## What is/are Phase Masks?

Phase Masks - A stochastic gradient descent algorithm and a Gauss-Newton algorithm are developed and compared for their ability to recover the phase masks for previously reported point spread functions.^{[1]}The phase masks make the optical transfer function drop significantly, and digital restoration must be used to obtain a clear image with a largely extended DOF.

^{[2]}The dependence of the transverse displacement of Airy beams on artificial propagation distance in phase masks is investigated with no motion of imaging apparatus.

^{[3]}It has been demonstrated that any unitary transform of spatial modes can be implemented by passing through a succession of phase masks with free-space propagation in between, and the key is to inversely design the phase distribution of each phase mask.

^{[4]}To characterize the role of scattering, we have developed a forward model based on the beam propagation method and established the link between the macroscopic optical properties of the media and the statistical parameters of the phase masks applied to the wavefront.

^{[5]}Both amplitude and phase masks are considered for hexagonal and square arrays of mask openings.

^{[6]}, many phase masks are evenly spaced in sequence, light scattering is assumed to occur only at the masks.

^{[7]}We present the results of the experimental formation of contour vortex fields, based on optics of spiral light beams with diffractive phase elements using binary amplitude—phase masks and phase holograms with symmetric and asymmetric grating line profiles.

^{[8]}Phase-modulating thin-film devices (phase masks) made of amorphous silicon nitride are commonly used to generate a wide range of different beam shapes.

^{[9]}001) between mean separations of phase masks generated from the WHPC and HHP filtered phase images.

^{[10]}We also experimentally prove that it can generate a shaped beam similar to the beam generated by the axisymmetric dielectric microhelical cone structure, which can keep well by imposing the phase masks of the structure onto a spatial light modulator.

^{[11]}After developing the theoretical basis of SODI, we demonstrate the second-order resolution improvement experimentally using phase masks and binary amplitude masks with only 8 frames.

^{[12]}Second, instead of using random phase-only masks, a number of phase masks retrieved from 2D patterns derived from the rows of the designed Hadamard matrix are used to record the measured intensities.

^{[13]}Thereafter, one of the channels is considered as the input amplitude image while the other two are used as phase masks, one in the spatial and the other in the frequency domain.

^{[14]}Commonly, special UV photosensitive fibers and phase masks inscription technique are used for an FBG fabrication.

^{[15]}, spectral filters, prisms, or phase masks, our neural net correctly identifies static and mobile emitters with high efficiency using a standard, unmodified single-channel configuration.

^{[16]}In this work, the modulation is introduced by phase masks in the shape of a subset of Jacobi-Fourier polynomials.

^{[17]}The problem of calculating the electromagnetic field of directional radiation passing through a system of amplitude-phase masks arises in many studies.

^{[18]}

## double random phase

A well-known technique for optical image encryption is the double random phase encoding (DRPE) technique, which uses two random phase masks (RPMs), one RPM at the input plane of the encryption system and the other RPM at the Fourier plane of the optical system, in order to obtain the encrypted image.^{[1]}We present the numerical simulation results of the proposed phase masks employed in the double random phase encoding system.

^{[2]}Another is decomposed into two phase masks, which are placed into the input plane and transform plane of double random phase encoding, respectively.

^{[3]}

## Random Phase Masks

In the proposed encryption scheme, the fingerprint is served as secret key directly, and the random phase masks generated from the fingerprint using secure hash algorithm and chaotic map are just used as interim variables.^{[1]}In this case, the plaintext is scrambled by ART and then encoded into a noise-like interim image using ptFrFT with two random phase masks as private keys obtained by HCS.

^{[2]}Furthermore, the encryption characteristics are enhanced by utilizing the 2D-FrFT angles and orders as extra encryption keys in addition to double random phase masks.

^{[3]}Then, AQW are used to generate two random phase masks which can operate the preprocessed image and the DCT image, respectively.

^{[4]}The transformed bit planes are combined together and then encrypted using random phase masks and fractional discrete Meixner moments.

^{[5]}Conventional 3D photon counting DRPE can quickly encrypt the data by using the 4f optical system and random phase masks with enhanced security because the 3D photon counting technique is used.

^{[6]}We use the fractional convolution, nonlinear operations and random phase masks (RPMs) in order to encrypt images.

^{[7]}Herein, an optical cryptosystem based on Fourier ptychography (FP) with double random phase masks is proposed.

^{[8]}In the place of traditional random phase masks, the proposed cryptosystem uses statistically independent deterministic masks in L1 and L3.

^{[9]}A well-known technique for optical image encryption is the double random phase encoding (DRPE) technique, which uses two random phase masks (RPMs), one RPM at the input plane of the encryption system and the other RPM at the Fourier plane of the optical system, in order to obtain the encrypted image.

^{[10]}Random phase masks are important technical elements for realizing holographic memory systems that enable high density recording.

^{[11]}An optical cryptosystem via Fourier ptychography with double random phase masks is proposed.

^{[12]}The main objective is to propose a new DRPE-based image verification scheme by replacing random phase masks (RPM) with efficient chaotic phase masks (CPM) which are dependent on an input image.

