This PDF file contains the front matter associated with SPIE Proceedings Volume 6695, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

We propose an active routing wavelength switch by applying Micro-Ring Resonators (MRR). In this paper, this device is designed that the optical signals can be switched by electric signals. The electric signals modulate free carrier concentration that can change the refractive index of MRR. We can control the condition of light coupling so that one can switch light way or one wish. Therefore, we utilize the Schottky diode that can be tuned the refractive index of MRR by dc voltage. With combining MRR artfully, we can design a novel n x n switch active device based on switch architecture. Firstly, we build a 2 x 2 routing wavelength switch by MRR. Then, we use the frame of 2 x 2 routing wavelength switch to develop the 4 x 4 routing wavelength switch. The 30μm×75μm 4×4 silicon-on-insulator (SOI) wavelength switch can switch 4 wavelengths following ITU grid. With launching light from different inputs and see the output channels, the output power were simulated by Finite Difference Time Domain (FDTD) method. The simulation results illustrates the feasibility to achieve full function of optical cross connect routing wavelength switch.

Semiconductor optical amplifier (SOA) module, RSOA, SOA with mirror has become an essential component to be at the head of negative feedback amplification effect, optimum gain, and cross-gain modulation with demand for longer transmission lengths. The SOA module is expected to have an advantage of exhibiting much faster negative feedback (NF) response because distance of optical signal passing through component to component is shorten than system connected with fibers. Scattered degree and baseline line difference of eye-pattern diagrams demonstrated that NF effect can be compensated compactness and stability from band pass filter in SOA module. Modulation degree (MD) of input and output signals confirmed that SOA module with NF effect can be stabilized gain and waveguide of output signal and reduced a wave distortion as well as consistent with results in eye-pattern waveform and bit error rate (BER). All-optical switching triode with SOA module was realized in about 60 % output modulation degree at control power range of 0.01 to 1 mW. We propose that our manufactured SOA module become strong component candidate to realize all optical switching triode with NF effect for high speed optical processing in next generation.

An active integrated optical bandpass filter formed of two slanted gratings within two parallel strip-loaded slab waveguides is proposed. The frequency response of the filter is developed and it is shown, that active linear phase filters can be obtained. A numerical example for the frequency response is given.

In this work we present a simple method for the characterization of a ferroelectric liquid crystal (FLC) optical modulator and the optimization of its contrast ratio. This device acts as switchable wave-plate, where the orientation of the principal axes rotates under the action of an applied bipolar voltage. It is designed to produce a binary intensity modulation when the phase shift introduced between the principal axes is equal to 180 degrees (half wave-plate). We present a simple technique to optimize its response when the phase shift differs from this ideal value, in order to produce a highly contrasted intensity modulation. The technique involves using elliptically polarized light and requires the use of an additional quarter wave-plate in front of the FLC modulator. We represent the polarization transformations on the Poincaré sphere to provide a physical explanation of the FLC optical performance, both in the standard operational mode as well as in the optimized configuration for non-ideal phase shifts. These situations are experimentally demonstrated using a commercially available ferroelectric liquid crystal cell and two He-Ne lasers with wavelengths of 543 nm and 633 nm respectively.

Surface plasmon resonance based sensors are most useful in measuring the refractive indices of biochemicals. In such sensors a beam of light obliquely incident at an interface of glass and metallic thin film excites resonant plasmon waves in the metal if the angle of incidence or the wavelength is selected properly. The resonance conditions are changed by the refractive indices of any material in contact with the metal film. When resonance occurs the light beam is absorbed strongly. We can easily show that the phenomenon of surface plasmon resonance in such a system acts as a high quality spatial notch or band rejection filter.

We recently developed and patented the polarization optical processor (POP) and its architecture. It can be used to implement all types of digital binary devices, current and future. Binary adders are used to add binary numbers, as their names suggest. In this paper, we present the design of half and full optical binary adders using the POP architecture. A clear, simple, and easy-to-follow step-by-step design procedure is provided along with an explanation of the operation of each optical adder as a simulated bullet-train moving at the speed of light on an input-controlled preconfigured railroad system, which simplifies the understanding of the system operation.

