The optimum conditions for preparing, recording and processing of Methylene-Blue Sensitized Dichromated Gelatin depend on some atmospheric parameters of laboratory where the operations are carried-out and the optimum value of different parameters appropriate to different conditions must be determined by experiment. Int his paper these conditions as well as the quality control of DCG plates and the diffraction efficiency of holographic gratings registered on these plates are reported.

The paper describes the application of vitreous chalcogenide semiconductors (VCS) thin films in high-resolution holographic recording. The processes of selective chemical etching of VCS films investigated as depending of the exposure conditions.

A major problem for surface-relief hologram is lack of enough diffraction efficiency for different applications. Different approaches have been proposed to achieve this target including multi-level step lithography. The multi- level lithography need highly accurate mask making and etching process in order to make stepwise grating pitch profile to enhance the first order diffraction efficiency. Other methods such as gray level exposure etc. also use phase grating profile in process control. This paper proposes to utilize both gradient index thin film coating and etching processes to enhance diffraction efficiency. Moreover, this study investigates the theoretical feasibility of proposed grating structure which was made of a gradient index layer etched to form rectangular shaped binary profile pitches. This structure may be easier and more cost effective to do than multi-level lithography process. A theoretical study using rigorous coupling theory employed to do analysis was developed. The result was presented to show the effect of gradient index layer on the performance of a grating diffraction. Theoretical model shows the potential for using gradient index layer structure to enhance diffraction of surface-relief hologram.

We propose the efficient optical perfect shuffle (PS) interconnection using block-quantized binary phase holograms (BQBPH) method for making the grating of high efficiency which is important in implementing optical PS. The pattern of grating in BQBPH was obtained by computer simulations using iterative method and the diffraction efficiency of designed grating was about 67 percent through BPM simulation. The grating was fabricated using laser beam writer and diffraction efficiency was 47 percent by experimental test. We implemented optical PS using the fabricated grating and showed that optical experimental output patterns were good agreement with PS output patterns.

We propose a simplified model to calculate the computer generated rainbow hologram fast. The rainbow hologram is very practical to display 3D images because the images can be reconstructed by white light. Since the rainbow hologram has horizontal parallax only, less computation is required compared with full parallax transmission holograms. In the proposed method, we can simply generate the final hologram from intermediate data, whose total number of samples can be less than one tenth of the final hologram. This intermediate format makes fast computation and effective storage/transmission possible. It can be done only multiple and additional operation to convert the intermediate data to the final data. Therefore, it is possible that a hardware implementation to the electro-holographic display or printer. In this paper, we discuss both theory for the simplified model and experimental results of white light reconstructed images. Full color holograms are also discussed.

Optical birefringence of volume photopolymer holograms could be applied as polarization elements and an important compensated device for display. In this paper, an analysis of the optical birefringence in volume photopolymer hologram is given. This characteristic analysis is mainly based on the Kogelnik's coupled wave theory. These characteristic properties for index modulation and optical birefringence in hologram formation are theoretically analyzed with respect to the parameter of diffraction efficiency, film thickness, angular and wavelength selectivity. This paper is also considered the holograms in slanted and nonslanted structures. Results of the characteristics of optical birefringence is provided an approach to realize as an optical compensation. This study shows that the property of negative birefringence in volume photopolymer will give a newer application in liquid crystal display technology.

Analysis of reflection gratings in As-S thin films photodissolved with silver for a rectangular profile is presented. This analysis is performed by solving the scalar wave equation and by matching the amplitude of the electric and magnetic fields at the boundary of the grating with the external medium. In order to find the amplitudes of the reflected waves, an infinite system of coupled wave equations should be solved. This system of the differential equations can be put in a matrix form and the matrix of coefficients can be obtained using a Gauss elimination method. Our numerical results show that for a pure reflection grating, only the zero transmitted and reflected orders have appreciable efficiency, when the diffraction efficiency is plotted versus the grating strength parameter. Angular response of the diffraction efficiency shows that at each angle of incidence, the diffraction efficiencies of the transmitted and the reflected waves add to unity for each diffraction order. Our results show that the diffraction efficiency increases as the concentration of silver increases in the arsenic sulfide layer.

