This PDF file contains the front matter associated with SPIE Proceedings Volume 10944, including the Title Page, Copyright information, Table of Contents, Introduction, Author and Conference Committee lists

See-through optical components are being intensively studied in applications such as Head-Up-Displays (HUD) and Head-Mounted-Displays (HMD). In particular, volume holographic optical elements (vHOE) have received a lot of attention due to their unique optical (angular and spectral selectivity) and mechanical (lightweight and thin) characteristics which make them perfectly suitable for use in integrated optical components like spectacle lenses and car windshields. Bayfol® HX photopolymer films prove themselves as easy to process recording materials for vHOEs. The Bayfol® HX instant developing holographic photopolymer film provides full color capability and adjustable diffraction efficiency as well as an unprecedented optical clarity when compared to classical volume holographic recording materials like silver halide emulsions (AgX) or dichromated gelatin (DCG). Besides the recording step, no pre- or postprocessing is necessary and easy mass production of vHOEs in a completely dry roll to roll process is possible. The layout of a typical Bayfol® HX film consists of a light-sensitive photopolymer layer coated onto a transparent thermoplastic substrate. This substrate is particularly beneficial, not only for easy handling of the film during holographic recording, but also for further mechanical processing steps which are required to embed the film into a finished optical component. Once holograms have been recorded and the film has been bleached with incoherent light, the Bayfol® HX film becomes inert and can be further processed in normal daylight. Moreover, the presence of a thermoplastic substrate makes the film attractive for use in manufacturing processes such as injection molding, thermoforming, casting, etc…, typically used to fabricate parts for the automotive, eyewear and ID-card industry. Being compatible with these industrial processes is an essential feature for the widespread of immersive Augmented Reality displays based on volume holographic optical elements recorded into Bayfol® HX films. In this paper we investigated the compatibility of holograms made with Bayfol® HX film with some of the integration processes typically used in the plastic and optical components industry and which are necessary for embedding the holographic films into a finished product.

Azobenzene-containing polymers have attracted much attention as photo-responsive materials owing to potential applications in optical data storage and holographic recording. In holography, azobenzene compounds doped in a polymer matrix (guest- host polymer film) or chemically attached to the polymer (co-polymer) are among the most widely used materials. Azo-polymers exhibit differing behaviors when exposed to a pattern resulting from the interference of two coherent beams. In the guest-host system, the recorded grating corresponds to a contrast of refractive index between the dark and bright areas of the film, and in the co-polymer, interference patterns lead to surface height modulation; i.e. surface relief gratings (SRGs). The latter is due to photo-induced mass movement of the polymer from bright to the dark area of the interference pattern in the direction of the intensity gradient, and the photoisomerization force is at the origin of the formation of the gratings. In this paper, we give an overview of our experiments on holographic recording in both guest host and co-polymers systems; e.g. doped and covalently attached polymers, and based on the theory of photo-induced vectorial mobility of matter, we discuss the results obtained for the co-polymer system.

Recently, we have prepared holographic reflection gratings in polymer stabilized cholesteric liquid crystals (H-PSCLCs) prepared by a 365 nm UV laser using a single prism. The H-PSCLC samples are prepared using various CLC mixtures, formulated from 2wt% photoinitiator, 5~20 wt% liquid crystal monomers, chiral dopants, and positive or negative dielectric anisotropy liquid crystals. Higher order reflection peaks, such as the second and third order reflections, are observed from the H-PSCLC samples without application of the electric field. Spectral position and bandwidth of the higher order diffraction peaks in the H-PSCLCs are tuned in blue, green, and red colors by the application of the direct current (DC) field. Tunablity of the higher order reflection band in H-PSCLCs will be discussed.