We discuss the complex-plane representation of the polarization state of electromagnetic waves, of thin film polarization behavior, of ellipsometry, and of the polarization optical processor and binary gates. We discuss the general and special cases of representation for digital applications using two orthogonal polarization states. We also discuss two gate architectures and their operation. In addition, we present the polarization optical processor architecture and operation. The optical processor and gates do not require special logic and uses the current wealth of knowledge of digital design. They can be used to optically implement all current and future binary digital gates. The table-top realization of the gates is also briefly discussed. The optical processor and gates have much higher speeds and comparable or higher chip densities than achievable in the microelectronics industry as it is currently achieving its physical limits. In addition, the polarization optical processor and binary optical gates produce virtually no heat, which is a crucial advantage. Those are perfect solutions to the current end-of-the-road status of the semiconductor industry. Patent Pending.

A method to reduce computational costs of a factorization algorithm based on two dimensional pattern processing is presented. We develop logical operations to implement a factorization in the data compressed domain. In the method, firstly, two dimensional discrete images for data processing is compressed in accordance with the presented coding. Secondly, sequences of logical operations are executed in compression domain. Finally, desired results are obtained by extraction of the compressed data after the operations. An advantaged feature of the presented method is that computational costs can be decreased by the data compression rate.

We present a solid state range camera covering measuring distances from 2 m to 25 m and novel real-time 3D image processing algorithms for object detection, tracking and classification based on the three-dimensional features of the camera's output data. The technology is based on a 64x8 pixel array CMOS image sensor which is capable of capturing three-dimensional images by executing indirect time-of-flight (ToF) measurement of NIR laser pulses emitted by the camera and reflected by the objects in the cameras field of view. Here the so-called "multiple double short time integration" (MDSI) method enables unprecedented reliability and robustness with respect to suppression of background irradiance and insensitiveness to reflectivity variations in the object scene. Output data are conventional intensity values and distance values with accuracies in the centimeter range at image repetition rates up to 100 Hz. An evaluation of the camera's performance in typical road safety related test scenarios is subject of this paper. Furthermore we introduce real-time image processing of the output data stream of the camera aiming at the segmentation of objects being located in the camera's surrounding and the derivation of reliable position, speed and acceleration estimates. The segmentation algorithm utilizes the position information of all three spatial dimensions as well as the intensity values and thus yields significant segmentation improvement compared to segmentation in conventional 2D pictures. Position, velocity and acceleration values of the segmented objects are estimated by means of Kalman filtering in 3D space. The filter is dynamically adapting to the measurement conditions to take care of changes of the scene data properties. Flow and performance of the whole processing chain are presented by means of example scenes.

A stereoscopic 3D display delivers stereo-pair images to the appropriate both eyes. This image separating technique can be applied to the dual-views display system. This two-viewing angle display enables two users to provide different images on the screen. Meanwhile, a touch-panel is useful for a computer interface. The advantage of this touch screen is that it is easy for all users to operate intuitively. However a conventional system cannot recognize who touch the screen on a display among users. Especially the dual-views display can provide different images so as not to perceive an upside down image. In the collaborative work surrounding round table among multi-users, it is important to recognize who touched the screen and where was pointed. This paper describes the multi-users' touch-panel interface system which can recognize who touch the screen on a display.

The TOMBO (Thin Observation Module by Bound Optics) is a compound imaging system inspired by biological visual systems. The image of an object captured by the TOMBO system is composed of multiple images observed from multiple view-points. Owing to disparities between the individual images, the object distance can be measured. In this paper, we propose a novel method for 3D information acquisition using the TOMBO system. The conventional image reconstruction method on the TOMBO system assumes that a planar object is located at a specific distance. Therefore, if the actual and the assumed object distances are different, the correct reconstructed image is not obtained. To reconstruct the correct image of 3D objects, we execute the image reconstruction process with several candidates of the object distance. The distance where high frequency components are successfully reconstructed is determined as the object distance. Using the distances of all objects, we can generate a composite image focusing on the objects. Moreover, object extraction is demonstrated by using the measured object distances and the composite image. We reduce the processing time by adaptation of the processing for a GPU (Graphics Processing Unit). Experimental results indicate effectiveness of the proposed method.

