The analysis of the results of the study in the field of organic recording media for making of frequency-selective optical memory is presented. Among these media are polymolecular films based on cyanine dyes and photoinduced merocyanine molecules of photochromic spirocompounds capable to form-aggregates. Besides, media manifesting hole photoburning at low temperatures are reviewed too because of their prospect of the development for frequency-selective optical memory with extreme information capacity.
Proc. SPIE 3055, Diffraction efficiency of photopolymers: use of Gaussian recording beams and real-time monitoring, 0000 (28 February 1997); doi: 10.1117/12.267695
A measurement technique making it possible to obtain dynamical recording characteristics of photopolymer materials, i.e. the diffraction efficiency versus exposure time and irradiance, from a single holographic exposure using Gaussian recording beams is presented. The material under investigation is the DuPont photopolymer solution HRS- 150X001-20-35.
The effect of low-powered polarized light on magnetic characteristics of ferrimagnetic garnet films has been studied by means of polarization microscope. The spectral, polarization, temperature and intensity dependences of room- temperature photomagnetic effect have been obtained. Correlation of magnetization and domain structure changes with parameters of the film and illuminated light are discussed in terms of developed model. Mechanism of the effect is connected with a photoinduced strain of the crystal lattice.
Proc. SPIE 3055, Thin films of vitreous chalcogenide semiconductors for long-duration storage of information, 0000 (28 February 1997); doi: 10.1117/12.267717
The changes in optical properties of thin films of vitreous chalcogenide semiconductors in the pro cess of long-duration storage are studied. The feature of films composition influence and their preparation on the long-duration process are established.
Chalcogenide glass layers are well-known optical recording media. Amplitude, phase and even polarization of light signal may be recorded with high resolution in real time scale or with additional etching. Details of recording mechanisms are still under discussion especially concerning the leading role and type of induced structural transformations. Possible types of these mechanisms spread from the photo-(thermo) crystallization to the different amorphous-amorphous structural transformations. Most of them may be essentially changed by natural or artificial restrictions of the transforming region dimensions and it was the idea of our investigations.
The optical memory on materials having the properties of electron trapping is a new direction at development of information storage and rewrite. Currently are pursued investigations directed on creation of a new type recording medium with the opportunity of information rewrite by optical methods as well as a medium for heteroassociative memory in optical neural systems. Primarily as such medium are used alkaline-earth metal sulphides activated by two rare-earth elements. When creating the memory on materials with electron trapping on the basis of alkaline-earth sulphides there arises a number of difficulties: (1) these materials are chemically unstable, especially they are subject to the action of water vapors; (2) films prepared by electron-beam evaporation technique have a polycrystalline structure with grain sizes in the order of 20 nm what has an essential influence on the signal-to-noise ratio at information reading. The main objective which is pursued by us consists in investigating the optical properties of new synthesized materials having the electron trapping properties which are characterized by chemical stability and are easy manufacture at preparation of amorphous structures. We have also recommended to use CaO (MgO) doped with Eu, Sm. It has known, that the optical stimulated luminescence (OSL) obtains in CaO. But OSL appears in the special prepared structures with defects. For this aim there are some methods: thermochemical reduction or radiation processing by electron beam. Besides that the OSL obtains only by nitrogen temperature (77 K).
Three-dimensional vector diffraction analysis for optical disc systems is described. The geometrical form of information pits and tracts is simplified to rectangular form. The disc surface and side wall of pits are perfect conductive. We considered two physical model of the pits: (1) in the bottom of pits the partial waves of rectangular waveguide satisfy impedance condition; (2) bottom of pits are connected to semi-infinite dielectric space. In the first case we obtained two-dimensional integral equation for electrical field in upper end of pit. In the second case we obtained two integral equation for upper and lower pit ends. The diffraction of laser beam by information pits was regarded in Fourier optics approach. We use the most exact theory of diffracted vector field to evaluate Fourier transform function for Gaussian beam. This approach gave us possibility to investigate the diffraction fields in the case of the lens with big aperture and small linear size. The obtained mathematical algorithm was applied then to the study of diffraction linear polarized Gaussian laser beam by disc information surface and to the diffraction laser beam by small rectangular aperture in infinite shield. The digital results showed that to obtain accuracy for integral characteristic of fields less than one percent it is necessary to take eight Fourier members for every coordinate on every pit end.