We show the design and fabrication of high diffraction efficiency, optically recorded gradient-index Fresnel lenses in a two-stage photopolymer. A design analysis reveals that lens f/# is limited by the material refractive index contrast, motivating use of recent high contrast polymers. The number of pixels required for the optical exposure is typically well beyond available spatial light modulator resolutions, motivating the use of a photolithographic mask. Thus, we present a photolithographic technique by which a single exposure into a self-developing photopolymer can directly print single custom high efficiency DOEs with freeform phase profiles, in contrast to holographic optical elements that are limited to the interference of two propagating fields. We use a dithered binary chrome mask with 9000 x 9000 pixels of 2.5 μm diameter to write lenses up to 23 mm in diameter. Lenses down to f/44 with 76% diffraction efficiency and f/79 with 83% diffraction efficiency are demonstrated.

Holographic reflection gratings formed by photopolymerization of low concentrations of liquid crystal monomers in nematic liquids demonstrate greater than 150nm of red tuning when a direct current (DC) field is applied across standard liquid crystal cell. The band position is restored when the field is removed. Diffraction efficiencies are both polarization and temperature polarization dependent. Samples are prepared using various LC mixtures, formulated from 2wt% photoinitiator, 5~20 wt% liquid crystal monomers and positive dielectric anisotropy liquid crystals. The basic tuning mechanism will be discussed, along with electric field, temperature effects on the optical performance.

We demonstrate a novel technique for in situ 3D spatial light patterning using ultrasound. By employing a customdesigned ultrasonic phased array, we form standing pressure waves that modulate the refractive index of the target medium in which light patterns are to be formed. Ultrasound pressure waves change the density of the medium locally and as a result, the refractive index is changed. Therefore, the phase front of the traveling optical waves in the medium is modulated. The interaction of light and ultrasound through the medium can be designed such that a collimated beam of light is gradually focused to multiple points deep into the medium to form arbitrary patterns of light illumination, as well as multipoint parallel imaging. These patterns can be reconfigured by changing the ultrasound interference patterns by controlling the frequency and phase of the ultrasound array elements. In this work, we demonstrate experimentally that this technique can be used to perform multi-point imaging in turbid media.

There is recently an increasing interest in holographic techniques and holographic optical elements (HOEs) related to virtual reality and augmented reality applications which demand new laser technologies capable of delivering new wavelengths, higher output powers and in some cases improved control of these parameters. The choice of light sources for optical recording of holograms or production of HOEs for image displays is typically made between fixed RGB wavelengths from individual lasers (457 nm, 473 nm, 491 nm, 515 nm, 532 nm, 561 nm, 640 nm, 660 nm) or tunable laser systems covering broad wavelength ranges with a single source (450 nm – 650 nm, 510 nm – 750 nm) or a combination. Lasers for holographic applications need to have long coherence length (>10 m), excellent wavelength stability and accuracy as well as very good power stability. As new applications for holographic techniques and HOEs often require high volume manufacturing in industrial environments there is additionally a growing demand for laser sources with excellent long-term stability, reliability and long operational lifetimes. We discuss what performance specifications should be considered when looking at using high average power, single frequency (SF) or single longitudinal mode (SLM) lasers to produce holograms and HOEs, as well as describe some of the laser technologies that are capable of delivering these performance specifications.

We present a theoretical study of diffraction gratings with twin grooves, that is, each period of the gratings corresponds to two grooves. By which it can be used to form amplitude and phase diffraction elements. The diffraction patterns of these elements are particularly interesting, due to the behavior of the diffracted orders, as well as the particularities of the envelope and its diffraction efficiency.

Metasurface is used to manipulate the optical field recently. In holography, the complex amplitude computer generated hologram can improve the quality of the reconstructed image. However, the current devices limit the application of complex amplitude modulation. Several works have been done for complex amplitude modulation by metasurface. In this work, a novel metasurface structure has been proposed to realize complex amplitude modulation. This kind of metasurface can modulate arbitrary complex amplitude. Furthermore, it has a thinner thickness, making it easier to fabricate.