A liquid crystal display (LCD) recently comes into common use. It is possible for this display unit to provide the same size of displaying area as the image screen on the panel. Thus the conventional display can show only one screen, but it is impossible to enlarge the size of a screen, for example twice. To solve this problem, we presented an enlarging method of display area using a mirror. Our extension method enables the observers to show the virtual image plane and to enlarge a screen area twice. Although the displaying region is doubled, the user cannot touch and point the extended screen in the mirror. In this paper, the authors propose a pointing interface for this virtual display, which realizes to point on a virtual area in the mirror.

A new approach is proposed for the calculation of refraction vector as a gradient of the phase shift when testing symmetrical flow with a parallel beam of light. It is assumed that the flow can be characterized by axial, conical or central symmetry. This is observed, for example, at supersonic flows around bodies of revolution. The density field between the bow shock wave and the body can be either calculated from the physics models or determined from the optical testing. The refraction vector modeling is based on polynomial representation of the radial density distributions. The confirmation of such representation is done by analysis of numerical data for various regimes of supersonic flows around bodies of revolution (sharp-tipped and blunt cones, spheres, bodies with ogive nose). Analytical formulas were obtained for refraction vector calculation in axial, conical and central symmetrical flows. For density field around a sphere in a supersonic flow at Mach number M=4, which was calculated from a physics model, refraction vector components were calculated for three different models. In the first model it is assumed that the phase change is taken place only on the bow shock wave. The second model uses a linear polynomial representation of the radial distributions based on density values calculated for the shock wave, symmetry axis and body surface. In the third model we used interpolation of the density values calculated in discrete points and least square method for polynomial representation. Results of the refraction vector calculations are illustrated by a set of graphics. The obtained formulas will be used further for the flow study using computational flow schlieren imaging technology. A recommendation is given on application of the formulas for this purpose.

This paper discusses the development of a graduate level course that covers diffraction theory and Fourier optics. MATLAB^TM is used as the basic numerical tool for these projects. In addition to providing functions for the calculation of Fresnel diffraction, the FFT command enables the calculation of the diffraction pattern of an arbitrary aperture. Relatively simple MATLAB^TM scripts are constructed to calculate the diffraction patterns of arbitrary graphics created in other programs such as text, pictures of faces, fingerprints, etc. Furthermore, the resulting diffraction patterns can be filtered and the same FFT commands be used to perform an inverse Fourier transform. This paper also describes a few demonstrations that can be used to reinforce what is covered on the projects. The demonstrations are based on a simple 4F system. The first half of the 4F system is used to show how an illuminated image changes from a reduced version of the image into a spatial frequency mapping. A Fourier plane mask is also created with small features on a chrome plated photomask. Since the features are relatively small various different types aperture can be placed on the mask.

When using Fourier plane digital algorithms or an optical correlator to measure the correlation between digital images, interpolation by center-of-mass or quadratic estimation techniques can be used to estimate image displacement to the sub-pixel level. However, this can lead to a bias in the correlation measurement. This bias shifts the sub-pixel output measurement to be closer to the nearest pixel center than the actual location. The paper investigates the bias in the outputs of both digital and optical correlators, and proposes methods to minimize this effect. We use digital studies and optical implementations of the joint transform correlator to demonstrate optical registration with accuracies better than 0.1 pixels. We use both simulations of image shift and movies of a moving target as inputs. We demonstrate bias error for both center-of-mass and quadratic interpolation, and discuss the reasons that this bias is present. Finally, we suggest measures to reduce or eliminate the bias effects. We show that when sub-pixel bias is present, it can be eliminated by modifying the interpolation method. By removing the bias error, we improve registration accuracy by thirty percent.