The application of holographic optical elements (HOE) has been extended to the field of biomedicine. Holographic optical elements, with the ability to change the light distribution, have been implemented into a variety of optical devices and biomedical instruments. Novelty features of holography-based technology include: 1) 3D image display; 2) Thin holographic films act as highly effective light- traps; 3) Films have high transparency when acting as antireflection coating; 4 Films have significant enlarged surface area due tot heir surface relief; and 5) Randomized structures act as a diffuser that homogenize incoming light into a controlled spatial pattern. Optical display and biomedicine applications utilizing these optical properties based on HOE were investigated.

We propose a flexible 2D bit-parallel optical interconnect method for use in large-bandwidth inter-processor communications. We have studied various possible input/output coupling schemes, and have modeled power loss and resolution degradation mechanisms associated with the schemes. We have also performed experiments to investigate the power efficiency and imaging resolution characteristics of the interconnect schemes.

Highly polarization-selective holographic elements can be achieved with suitable designs. The presented holographic polarization-selective elements are compact and light- weight, and the feature of normally incident and output coupling provide better flexibility and easier alignment for system applications. With suitable designs and arrangements, these elements can be combined to implement star couplers to distribute equal optical power from each input channel to all output channels. In addition, based on our holographic polarization-selective elements with electro-optic halfwave plates, holographic polarization-dependent and polarization- independent optical switches are introduced. The structures to use these switches in various compact 3D multistage interconnection networks for reconfigurable interconnections and in self-healing rings for network service restoration are presented.

A novel holographic method of making hard copies of a three- dimensional image from the computer data, the dot array rainbow hologram (DARH), is introduced and analyzed. The DARH is recorded dot by dot using a 1D liquid crystal panel and our proposed projection algorithm, and can reconstruct 3D image with horizontal parallax under white light illumination. The principle of making DARH and holo- animation are discussed. Preliminary experimental result showing effectiveness of this method is also presented.

A new kind of kinetic holography is introduced in this paper. The kinetic model and the kinetic effect are generated by a computer. This kind of holography has been used in many important security holograms called 'animated holograms'.

The investigation has revealed the reason which the environmental stability of methylene blue sensitized dichromated gelatin (MBDCG) holograms can only by improved by coating some polymer solutions. An efficient method of resisting humidity into MBDCG holograms is reported in this paper. The method used the viscid liquid of pure polystyrene of low degree of polymerization as coating materials. Based on this coating, the diffraction efficiency of coated MBDCG holograms exposed to high humidity environment is not observed significant changes during observation.

In this paper, we have discussed how to use a TV-computer system in holographic interferometry. With Ar⁺ laser as a light source, BSO crystal as a recording material, TV- computer as a detector, holographic interference pattern is automatically scanned, recorded and judged. Not only contour map is reconstructed, 3D plot is also graphed. With BSO crystal, hologram can automatically in real-time be developed. As an example we have measured the deformation of a plate under a stress by real-time holographic interferometry of 4-interferograms method. With respect to common holographic setup, TV-computer system can automatically control shifting the phase of reference beam, exposing holograms, scanning, recording and judging interferograms.

In this paper, a new storage approach of color films by means of a single-wavelength laser and SLMs is presented. A color film is illuminated with a beam of incoherent white light but filtered into red one. Then a frame on the film is imaged on a CdS liquid crystal SLM. The red coherent light of a He-Ne laser projects on the SLM as a reading light. So the output light of the SLM is also a red coherent light that carries the image information of the red incoherent light. By replacing filters with green and blue ones, three images of red coherent light can be produced step by step. A rainbow holographic recording geometry is arranged to store the three coherent light waves. Therefore, an image frame of the color film is stored in a rainbow hologram which can be preserved forever.

In this paper, a new kind of security hologram using an encoded reference wave is introduced. The hologram is produced with the interference of an encoded reference wave and a convergent object wave. The focus of the convergent wave can be reconstructed only by the illumination with a duplicate of the original encoded reference wave. Because the verification pattern is simply s spot peak rather than an image pattern, this kind of security hologram is suitable for machine inspection. A scheme of machine inspection by using this kind of security holograms is described.

The method of multifactorial orthogonal design is proposed in the paper to decide the diffraction efficiency (DE) comprehensively. The orthogonal table is designed to major manufacturing parameters mentioned above. The variance analysis is carried on. The conspicuous factors on DE are obtained, and the optimal technological conditions are established. In addition, regression analysis is also studied to the conclusion, the calculating and experimental results are in good agreement. A fit rate of 81 percent is obtained.