Self-defocusing of ordinary and extraordinary laser beams have been investigated in cadmium sulfide semiconductors in the near-band-edge absorption region. First it has been shown experimentally, that effects of the anisotropy nonlinear refraction induced by charge carriers created by single photon absorption is described whole set components of the third order nonlinear susceptibility tensor. New type of transverse optical bistability with increased amout of feedback due to nonlinear anisotropy was demonstrated.
Proc. SPIE 3055, Films of chalcogenide glasses as media for the fabrication of diffraction elements and holographic recording of information, 0000 (28 February 1997); doi: 10.1117/12.267734
Inorganic resist on the base of chalcogenide glasses As40S60-xSex were investigated as the media for phase-relief holograms formation. It was obtained that As40S60-xSex thin-film negative resist characterized by maximum light sensitivity and extensive linear section of characteristic curve. The high-effective flat diffraction gratings with sinusoidal groove profile were recorded as test-holograms.
Pairs of thin films of semiconductors and metals forming the eutectic by laser irradiation during optical recording are developed. These materials have better properties of evaporation, long lifetime and are not toxic.
Proc. SPIE 3055, Mechanism for recording and erasing optical information by laser radiation on an SiO2-(Co+Si)-SiO2-Si multilayer structure, 0000 (28 February 1997); doi: 10.1117/12.267686
We present in this paper results of investigation of optical properties of SiO2-(Co plus Si)-SiO2-Si structures under laser treatment with Q-switched YAG:Nd and carbon dioxide lasers. The photo-thermo-chemical reaction of Co with Si has a threshold character. No changes in optical properties of (Co plus Si) mixture was observed up to intensities of carbon dioxide laser radiation 2 MW/cm2. At larger intensities the reflection coefficient R decreases from 70% to 45% with increasing of the intensity up to 8 MW/cm2. When this multilayer structure is irradiated with Q-switched YAG:Nd laser with radiation intensity from 14 MW/cm2 to 53 MW/cm2, the magnitude of reflection coefficient returns to its initial value 70%. It means that the information recorded by carbon-dioxide laser is erased. Calculations of the temperature field during irradiation with carbon-dioxide and YAG:Nd laser showed that the phase transition from mixture (Co plus Si) to CoSi2 caused by irradiation with carbon-dioxide laser results in recording of information, whereas the thermal impact caused by irradiation with YAG:Nd laser results in amorphization of CoSi2 and erasing of information.
Proc. SPIE 3055, Structure-relaxation-induced peculiarities of the holographic recording in amorphous As2S3 films, 0000 (28 February 1997); doi: 10.1117/12.267687
The results of the experimental study of holographic recording in a-As2S3 films are reported such as exposure and intensity dependencies, spatial frequency dependence. Several peculiarities are found including recording intensity threshold, nonmonotonical intensity dependencies, nonlinear exposure curves, the change of the spatial frequency response due to films aging. These peculiarities are explained in terms of phenomenological model which is based on the simultaneous action of the photostructural changes and the relaxational structural changes.
Device is intended for the experimental obtaining of intensity distribution in the section of beam diffracted from pre-grooved surface. It simulates the work of laser read-out systems as at the reproduction as in the static state. It is possible to estimate the influence of optical system parameters on the values of reproduction-, servo- signals and signal/noise ratios. This device may be used for the measuring of relief micro-object dimensions as well as for the optimization of optical channel and optical disc parameters and for the design of optical discs with the higher information density.
Essential peculiarities of the readout procedure of the optical disc with the dye active layer are determined by the coating process technique and by the active layer optical parameters. Such active layers have a mixed amplitude-phase microstructure. There is an inherent problem in continuous- groove servo system that embossed and information pits degrade servo signals generated by grooves, and thus also degrade fast and reliable read/write. To solve this and related problems, the present paper uses a two-dimensional scalar diffraction model to simulate optical servo signals such as the tracking error signal (TES) and the sum information signal (SIS). The present paper describes the optimum geometry of an optical disc with embossed and read- only data pits and continuous grooves and also optimum thickness of active layer.