Multipath interference (MPI) is caused by the beating between a signal and its weak replica. In a few mode fibers, a replica of the signal propagates as a higher order mode. Since the optical path length of a higher order mode is different from the fundamental mode, it leads to interference pattern at the output end of the fiber, which degrades the system performance. In this paper, a simple method is proposed to reduce such kind of MPI effect by using a spatial filter in a 4F system. A higher order mode has higher spatial frequency components and therefore, choosing a low pass spatial filter with a suitable cutoff frequency, some part of the unwanted higher order mode can be suppressed and then MPI can be reduced. The idea is validated by simulation results.

Several approaches for increasing the speed and simplicity in computation of the digital holograms of the 3-D object have been presented with applications to real-time display of holographic images. So far, a look-up table (LUT) approach in which the pre-calculated elemental interference patterns for all possible points of the object are provided, has gained a lot of speed increase. But the greatest drawback of this method is the enormous size of the LUT. In this paper, a novel LUT method to dramatically reduce the number of pre-calculated elemental interference patterns required for computation of digital holograms compared with that of the conventional approach is proposed. Some experimental results finally reveal that the computation speed and the required memory size of the proposed LUT approach are found to be 48.8 times faster than that of the ray-tracing method and 217 times smaller than that of the conventional LUT method, respectively.

This paper presents a phase-modulated optoelectronic joint transfer correlator (PM-JTC) in which the reference image is phase encoded using a random phase function. The phase encoding is used to remove extraneous peaks from the correlation plane as well as improve the spatially efficiency of the JTC system. The reference images are phase encoded apriori making the system fast for real-time feedback. The optoelectronic PM-JTC is presented and analyzed as an effective optoelectronic correlator. The architecture of the proposed system is presented and a computer simulations of the systems are shown.

Transformation invariant image recognition has been an active research area due to its widespread applications in a variety of fields such as military operations, robotics, medical practices, geographic scene analysis, and many others. The primary goal for this research is detection of objects in the presence of image transformations such as changes in resolution, rotation, translation, scale and occlusion. We investigate a biologically-inspired neural network (NN) model for such transformation-invariant object recognition. In a classical training-testing setup for NN, the performance is largely dependent on the range of transformation or orientation involved in training. However, an even more serious dilemma is that there may not be enough training data available for successful learning or even no training data at all. To alleviate this problem, a biologically inspired reinforcement learning (RL) approach is proposed. In this paper, the RL approach is explored for object recognition with different types of transformations such as changes in scale, size, resolution and rotation. The RL is implemented in an adaptive critic design (ACD) framework, which approximates the neuro-dynamic programming of an action network and a critic network, respectively. Two ACD algorithms such as Heuristic Dynamic Programming (HDP) and Dual Heuristic dynamic Programming (DHP) are investigated to obtain transformation invariant object recognition. The two learning algorithms are evaluated statistically using simulated transformations in images as well as with a large-scale UMIST face database with pose variations. In the face database authentication case, the 90° out-of-plane rotation of faces from 20 different subjects in the UMIST database is used. Our simulations show promising results for both designs for transformation-invariant object recognition and authentication of faces. Comparing the two algorithms, DHP outperforms HDP in learning capability, as DHP takes fewer steps to perform a successful recognition task in general. Further, the residual critic error in DHP is generally smaller than that of HDP, and DHP achieves a 100% success rate more frequently than HDP for individual objects/subjects. On the other hand, HDP is more robust than the DHP as far as success rate across the database is concerned when applied in a stochastic and uncertain environment, and the computational time involved in DHP is more.

The main advantage of the double random phase encryption technique is its physical implementation however to allow us to analyse its behaviour we perform the encryption/decryption numerically. A typically strong encryption scheme will have an extremely large key-space, which will make the probable success of any brute force attack on that algorithm miniscule. Traditionally, designers of optical image encryption systems only demonstrate how a small number of arbitrary keys cannot decrypt a chosen encrypted image in their system. We analyse this algorithm from a key-space perspective. The key-space of an encryption algorithm can be defined as the set of possible keys that can be used to encode data using that algorithm. For a range of problem instances we plot the distribution of decryption errors in the key-space indicating the lack of feasibility of a simple brute force attack.