Binary optical elements have been developed well over the past few years. This article gives the results of studies on the application of binary optical elements in four-channel two-frequency interferometer. To correct mechanical errors of measurement in real-time, a beam-splitter is needed to split laser beams to measure different parameters. In this interferometer, binary optical elements are employed as a beam-splitter and deflector instead of prisms. The volume and weight of the interferometer are reduced a lot by using them. These elements are easy to regulate and work well. The piece of glass is a 2D Dammanm grating, which split the original beam into four beams with equal intensity. Another glass plate with four gratings is used as deflector to make these beams to run parallel to each other. The parallelism of split beams is less than 15 arc seconds. In the experiment, no observable phenomenon of depolarization was found. It means that binary optical elements can be employed in two-frequency interferometer. The main disadvantage of binary optical elements is its low diffraction efficiency. When the beam pass through binary optical elements, about eighty percent of its amplitude is lost.

An optoelectronic interconnection based on volume holographic coupling elements located on a light-guiding glass plate has been realized by exposure at the wavelength of 630 nm. A light beam is reconstructed at the same wavelength and guided by total internal reflection inside the glass plate. The contraction coefficients and the refractive index change of the thin film of red sensitive photopolymer have been measured. Coupling gratings with an accurate period and a slanted angle have been designed.

This paper presents a new method of encrypting the laser holographic label for anti-counterfeiting. It is called 'random stripes intervening method'. This method has been successfully used in encrypting the holographic label for anti-counterfeiting. The features of this method are that it is almost impossible to imitate the labels after using this method, and it would not cause any extra price to the product, and it could be sued in the 'front line' of anti- counterfeiting.

A novel equivalent optical path polarized light interference microscopy has been designed which provides two attractive properties of the perfect bright-field background techniques. This microscopy is suitable for detecting the phase objects and microdamage spots or inclusions in the transparent optical materials.

A new method generating diffraction-free beams is proposed. Design scheme is based on Fresnel-Krichhoff diffraction principle. An investigation of the diffraction efficiencies and the transverse intensity distribution on the focal plane of the designed annular focus zone lenses is presented. Computer based simulation results are presented. Its transverse intensity distribution is of stability and of property of the zeroth order Bessel beam. These properties are with no relation over an appreciable propagation distance. The zeroth order Bessel beam have with narrow beam radii, larger intensity. The design device can also produce ring light source. It translates the light of a laser diode into a high intensity narrow width zeroth order Bessel beam. Diffraction-free beams can be used in making VLSI, medical knives, laser prints, memory read write head, high precision collimation,high precision measure. It can be widely used in industrial field and military fields.

A new expression for the complex amplitude distribution of an off-axis point source is derived based on 'quasi-Fresnel approximation', which is more accurate than that by common Fresnel approximation. The possibilities of making astigmatic optical element holographically are discussed, and a topic holographic lens is recorded and imaging beams are measured, which are closed to the theoretical values. Using the new expression it is easy to explain the on-axis astigmatism in holographic imaging.

A novel method for producing durable fused silica self- interference phase grating photomasks is described in this paper. The gratin pattern is formed into AZ-1350 photoresist by 325nm He-Cd laser optical holographic exposure and is transferred to a thin metal layer via focused ion beam lithography, then reactive ion etching in CHF₃/O₂ plasma is used to etch the fused silica substrate. Inspection performed by scanning electron microscopy shows that fabricated silica phase masks are perfect and no reactive deposition is formed int he grating grooves.

The near-field holographic interference patterns of phase masks irradiated by excimer lasers is analyzed in details theoretically in this paper. The interference intensity patterns produced by periodic phase masks are calculated using scalar diffraction modeling with various assumptions of mask parameters.

In this paper, the design theory of a computer-generated quadruple focus holographic lens is described. The holographic lens is required to have the identical diffraction performance for the four focuses. Because the fringe pattern of the hologram can be expressed with mathematical equations, the principle of computer holographic interferogram is adopted. We present an area division method for the design of multi-focus computer- generated holograms. The mathematical model, computing process and an example of design ar given int his paper.