It is known, that multilayer interference structures -- dielectric mirrors, narrow-band filters, etc., which contain the chalcogenidic glassy semiconductors (CGS), can be used as photorecording media and secondary carriers in systems of record, storage and processing of information. It is advisable to use the focused beam at optical record for increase of speed and realizations of high resolution. In this message some phenomena in light-sensitive multilayer interference filters (IF) under influence of light beams at various geometry's and conditions of polarization are described.
Proc. SPIE 3055, Alternating magnetization research of rare-earth-transition metal films by magneto-optical method, 0000 (28 February 1997); doi: 10.1117/12.267691
Offered work describes the results of feature investigation of GdFe and TbFe films magnetic reversal by magneto-optical method. The electrical outline of magnetic field formation for pulsing hysteresigraph is described. The opportunity of described hysteresigraph use for research of magnetization, demagnetization and alternating magnetization processes of films in external fields from 10 to 6000 Oe is shown. The examples of analysis of films magnetic structures on magneto-optical loop kind of hystersis are adduced. The turn of magnetizations both magnetic subsystems in GdFe films along external magnetic field was observed. The opportunity and conditions of films reversible alternating magnetization realization without change of magnetic field direction is shown. The opportunity of this phenomenon use for creation of thermo-magnetic record carriers with direct rewriting of information at constant external magnetic field is shown.
Bacteriorhodopsin (BR) is a special photosensitive material having biological origin. BR is characterized by reversible photochemical cycle with rapidly changing transitions (the time of the transition till 3 ps) and more long living transitions (the time of the transition till 5 ms). Moreover, selecting the giving length of the wave and time of the exciting and introducing of certain chemical additives makes possible the photochemical cycle blockage, i.e. blockage of the long living excited states of this material, as a result that provides its using in the creating of the registrating dynamic media of the optical information.
A work by a computer with input analog signals like a sound and graphics has some features in contrast to work with other forms of information. And one of the very essential differences is a data transfer continuity. Pauses when being transferred a sound or stoppages of frames take place owing to warm backup in up-to-date compact hard disk drives (HDD). HDD suspends its work and gives read-write heads an opportunity to adjust themselves to changed thermal conditions. Every time this procedure breaks a data transfer continuity in a computer. It is known, that the famous manufacturer such as 'MICROPOLIS' (from 1993) and 'SEAGATE' (from 1994) produce some specialized (with cache memory) HDD with capacity up to 9 Gb to audio and video applications. As one of such problem solutions there is proposed a new volume memory mechanism based on using of the energy thin structure in organic molecular crystals such as anthracene, tetracene, and pentacene. These crystals are solid state systems and have more complicated structural organization than inorganic, covalent andion crystals. The modern level of organic chemistry development give almost unlimited opportunities of such crystals synthesis.
The paper contains the results of investigation of new registration medium based on thin films for optical data storage. Thin compositive polymer films doped with Sb and Pd are the high effective registration media with thermal mechanism of digital recording by means of pulsed laser irradiation of visible and infrared spectral regions. The investigation of the optical properties had been carried out by laser ellipsometry method and Raman spectroscopy in these films.
Proc. SPIE 3055, Information storage duration on optical carriers based on metal-polymeric recording media, 0000 (28 February 1997); doi: 10.1117/12.267696
The results of physical properties changes for metal- polymeric films at their long-term operation and storage are presented. The results of accelerated aging tests which allowed us to evaluate the lifetime of information carrier are shown. The influence of information recording mechanisms on its storage time on optical cylindrical information carrier is established.