The National Ignition Facility at the Lawrence Livermore National Laboratory when completed in 2009, will deliver 192-beams aligned precisely at the center of the target chamber producing extreme energy densities and pressures. Video images of laser beams along the beam path are used by automatic alignment algorithms to determine the position of the beams for alignment purposes. However, noise and other optical effects may affect the accuracy of the calculated beam location. Realistic estimation of the uncertainty is necessary to assure that the beam is monitored within the clear optical path. When the uncertainty is above a certain threshold the automated alignment operation is suspended and control of the beam is transferred to a human operator. This work describes our effort to quantify the uncertainty of measurement of the most common alignment beam.

A new method for reliable pattern recognition of multiple distorted objects in a cluttered background and consequent classification of the detected objects is proposed. The method is based on a bank of composite correlation filters. The filters are designed with the help of an iterative algorithm exploiting a modified version of synthetic discriminant functions. The bank consists of a minimal quantity of the filters required for a given input scene to guarantee a prespecified value of discrimination capability for pattern recognition and classification of all objects. Statistical analysis of the number of required correlations versus the recognition performance is provided and discussed. Computer simulation results obtained with the proposed method are compared with those of known techniques in terms of performance criteria for recognition and classification of objects.

Predicting failure in complex systems, such as satellite network systems, is a challenging problem. A satellite earth terminal contains many components, such high-powered amplifiers, signal converters, modems, routers, and generators, any of which may cause system failure. The ability to estimate accurately the probability of failure of any of these components, given the current state of the system, may help reduce the cost of operation. Probabilistic graphical models, in particular Bayesian networks, provide a consistent framework in which to address problems containing uncertainty and complexity. Measurable nodes of the Bayesian network correspond to states of measurable parameters in the system and unmeasurable nodes represent failure of various components. Nodes for environmental factors are also included. A description of Bayesian networks will be provided and a demonstration of inference on the Bayesian network, such as the calculation of the marginal probability of failure nodes given measurements and the maximum probability state of the system for failure diagnosis will be given.

We design a high repetition rate tunable rational harmonic mode-locked fiber laser (RHMLFL). The gain media in the laser ring cavity is provided by an erbium-doped fiber amplifier. The output power of the EDFA can be adjusted to 17dBm. There are two isolators incorporated in the erbium-doped fiber amplifier to ensure the unidirectional operation of the ring laser. We modulated the high repetition rate to get the higher modulation frequency. We achieve a pulse level equalized tunable rational harmonic mode-locked fiber laser (RHMLFL). The pulse amplitude of pulse train is equalized by operating at nonlinear modulation transfer function region of active modulator in RHMLFL. Without adding any other additional predistortion components, amplitude equalized short pulses up to the fourth order rational harmonic mode-locking are successfully demonstrated for 10 GHz. One can extend such a method for various mode-locked lasers even with much higher repetition rates. In this paper, we successfully to renew the systematic structure to generate the high frequency laser output pulse train of 50GHz. Then optical pulse compressing by sixth order solitonic effect is simulated. Pulsewidth variation versus compressor length for high order solitonic effect compression is analyzed. In our previous work, the output pulse is 28 ps with repetition rate 10 GHz. The shortest pulsewidth can be demonstrated compressed below 1.53 ps using solitonic technique.

We study practical opportunities of characterizing the angular or frequency bandwidth as well as the number of resolvable elements (spots) within a two-phonon light scattering in optically and acoustically anisotropic tellurium dioxide crystal when the efficiency of acousto-optical interaction is small enough to consider these problems in the first-order approximation. Then, an approach based on the transfer function technique is applied to estimating the angular bandwidth inherent in acousto-optical cell operating in a two-phonon light scattering regime. The obtained result is compared with the data related to a one-phonon regime of light scattering in isotropic medium. Finally, the number of resolvable elements is estimated for a two-phonon light scattering regime. In so doing, the combined diagram illustrating joint effect of a triplet of such factors as the geometric limitations and the acoustic attenuation, which restrict the number of spots just in the regime under consideration, has been created for the first time.