Virtual reality holography (VRH) is a new art form that synthesizes the qualities of traditional hand-drawing with the unique features of holography and virtual reality (VR) art. In this paper, we compare two VR art-making applications and describe the process of transferring VR imagery to digital holography. This will show how using the specificity of various VR art-making platforms and transferring the resulting images to holography can produce original pieces of art emphasizing the qualities of these new media. Such art productions are likely to enhance the value perception of holography and VR imagery within the sphere of the art establishment.

This paper is an exploration of the numeric and visual properties of a square numerical grid containing 81 elements (“J₉ Space”). J₉ Space has been derived from the standard multiplication grid through the calculation of digital roots. Nested within J₉ Space are eight smaller square grids. A three-dimensional representation of J₉ Space has been created from the two-dimensional numerical grid, displaying the highly symmetrical properties contained within it. The three-dimensional representation is fundamentally a collection of two-dimensional triangular polygons that create a surface in three-dimensional space. J₉ Space appears to be a fundamental part of the framework of the number system and has some interesting mathematical features. This paper also summarises the recording of a three-dimensional printed model of J₉ Space as a denisyuk reflection hologram. This is an artistic impression of the model using a volume holographic technique. The author who has contributed the mathematical concept (Prashant Jadav) suggests that the use of digital roots to develop three-dimensional models from well-known mathematical tools is a new method by which to create and visualise structures within the number system.

This paper presents an upgrade of the thaumatrope, an optical toy and a pre-cinematographic animation device that was popular in the 19th century, by addition of ultra-realistic full-color holograms. It explains the working principles of this new device and evaluates its performances. To build this new kind of thaumatrope, two full-color analog transplane holograms of two different 3D objects are recorded with the silver halide color holographic material Ultimate 04 and mounted on each side of a rotating disc. The operation of the holographic thaumatrope is successfully demonstrated. When two pieces of string are attached to the disc are twirled quickly between the fingers, the disc rotates on its axis and the two transplane holograms appear to combine into one.

Augmented reality (AR) and heads up display (HUD) applications overlap images directly on the user’s field of view. To achieve that, optical components with high optical performance and versatility are required. Also, the optical elements must allow an unrestricted view of the world. Traditional optical elements as limited by laws of refraction and reflection, are not versatile, and reduce the transmittance of the devices worn by the AR user. In this paper, we discuss the transparent holographic components’ operation parameters and general optical geometries relevant for HUDs, the holographic substrata available for these applications, their performance characteristics and manufacturability.

The novel design for the compact augmented reality (AR) glasses that utilize holographic optical element (HOE) as a combiner is presented. The wide field of view (FoV) that is larger than 90°, full color and high contrast ratio (CR) are achieved based on the single layer HOE, which has the thickness of 25 μm. In order to implement compactness of AR glasses using HOE combiner, the combination of optical lenses is proposed. In this design, a chromatic aberration and astigmatism, which are caused by highly off-axis projection of the image onto HOE, and the precise wavefront reproduction that maximize the efficiency of the HOE are taken into account simultaneously. The geometrical image distortion is corrected by implementation of image pre-distortion algorithm. The interpupillary distance (IPD) adjustment is applied to compensate small eye box. Based on the design, wearable prototype is introduced. Through the experiments both on benchtop and prototype, at the distance of 2 m, large image with diagonal of 150 inches is displayed.

Head-up displays offer ease-of-use and safety advantages over traditional head-down displays when implemented in aircraft and vehicles. Unfortunately, in the traditional head-up display projection method, the size of the image is limited by the size of the projection optics. In many vehicular systems, the size requirements for a large field of view head-up display exceed the space available to allocate for these projection optics. Thus, an alternative approach is needed to present a large field of view image to the user. By using holographic optical elements affixed to waveguides, it becomes possible to reduce the size of the projection system, while producing a comparatively large image. Additionally, modulating the diffraction efficiency of some of the holograms in the system presents an expanded viewing eyebox to the viewer. This presentation will discuss our work to demonstrate a magnified far-field image with an in-line two-dimensional eyebox expansion. It will explore recording geometries and configurations and will conclude by discussing challenges for future implementation.