^{[13]}We propose a novel asymmetric optical image encryption scheme using two random phase masks (RPMs) and lower upper decomposition with partial pivoting (LUDP), in which the encryption process is different from the decryption process and encryption keys are also different from decryption keys.

^{[14]}The piecewise linear chaotic map (PWLCM) is used to generate key images and random phase masks, and to determine DNA encoding rules.

^{[15]}The nonlinearity of the JTC along with the five security keys given by the three random phase masks and the two digital fingerprints of the two users allow an increase of the system security against brute force and plaintext attacks.

^{[16]}In this paper, the fractional Fourier operators, the random phase masks and the nonlinear operations of amplitude and phase truncations are utilized to encrypt and decrypt images.

^{[17]}

## Two Phase Masks

Finally the original color channel can be directly separated into two phase masks: one is a combination of gamma distribution and biometric phase keys and the other is a modulation of the combination by the original color channel.^{[1]}A compact, single-channel interferometer is developed by spatial-random multiplexing of two phase masks for producing axial planes suitable for diffusing one of the two co-propagating waves for the study of light propagation through thin diffusers.

^{[2]}The voice information is distributed among two phase masks and a security image using the enhanced iterative approach.

^{[3]}Another is decomposed into two phase masks, which are placed into the input plane and transform plane of double random phase encoding, respectively.

^{[4]}

## Inhomogeneou Phase Masks

In STOC the time-varying inhomogeneous phase masks are used to modulate the light incident on the sample.^{[1]}In STOC the time-varying inhomogeneous phase masks modulate the incident light.

^{[2]}In STOC, the phase of light in one of the interferometer arm is modulated in time with inhomogeneous phase masks displayed sequentially on the SLM.

^{[3]}

## Coded Phase Masks

The lenslet array in the regular SHWS is replaced with an array of coded phase masks, and the principle of coded aperture correlation holography (COACH) is used for wavefront reconstruction.^{[1]}By using a certain type of coded phase masks, we increased the phase measurement certainty up to a factor of 5 compared to a conventional, open-aperture interferometric approach.

^{[2]}Two coded phase masks are displayed, one after another, on the SLM to modulate the projected scattered field and the two corresponding intensity patterns are recorded by a digital camera.

^{[3]}

## Binary Phase Masks

In addition, it is possible to independently store, retrieve, and manage the encrypted digital holograms without affecting other groups of the encrypted holograms multiplexed using different sets of binary phase masks, due to the orthogonality properties of the Hadamard matrices with high autocorrelation and low cross-correlation.^{[1]}We experimentally investigate the performance of co-optimized hybrid optical–digital imaging systems based on binary phase masks and digital deconvolution for extended depth-of-field (DoF) under narrow-band illumination hypothesis.

^{[2]}

## Metamaterial Phase Masks

The stability of the dual-frequency operation is achieved thanks to different types of functionalized surfaces involving the micro-fabrication of integrated III-V absorbing metallic masks or metamaterial phase masks by e-beam lithography.^{[1]}The stability of the dual-frequency operation is achieved thanks to different types of functionalized surfaces involving the micro-fabrication of integrated III-V absorbing metallic masks or metamaterial phase masks by e-beam lithography.

^{[2]}

## Vortex Phase Masks

These instruments typically make use of vector vortex phase masks, and at short near-infrared wavelengths, the phase masks tend to be spatially variant liquid-crystal-polymer-based diffractive waveplates.^{[1]}We investigate the advantages of imaging individual cones using vortex phase masks of different topological charge.

^{[2]}

## Compensated Phase Masks

Our parallel algorithm, including the online speckle recording process and the offline compensated phase calculation process, allows it possible to calculate the compensated phase masks for generating several focused spots at different predefined positions at one time, which is quite timesaving.^{[1]}Furthermore, the parallel algorithm we present makes it possible to obtain a series of compensated phase masks, which could be used to generate a series of focused spots at different locations.

^{[2]}

## Shaped Phase Masks

In this work we propose the use of Jacobi-Fourier shaped phase masks to produce sharp and clear images for optical systems affected by random and varying aberrations.^{[1]}Jacoby Fourier polynomial shaped phase masks (JFPM) have been shown to be potentially effective for extending the depth of focus in wavefront coding technique.

^{[2]}

## Structured Phase Masks

red, green and blue are first separated and modulated with three different structured phase masks.^{[1]}Nano-structured phase masks offer intriguing possibilities in electron-beam shaping.

^{[2]}

## Optical Phase Masks

This can be important for post-processing of existing data, or for the design of optical phase masks to engineer PSFs optimized to achieve high contrast, angular resolution, or astrometric stability.^{[1]}The most common and simple approach to beam shaping is by the use of optical phase masks.

^{[2]}

## Holographic Phase Masks

Nevertheless, holographic phase masks – i.^{[1]}A new technology that includes a flexible holographic recording system using photo-thermo-refractive (PTR) glass is demonstrated for creating so-called ‘holographic phase masks’ or HPMs.

^{[2]}

## phase masks generated

In the proposed encryption scheme, the fingerprint is served as secret key directly, and the random phase masks generated from the fingerprint using secure hash algorithm and chaotic map are just used as interim variables.^{[1]}001) between mean separations of phase masks generated from the WHPC and HHP filtered phase images.

^{[2]}