Application of real time interferometry to NDT of the most vital parts of mechanical constructions in machinery is one of the challenging problems of contemporary engineering. The basic principle of interferometric methods is based on non-contact sensing of displacements which leads to visualization of defects, visualization of vibrated modes and stresses. In real engineering constructions almost all monitored objects have diffusely reflective surfaces, which are non mirror-like. Unfortunately a small interference contrast of diffusely reflective surfaces using contemporary interferometric technique inhibits applications of these methods to NDT. The most contemporary potentially powered method of electronic holography EH produced low contrast interferogram of diffusely reflective objects (Fig.1). It needs special algorithms, software, and time processing to improve the contrast of interference fringes. The real time monitoring, which based on surface displacements measurements under high energy impact such as laser shout, ballistic problems in military, etc. needs high contrast, real time metrology. The interferometric technique of highly effective dynamical grating has been proposed in continuous hologram development regime for monitoring of diffusely reflective objects in the real time.

A broadband microwave frequency division diplexer using photonic bandgap structure to improve the isolation and enhance output power level for tow-way electro-optic probe is presented. The microwave frequency division diplexer, where the lower pass-band is from 384 MHz to 2.58GHz and the upper pass-band is from 2.78 GHz to 8.55 GHz, is realized to connect two microwave circulators operated in different frequency band. Because of the compact size and easy to use for electrical probe, only four microwave circulators operated in different bands and three frequency division diplexer are considered to implement a planar electrical probe. Considering the ease of fabrication for wider ranges of realizable impedance values, easy to integrate with lumped-elements, small dispersion, and simple realization of series and shunt circuit elements, the coplanar waveguide structure is utilized to design and implement the proposed microwave frequency division diplexer. The simulated results of proposed microwave frequency division diplexer and experimental data of the wideband microwave frequency division diplexer with the circulators are presented and discussed in this paper.

Simplicity and low parts count are key virtues to this high voltage amplifier. Optoisolators replace complex high voltage transistor biasing schemes. This amplifier employs only 2 optoisolators, 16 high voltage mosfets transistors, 2 low voltage ones, 6 linear IC's and a score of passive components. Yet it can amplify opamp signals to 5 kV peak-to-peak from DC to sine waves up to 20 kHz. Resistor feedback guarantees the fidelity of the signal. It can source and sink 10 mA of output current. This amplifier was conceived to power ion traps for biological whole cell mass measurements. It is a versatile tool for a variety of applications.

In this paper, we propose a polarization beam splitter (PBS) for two-dimensional photonic crystal (2D PhC) self-collimation devices. By engineering the PhC dispersion characteristics, both transverse magnetic (TM) and transverse electric (TE) light can propagate collinearly in the same PhC by self-collimation phenomena. Either one or two defect regions are designed to pass the TM light and to reflect the TE light such that the two polarizations can be efficiently separated into different output ports. The finite-difference time-domain (FDTD) method is employed to assess the device performance. Polarization extinction ratios (PERs) between the two output ports are 25.4 dB and 31.8 dB for TM and TE inputs, respectively. This PBS also exhibits a large operating wavelength range (PER > 20 dB) covering all over the optical C-band and L-band. Fabrication tolerance for the radius of air holes is approximately 10 nm. Moreover, the size of the PBS is only 24 μm x 18 μm and can be even more compact for a lower PER.

The given paper studies and analyzes optical properties of semiconductor structures intended for realization of modulators. The paper considers such optical properties as absorption, transmission and refraction. The dependence of these properties on wavelength, temperature and other factors is investigated. The selection of corresponding semiconductor material for realization two versions of optical modulator, namely, for transmission and refraction is carried out.