Digital holographic imaging is a good tool for automatic particle size and morphology measurements. One of its benefits is that flowing samples can be observed, but the focus –the reconstruction distance- should be well defined automatically to reach the best quality image reconstruction during real time measurements. Now, we present a new way to increase the accuracy of the autofocus. It is not another autofocus algorithm, but it can be used with different autofocus algorithms. Our idea was to change the input images of the autofocus algorithm. The theoretical foundation of this modification is the known connection between the numerical aperture and the depth of field. A focused target beam contains central rays with smaller and extremal rays with higher converging angles. Imaging without the central rays, the rays that increase the depth of focus will be missing but the rays which carry the details will be kept . Using only the extremal rays at the imaging we can see more clearly whether the image is in focus or not, even though it has missing information. Therefore, we reconstructed the input images of the autofocus algorithm from the hologram without the central rays. The reconstruction was made with the angular spectrum method. The central rays were eliminated with a proper frequency-filtering of Fourier transform of the hologram. This new method was tested with different autofocus algorithms, and its efficiency can be clearly observed. We used it in an in-line holographic setup, which was built to observe algae from algae cultures.

In this paper, we present a common-path digital holographic microscope for 3D particle localization. Due to the common-path geometry, our setup is self-referencing, which reduces mechanical sensitivity to environmental disturbances. Thus, the system provides high stability and phase sensitivity down to 10nm. For system testing, different particles of varying size and material are distributed in a phantom material. Holograms are recorded by a camera and reconstructed with the angular spectrum method, phase unwrapping and Zernike polynomials. Numerical propagation of a single-shot hologram to multiple focal planes allow for optimal focusing on the sample. The resulting images show the different positions and distribution of particles.

We have constructed a Holographic Scanning Microscopy (HSM) setup, which employs an optical design and a scanning unit of a commercial confocal laser scanning microscope. This arrangement helps to construct the HSM easier, but the scanning unit gives additional phase distortions modifying an object wave and introducing phase shift. We offer a way to dispose such distortions changing the way of recording holograms and reconstruction algorithm. Analyzing recorded holograms we conclude, that we need to record a hologram of flat mirror first, which would contain required information about phase distortions, and use it for reconstruction. Finally reconstruction algorithm becomes like to “coded” reference wave reconstruction algorithm. Proposed algorithm was successfully implemented and tested in MatLab.

A submersible digital holographic camera for measuring plankton and other particles is described. The camera provides underwater recording of digital holograms of water volume containing plankton followed by automatic restoration of holographic images of plankton species, determination of their sizes, shapes, and concentrations, and their recognition and classification. Particles with sizes of 200 μm and larger are analyzed. The water volume registered per exposure is about 1 L. The special features of the software for automatic information retrieval from digital holograms are discussed. Examples of application of the camera as an integral part of the hardware-software complex for field measurements are given. Prospects for application of this complex for ecological monitoring are discussed. The recognition criterion of the digital holographic camera and the data volume and the averaging time required for obtaining statistically reliable data on plankton species are also given.

In this paper, we have implemented a 3D content generation simulator based on integration of phase-only spatial light modulator (SLM) and LabVIEW software to develop a holographic stereogram printer that consists of a coherent laser, a spatial light modulator and X-Y translation stage with stepper motors. This content generation platform provides encoding of directional information extracted from rendered perspective images of real or virtual 3D object. There are mainly three parts related to the implementation for holographic stereogram printer. In the first part, “Digital content generation” phaseonly SLM will be applied to the holographic printer system by loading series of perspective 2D images for each holographic elements (hogel). Regarding this part, phase-only SLM can be converted into an amplitude modulator by adjusting the angles of the polarizer. The second part is “Control system” made in LabVIEW based platform for automatic recording of the holographic stereograms which is synthesized from previous part. The third implementation part is “Optical system” for printing of parallax-related hogels on the holographic plate. To check the performance of the developed approach, numerical simulations and optical experiments are implemented. The hogel images are sequentially exposed using the perspective images to form the whole holographic stereogram on the holographic light sensitive material.