Deep etched diffractive optical elements could acquire some significant properties, for example, deep etched Fresnel lens could be used as fast lens, deep etched blazed grating has high dispersive index. So it is a new subject of binary optics. In this paper, a new kind of element, deep etched multi-phase level fractional Talbot grating is presented. Compared with common fractional Talbot grating, it has the property of high fill factor.

Two phenomena which are different form traditional observation results in holographic imaging are reported in this paper. They are double virtual images and so-called virtual pseudomorphic image. It is shown that here exists an appropriate condition for Fresnel hologram upon which two virtual images can be reconstructed. And it is also shown that the virtual pseudomorphic image could not be physical, but only psychological.

The method of designing of CGHOEs in which the Fourier transform is adopted has been developed.The operation will be simplistic. The desire for recording materials can be decreased. The practical requirements are reached.

Zn, Fe:LiNbO₃ crystal, with fine photorefractive properties, has been grown by Czochralski technique. Its response time was measured to be about ten seconds, the diffraction efficiency to be higher than 70 percent. Employing Zn, Fe:LiNbO₃ as a holographic record media, another photorefractive crystal Cu:KNSBN as a self-pump phase conjugate mirror, the double-exposure interferometry has been studied in this paper.

This paper gives the example of making infrared wire grid polarizer used in 8 to approximately 14 micrometers wave range by ion beam milling. We have measured and calculated the transmissibility and polarizability of the polarizer. The results have been analyzed and compared with those derived from the theory. it is illustrated that we can get uniform and better quality polarizer by using this method.

Comprehensive theoretical studies of the effects of light transmission characteristics of multimode optical fiber bundle on hologram have been made in this paper. Object image plane holograms are recorded by image-carrying optical fiver bundles of different fiber core diameters.

Light scattering constant and scattering cross sections of human white blood cells were studied and measured. The functional relationship of cell number density concentration hematocrit and the intensities of scattered and transmitted was deduced. It is distinctive in this study that the optical parameters are represented by the logarithm of the ratio of scattered intensity to transmitted intensity, also by the logarithm of transmitted intensity as well.

A new holographic technique has been used to make a compact, accurate and reliable POS scanner. The holo-window technology that permits compact POS scanner optical scanning horizontal plan while maintaining excellent performance in changing the scan direction, equalizing the scan velocity and collecting the signal light. The holo-window design and fabrication the HOE for such a compact POS scanner are described in this paper. Additionally, this new horizontal side scanning with very large depth of field, allows the grocery items scanned horizontally thus eliminating the commonly known carpal tunnel syndrome, hand injuries of the checkers. This newly designed POS scanner has been recognized by industry as the standard for the future POS scanning configuration.

A method to calibrate an optical phase shifter used for digital speckle pattern interferometry was developed by using a Michelson interferometer and electronic charge- coupled device array camera. The phase shifter was constructed by attaching a mirror to an axially-poled lead zirconate titanate piezoelectric actuator. The results showed that for the particular piezoelectric actuator used, an applied voltage of 240 volts shifted the phase by 2 (pi) , and the application of increments of voltage in steps of 60 volts from 0 to 240 volts generated four steps of equal phase shift. The tests indicate that the phase shifter is well suited for digital speckle pattern interferometry, due to the good linearity of the phase shift with applied voltage.

A new method is presented for synthesizing arbitrary grey level intensity patterns based on phase contrast imaging. The concept is grounded on an extension of the Zernike phase contrast method into the domain of full range phase modulation. By controlling the average value of the input phase function and by choosing appropriate phase retardation at the phase contrast filter, a pure phase to intensity imaging is accomplished. The method presented is also directly applicable in dark field image synthesis. Preliminary experimental results are demonstrated for binary-only phase modulation.

Parallel aligned liquid crystal-spatial light modulator (PAL-SLM) has been applied to an optical interconnection system by a CGH technique. In the system, the PAL-SLM is expected to have electrically addressed capability. We have developed a CRT coupled PAL-SLM that can be electrically addressed. For that purpose, the CRT have been designed and evaluated on a fluorescence spectrum and an afterglow time of a phosphor to suit PAL-SLM features. And we have also evaluated two coupling methods between the CRT and the PAL- SLM ; one is a relay lens coupling method and the other is a fiber optic plate (FOP) coupling method. Consequently, it can be concluded that a combination of a red phosphor with a long afterglow time and the FOP coupling method is suitable for the CGH application. We can get a fine and noiseless CGH reconstruction image by using this module.