The authors developed the revolving lantern using images of the holographic display. Our revolving lantern playbacks the virtual images which are floating in the air. These spatial images have unexpected motions and changes. The prototype imaging unit consists of the hologram, turn table and illumination system which can change the light with 1/f fluctuation so as to reconstruct various spatial images. In this paper, we describe the spatial imaging with a holographic technology and the reconstruction system which playbacks the rotating motion and various images. A hologram playbacks images. These reconstructions are generally static images. The rotating image like a revolving lantern can be produced when a hologram is spinning on the turn table. A hologram can record and reconstruct various images using the different illumination. When the illumination system changes the illumination light, a hologram reconstructs other images.

In this paper, we propose the II reconstruction technique from the hologram pattern with some image processing. That is, with II reconstruction, we can simplify the reconstruction process by eliminating the coherent light source, which is used in the conventional display holographic system. That is, computer generated holography is used as a holographic 3D image capturing. Then generated hologram pattern is segmented and reconstructed respectively. In holographic recording process, object point is recorded all over the region of hologram pattern. In other words, object point is recorded at hologram pattern at each perspective viewpoint. Therefore, when the segmented hologram pattern is reconstructed, perspective images are reconstructed. That is, multi-view images with horizontal and vertical parallax are reconstructed. These multi-view images has a full parallax are similar to sub-image array in II. Therefore, all reconstructed images are rearranged by form of sub-image array, and transformed by elemental image array. Then the elemental images are reconstructed by II technique. In the experiment, the characters of 'KW' with different depth are used as 3D objects. Then, CGH pattern of 2,000 × 2,000 pixels is generated with input and depth images, and the CGH pattern is segmented and reconstructed respectively. And the reconstructed holographic images are integrated as a sub-image array then successfully reconstructed using II technique.

Based on the principle of holographic imaging, the electroholographic display of digital holograms is performed with a liquid crystal device, LC-R 2500. The size and the position of the reconstruction image are effectively described and numerically analyzed, and the 3-D display is demonstrated by reconstructing a synthesized hologram calculated with volume slice approach. Theoretical results confirm and predict experimental results, and further research to optimize the 3-D reconstruction is suggested.

We propose a novel optical encryption approach using a lenticular lens array (LLA) as a deterministic phase modulator and the single-shot digital holographic scheme. In the proposed scheme, the input amplitude image is encrypted and interferes with the reference wave phase, which is modulated by a LLA, then recorded holographically by a digital CCD camera to form an encrypted hologram. A decryption key is obtained from the key hologram using numerical reconstruction. The image is decrypted using a digital holographic approach after which the encrypted hologram is multiplying the numerical reconstructed key for decryption. The experimental results show that only an encrypted hologram is needed. Moreover with this approach, the decryption procedure can be rapidly accomplished using a personal computer, presenting a decrypted image of satisfactory image quality. Finally the selective sensitivity of the key rotation is also investigated.

Recently, integral imaging in various applications has been studied on computerized analyzing techniques for reconstruction of the three-dimensional objects and display system design. However, conventional reconstruction technique based on computational integral imaging have some limitations in analyzing information of reconstruction and designing practical display systems. Because it has primarily been used to analyzing technique based on image processing through virtual pinhole and simple geometry excluded realistic optical properties. In this paper, we proposed the novel reconstruction technique using the micro-lens array designed and ray tracing including realistic environments and optical components in practical integral imaging system. As a theoretical background, the principle of the proposed method is described. To analyze the reconstruction system model, rays are traced by using the LightTools software. As a result, a 3-D image reconstructed by integrated rays in designed model is illustrated and some experimental results and system analysis are also presented as well.

We describe the synthesis of diffraction free beams (DFB) and quasi diffraction free beams (qDFB) with features easily tunable using a holographic techniques. The hologram plate transmittance is generated by interfering two zero order Bessel beams with non-common axis. Spatial filtering techniques are implemented by controlling the kind of illumination during the reconstruction process. The experimental results are for illumination with the same kind of illumination that the recording process, obtaining a set of diffracting free beams. One of these propagates quasi-parallel to the surface hologram. For illumination with a plane wave we obtain dark hollow beam propagating in same direction that reconstruction beam. Experimental results are shown in both cases.