From the first ultra-realistic 3D images in the sixties to the most recent Augmented Reality devices, the field of holography has been involved in display technology for a long time. The spectral selectivity of the hologram reflection together with the very good transparency of the holographic material make it a suitable option for some of the key optical components in smart glasses. However, these devices are still very limited by the overall optical system based on the conventional scheme Display - Optical System - Combiner. Recently, we have proposed an unconventional scheme that puts the hologram at the core of the display device. Due to its 3D nanoscale complexity, the dynamic updatable hologram display is still an unreachable goal. As an alternative, our configuration is based on a concept of switchable static holographic elements. These elements are interleaved on the surface of the display and form various groups of emissive point distributions that are phase-adjusted for given angular directions. The activation of these holographic elements produces angular planar wavefronts in the far field and the display is expected to achieve retinal projection without the help of an optical system. We present our concept and describe the development of the optical set-up used to investigate our holographic configuration. We record phase-adjusted distributions of holographic elements that are multiplexed on the surface of our sample, each distribution targeting a specific angular direction. First recording results on a holographic photopolymer are given.

Hologram is a recording in a two or three-dimensional medium. It is a form of interference pattern between welldefined coherence reference beam and the light with same wavelength arriving from an object. When the hologram is illuminated by the reference beam, the hologram reconstructs desirable wave-fronts by modulation of reference beam. The coherence of reference beam is important for recording the hologram since it determines if the diffraction pattern is made or not. Incoherent light source does not form an interference pattern. For this reason, most of the holograms are reconstructed with coherent light like a laser. However, coherent light also derives speckle noise that makes the reconstruction image unclear. So, it is meaningful to find the suitable amount of partial coherence for hologram reconstruction and receives lots of interests for a long time. But, up to my knowledge, there is no experiment that adjusts spatial coherence quantitatively. In this paper, we invent an optical method to control the amount of spatial coherence of the light source by using a digital micro mirror device (DMD). Here, the DMD takes a role of an adjustable spatial filter because the number of on-state pixels of DMD changes the amount of spatial coherence. As a result, we verify the relation between the spatial coherence and the expressible depth of reconstruction image and find the optimal amount of coherence of LED for our holographic reconstruction experiment.

Our group has developed a digital holographic interferometry camera based on an off-axis dual-beam setup. A single hologram acquired with the camera represents the phase and intensity distributions of light reflecting off the surface of an object. Our goal was to develop an algorithm that converted the acquired hologram into a 3D representation of the object. First, to determine the phase excursion of the object, a discrete Fresnel transform reconstruction was applied to a high-pass-filtered version of the hologram. The reconstructed phase map contained both the spatial carrier fringes due to the off-axis geometry of our setup and the phase information related to the object’s surface. Next, we developed a reliable 2D spatial carrier fringe removal technique that was capable of separating out the object’s phase information from the carrier fringes. Last, the object phase map was calibrated to convert the phase information to height information based on the geometrical parameters of the system. The system was evaluated using a silicon-etched lateral-axial resolution target based on a USAF design. The system achieved 33 nanometer axial resolution and sub-pixel lateral resolution over a wide field of view of more than 10 mm x 10 mm. The algorithm will enable the digital holographic camera to be used for non-destructive testing of surface morphology at nanometer scales. With repeated acquisitions, the algorithm has the potential to estimate nanometer-scale dynamic vibrations of an object’s surface.

