detector located at output plane. Three POMs applied in safely public...

We propose a simple amplitude-phase retrieval attack free cryptosystem based on direct to phase-truncated Fourier-transform-based encryption using random amplitude mask (RAM). The RAM that is not saved during the provides extremely high security for two private keys, and no iterative calculations are involved in nonlinear process. Lack of enough constraints makes specific algorithms unusable. Numerical simulation results given testing validity proposed approach.

We introduce a novel class of planar, quasi-homogeneous Schell-model source for producing far fields with optical lattice average intensity patterns and derive the corresponding beam conditions. The array dimension, lobes profile, periodicity can be flexibly tuned by changing correlation parameters field. It is also found that, an appropriate choice parameters, radiant may possess flat-topped patterns.

Caustics occur in diverse physical systems, spanning the nano-scale electron microscopy to astronomical-scale gravitational lensing. As envelopes of rays, optical caustics result sharp edges or extended networks. structured light, characterized by complex-amplitude distributions, have innovated numerous applications including particle manipulation, high-resolution imaging techniques, and communication. However, these encountered limitations due a major challenge engineering caustic fields...

It is shown how the phenomenon of correlation-induced spectral changes generated on scattering a polychromatic plane wave spatially homogeneous random medium may be used to determine correlation function potential medium.