Illumination functions can be modeled as multiplicative noise. Therefore, an input scene for pattern recognition is commonly corrupted by a mixture of additive and multiplicative noises. Existing correlation filters assume that multiplicative noise is either a constant factor or wide scense stationary noise. We propose a point-wise preprocessing of an input scene and consequent optimum correlation filter design. This procedure takes into account knowledge of illumination funtion. Adaptive joint transform correlator architecture is used. Computer simulation results are provided and discussed.

We discuss a method for the recording of multiple images in a photorefractive LiNbO₃ crystal which needs only a single object beam without any reference beam. The object beam is modulated by a lenticular lens array sheet to produce a set of sub-object beams. These beams are angularly separated on the recording plane but are made to overlap by light scattered light by the photorefractive LiNbO₃ crystal. The result is that only a single beam is needed to record multiple holograms. Experimental results show that four holograms can be stored in a photorefractive LiNbO₃:Fe crystal 30 mm X 30 mm X 1 mm in size at the same time. The proposed method makes it especially simple to produce one-beam write/read multiple holograms.

We proposed a novel optical geometry for holographic data storage in which a phase input pattern was involved. The input phase pattern was derived from an amplitude pattern by iterative Fourier transform algorithm. Two important parameters of reconstructed images, diffraction efficiency and image quality, were discussed and measured. Our geometry exhibited uniform holographic recording as well as uniform erasing. Moreover, the loss of light due to absorption in the input pattern was minimized. The little light loss also ensured a higher diffraction efficiency of the reconstructed image.

Absorption spectra in the range from 0.2 to 2.6 THz of chemicals such as illicit drugs and antibiotics obtaining from Terahertz time-domain spectroscopy technique were identified successfully by artificial neural networks. Back Propagation (BP) and Self-Organizing Feature Map (SOM) were investigated to do the identification or classification, respectively. Three-layer BP neural networks were employed to identify absorption spectra of nine illicit drugs and six antibiotics. The spectra of the chemicals were used to train a BP neural network and then the absorption spectra measured in different times were identified by the trained BP neural network. The average identification rate of 76% was achieved. SOM neural networks, another important neural network which sorts input vectors by their similarity, was used to sort 60 absorption spectra from 6 illicit drugs. The whole network was trained by setting a 20×20 and a 16×16 grid, and both of them had given satisfied clustering results. These results indicate that it is feasible to apply BP and SOM neural networks model in the field of THz spectra identification.

Two-center holographic recordings are performed in a strongly oxidized Ce:Cu:LiNbO₃ with three wavelengths of red, green and blue of recording beams, respectively. Three different photorefractive phenomena are observed and a critical strong nonvolatile hologram is optimally generated with the green beams and the optimal switching technique could be jointly used to obtain a nearly 100% high diffraction. Theoretical verification is given, and a prescription on optical parameters to match the green recording-wavelength for high diffraction is given.

The design of MEMS mirror with a high quality factor is essential for many MEMS applications. Our paper deals with the simulation and analysis of thermoelastic damping of the MEMS mirror based on the finite element method. Four models of MEMS mirrors are designed with various geometries. For each model, the eigenfrequency of the thermoelastic damping is investigated compared to the eigenfrequency without damping. The quality factor (Q) is discussed with a variety of geometric parameters which may affect the Q factor. The best model among the four is presented.

More than ten percent of the population in developed countries suffers from hearing impairment. Various devices have been invented to improve speech related hearing impaired people. Micro Electro-Mechanical System (MEMS) implementations of acoustical sensors are important and have potential application for future hearing aid instruments. Our paper deals with the modeling and analysis of Piezoelectric MEMS sensors for hearing aid applications. We will present MEMS based sensor and analyze the best design for hearing aid instruments. This research will be valuable for future miniature hearing aids.