Computer-generated hologram (CGH) has a serious problem that stereoscopic images are deteriorated by speckle noise. In analog holography, statistical characteristics of speckle noise were theorized, but it is difficult to apply the theory to CGH, which is effected by computerization such as sampling, quantization and so on. In this paper, we focused on point-based method which is one of the calculation methods of CGH and objectively evaluated the effect of the density of arrange point light sources on speckle noise. We evaluated the image quality by PSNR, considering the resolution of the eye. By objective evaluation, we confirmed the effect on speckle noise by changing the density of point light sources.

A non-interferometric phase retrieval method in the phase-modulated holographic data storage system is proposed. This method can not only avoid phase ambiguity issue with interferometric, but also increase the capacity by reducing media consumption. Iterative Fourier transform (IFT) algorithm is one of easiest non-interferometry methods. We choose to use IFT algorithm due to its compact and stable realized system and simple single-shot operation. Strong constraint conditions such as phase-only and embedded data which are known phase values of the certain positions on the encoded data page are provided to realize accurate and quick phase retrieval in the holographic data storage system. We demonstrated the phase retrieval process of the recorded 4-level phase pattern in the media experimentally. Besides, we can realize one-time Nyquist frequency recording which is the limitation of recording area by using the non-interferometric phase retrieval method and the periodicity of Fourier frequency spectrum. Therefore, the media consumption can be reduced by 35%. Eventually, we can increase storage capacity by at least 1.5 times.

Digital Holography (DH) suffers from severe degradation of the reconstruction quality due to the presence of speckles. Speckle is due to the source coherence and shows on the hologram as a multiplicative, correlated noise. Due to the larger size of the speckle grains, the lower resolution, and the worse features of the available hardware, long wavelength digital holography is more severely degraded by noise than its visible wavelength counterpart is. Non-Bayesian approaches to the denoising problem suffer from resolution loss or complex acquisition systems required to record multiple uncorrelated holograms to be averaged. Instead of providing multiple captures, these can be simulated to yield a number of reconstructions from one single hologram (generally referred to as numerical Multi-Look, ML). However, the ML improvement is inherently bounded to a theoretical limit. On the other hand, image processing has offered a wide literature on the topic over the last decades. Among the most efficient methods to reduce additive Gaussian noise, 3D Block Matching (BM3D) has emerged and it is nowadays widely used in the image processing framework. However, BM3D performance worsens in the presence of speckle and cannot be effectively applied to long wavelength DH. Here we show that the joint action of numerical ML (thought as a preprocessing filter) and BM3D in post-processing permits to overcome the theoretical limit of ML and to outperform the BM3D for the denoising of holograms. The quasi noise free reconstruction of long wavelength holograms of famous artworks will be shown.

Synthetic-aperture holography is a powerful tool for off-axis holographic imaging because it can fill the entire illumination aperture of the object under observation and provide super resolution. Normally, in off-axis holography, only the small portion of the Fourier domain containing the real hologram is filtered from the zeroth order and virtual hologram and the space where the real hologram does not fill is left null. However, in synthetic-aperture holography, a change in direction of the illumination beam changes the portion of Fourier space the hologram records and, through angular multiplexing or multiple acquisitions of these holograms, the entire Fourier space of the hologram can be filled. This is a straightforward task in holographic imaging as the filters are applied digitally. Here, we present a method based on a synthetic aperture for generating large field-of-view binary holograms using a digital micromirror device (DMD). Because of the relatively large pixel size (7.56 μm) of the DMD, only a small wavelength-dependent angular distribution (~3 deg.) for each sub hologram can be achieved. However, by changing the DMD illumination direction, a much larger sweep of Fourier space can be filled. Difficulties arise in filtering the real holographic information from the zeroth-order term and conjugate hologram as these pieces of unwanted information shift in the Fourier domain with the illumination direction. A static pinhole filter can no longer remove unwanted components. A dynamic Fourier filter was implemented based on a DMD with 4 kHz switching speed which was placed in the far-field of the hologram-producing DMD.

We have previously presented a novel spatial light modulator appropriate for use in transparent, flat-panel holographic display applications. Our architecture consists of an anisotropic leaky-mode coupler and integrated Bragg reflection grating as a monolithic device implemented in lithium niobate and is fabricated using direct femtosecond laser writing techniques. In this paper, we present a methodology for the experimental characterization of holographically-reconstructed point spread functions from sample devices.

Computer-generated holography (CGH) is the ideal 3D display technology because we can observe the reconstructed image without 3D fatigue. Holograms are made by computer simulation of light propagation. We used the point-based methods which considers virtual objects as a set of point light sources to calculate object light. Generally, in the recording process of a hologram using the point-based method, the phase of each point on the object surface is randomized in order to diffuse object light, which is called a “random phase”. A random number for implementing a random phase is called a “random phase number”. However, applying a random phase causes “speckle noise” on the surface, due to complicated interference between reflected lights. We examined the relationship between the characteristics of the random phase number and the state of the reconstructed image surface. We focused on the reflection characteristics of the reconstructed image and the speckle noise, in particular. To measure the speckle noise, we used a criterion called “speckle contrast”. In this paper, we examined the relationship between the randomness of the surface phase and the speckle contrast. We confirmed that there are random numbers whose speckle contrast depends on phase variances and random numbers whose speckle contrast does not depend on phase variances

We report on the development of a holographic camera capable of measuring nanometer-scale surface features. The system is based on a modified off-axis Mach-Zehnder interferometer and was optimized to provide high-quality interference patterns. Fast imaging was implemented with a time-gated intensified CCD camera directly facing the surface of the object. By increasing the intensifier gain, holographic images with good contrast could be captured within 1 ns. We tested the ability of the camera to measure nanometer-scale height differences using a patterned USAF target. The depth resolution of the camera was estimated to be better than 10 nm. We also found that both the object-CCD distance and the angle between the object and reference beams had significant impact on the quality of the reconstructed surface profiles. Potential applications of the camera include measurement of tissue surface displacements for non-contact photoacoustic imaging.

We show the behavior of the holographic gratings photosensitive with metallic salt, (NH4)2CrO7 at different hydrolysis concentrations of PVA (poly vinyl alcohol).The holographic gratings were recorded in real time, observing interesting changes in their diffraction efficiency, as a function of the hydrolysis variation of PVA.

Preliminary results, of holographic diffraction gratings recording are shown, which the polyvinyl alcohol mixed with a photosensitive agent salt (NH₄)₂CrO₇, and with an adequate quantity of pineapple juice, and synthetic dye. Dye as an element to increment the absorbance profile of the photosensitive material at emission line of 445nm. The diffraction gratings were recorded using laser diode at a wavelength of 445 nm.

The recording of Fourier Holograms in a photosensitive material composed of the mixture of 4% of grenetine, 1% of potassium dichromate and 95% of water is presented. This mixture is deposited in a cell formed by two slides separated by a plastic film of 0.01 mm thickness; the recording was carried out with a beam of light from an Ar laser with a wavelength of 532 nm. Some experimental results are shown.

The holograms of three-dimensional objects have been interest topics for a long time, but in the last few years other alternatives have been sought to avoid their complexities. Many of them seek to create three-dimensional effects using parallax and knowledge about stereographic vision, in other words, they use two-dimensional images.

In this paper we explore some of the benefits of calculating the wave front of three-dimensional objects, as well as several considerations that must be considered. The main ones are presented when holograms are implemented in an LSM, because of the calculation conditions and laboratory tools. Using spherical waves is a great example, a magnification along the propagation axis is produced and the objects are deformed. Therefore, it is necessary to make a study and propose changes to the algorithm that allow us to solve this situation.

Despite being fundamental complications, they allow us to explore a large amount of solutions and even consider future applications. Within this work, we seek to present some of the proposals that resolved these situations for the work teams applications.

In this paper, we propose a robust 3D image encryption scheme based on computer-generated hologram (CGH) in fractional Fourier domain. The layer-based Fresnel transform is utilized to generate one phase-only CGH, which is then decomposed into two phase-only masks (POMs) by pixel superimposed method. Encryption was realized by using the created POMs in two cascaded fractional Fourier transform domains while two decryption keys are produced in the encryption process. The cryptosystem is asymmetric and high resistance against to the various potential attacks, including chosen-plaintext attack (CPA). The proposal is supported with computer simulation results. Simulation results and security analysis verify the feasibility and effectiveness of the proposed encryption scheme.

A Head-mounted displays (HMD) for augmented reality (AR) are researched to use work support. However, it has a fatigue problem occurred by the difference of focal length between the working space and displayed image. The technique of displaying holography using an electronic device called electro-holography are expected to solve the problem, because it is possible to display images at a free depth depending on the working position. So that, holographic HMDs for AR have been studied. But, since it is consisting optical components such as lenses, a mirror and a half mirror, the size and weight of the devise become large and heavy. On the other hand, holographic optical elements (HOE) is possible to produce functions of lens, beam splitter and diffraction grating. Also, it is possible to consolidate the functions of lenses and half mirrors into HOE. In this paper, we purpose near-eye holographic display device using HOE (Egarim-PBS made by Egarim Co., Ltd.). The Egarim-PBS is consolidated the functions of lenses, half mirrors, and optical waveguide, which are all optical components to construct the holographic HMD. So that, we can perform a simpler optical structure which is only consists of an Egarim-PBS and electronic devices. Our proposed concept was proven by experimentally. The proposed system has a potential to make holographic HMD became smaller and lighter than a conventional holographic HMD.

Digital holography (DH) is a technique to reconstruct the amplitude and phase images of a sample by calculating the wavefront propagation from the interference image. Although DH enables three-dimensional shape measurement based on the phase images, axial dynamic range of a single-optical-wavelength DH is limited to less than a full or half optical wavelength due to phase wrapping ambiguity. To extend the axial range over the optical wavelength, synthesized wavelength DH has been proposed. In this method, DH is performed at two different wavelengths, and then synthesized wavelengths between them are used. However, use of a single longer synthesized wavelength degrades the axial resolution because the axial dynamic range is limited by the phase noise. To extend the axial dynamic range, one has to increase the axial range while maintaining the axial resolution of sub-wavelength. One promising approach to do it is cascade linking between multiple synthetic wavelengths with different orders. In this paper, we present multicascadelinked synthetic wavelength DH using an optical-comb-referenced frequency synthesizer (OFS). OFS is a tunable external cavity laser diode phase-locked to an optical frequency comb, and is effectively used for multiple synthetic wavelengths within the range of 32 um to 1.20 m. A multiple cascade link of the phase images among an optical wavelength and 5 different synthetic wavelengths enables the shape measurement of a reflective millimeter-sized stepped surface with the axial resolution of 34 nm.

In this work we present a preparation method of films for holographic recording. The no-toxic and cheap ingredients were used for film preparation, The films were prepared by mixing natural adhesive base on Nopal mucilage, which used as polymeric matrix, with a natural pigment as a photosensitizing agent, solution. Also, we show the experimental results of the first-order diffraction efficiency as a function of energy exposure from transmission diffraction holographic gratings, which were recorded in the films in real time.

In this paper, a uniform multiple wavefront recording planes (UM-WRPs) method for enhancing the image quality of the RGB-depth (RGB-D) image hologram is proposed. The conventional multiple wavefront recording planes (M-WRPs) based full-color computer-generated hologram (CGH) have color uniformity problem caused by intensity distribution. In order to solve the problem, the proposed method generates depth-related wavefront recording planes (WRPs) to enhance the color uniformity and accelerate hologram generation using a fixed active area. Compared with conventional MWRPs methods, the quality of reconstructed images of this method is improved significantly. The image improvement of the proposed method is confirmed by numerical reconstruction