An infrared and visible absorption spectra of aggregates with metallic spherical particles (size of about 10 - 30 nm) in dielectric matrix are theoretically studied. Calculations of the effective dielectric constant of such systems have been carried out in electrostatical approximation by considering the concentration expansion up to second power of f(f is a volume fraction occupied by spheres) with the pair multiple interaction induced by external field been taken into account exactly. We have found that the frequency dependencies of an imaginary part of dielectric function and absorption coefficient in plasma resonance region for a single particle have two peaks that are shifted into longwave and shortwave frequency regions in relation to the known Lorrentzian absorption peak corresponding to the dipolar surface plasma mode of isolated spheres.
The self-regulation neurosystem of preliminary treatment of screen image was developed on principle of bildening and functioning which is analogous to the structure of man's vision canal. Such functions of man's vision canal as self- adaptation and self-tuning were taken into account. These functions are intrinsic also to other of man's sensual canals.
Proc. SPIE 3055, Equivalent models of neural networks and their effective optoelectronic implementations based on matrix multivalued elements, 0000 (28 February 1997); doi: 10.1117/12.267699
The theory and equivalental models of neural networks based on equivalence operation (non-equivalence) of continuous and multivalued neural logic are considered. Their connection with metric of metric-address spaces are shown. Normalized equivalencies of vectors with multilevel components are determined. Equivalental models for simple network with weighted correlation coefficients, for network with adapted weighing and double weighing are suggested. It is shown, that the network model with double weighing (adapted and correlation coefficients) being most generalized can also conduct the recalculation process of networks to two-step algorithms without calculation of connections matrix. Equivalental models require calculations based on vector- matrix procedures with equivalence operation and can be realized on vector-matrix equivalentors with space and time integration. The apparatus implementations of models with productivity of 108 divided by 109 connections/sec and neuron number 256 and more are suggested.
The neuro-network equivalent models of multiport optical associative memory (MOAM) with different training rules are considered. The given models use image weighting in order to increase memory capacity while storing highly correlated images. The algorithms of the model's implementation are also suggested. The mathematical background of all these models are basic operations equivalence of continual logic and Boolean operations of coincidence, vector-matrix, and matrix-matrix procedures with those basic operations. The generality and acceptability of equivalent models application for the description of MOAM and neuro-networks (NN) with different coding methods and image representation are shown. All this creates the possibilities for the creation of digital as well as analogue memory. The results of modeling exemplified by the storage and recognition of all the letters of English alphabet are considered. Means of MOAM and NN based on these models implementation are suggested and discussed. The performance of the models is 1010 divided by 1011 connections/sec, they do not require the storage of matrix interconnections multilevel weights. These weights are formed in the course of calculations while recalculating networks, and the pattern images but not weights are stored in a single memory. Basic devices for MOAM and NN implementation on the base of equivalence models are matrix-matrix equivalators (MME).
There were developed and studied new irreversible storage media based on the anodically etched and oxidized porous silicon and on nanocrystalline composite silicon films prepared by reactive pulsed laser deposition for pulsed laser recording for the first time.
Special class of all-optical holographic associative memories with a nonlinearity in the filter domain is represented. Natural nonlinearity, just a nonlinear part of a holographic recording, lies in the basis of auto- and heteroassociative processes. It is shown, that the here developed class of quadric hologram-based associative memories is the widest generalization of a holographic matched filter technique including informative properties of ghost-image holography, Vander Lug's correlator, so-called 'second-order holography' using photorefractive oscillators, and nonlinear holographic associative memories based on resonator-like architectures. Potentialities of a quadric hologram-based associative processor to archival data storage and implementation of optical interconnections are discussed.
Proc. SPIE 3055, Diffraction of Gaussian laser beam by three-dimensional grating of dielectric spheres, 0000 (28 February 1997); doi: 10.1117/12.267703
To overcome the limitation of the current memories some authors developed method for storing data throughout a volume of memory material using two-photon absorption effect. In this work we represent the three-dimensional vector analysis of diffraction laser beam by the simple model of this volume data storage. We represent the volume data storage as homogeneous dielectric in which three- dimensional grating of spheres with complex (epsilon) , (mu) are located. To evaluate scattering field of partial wave we used Lorenz-Mie theory. The total scattering field is sum of partial scattering fields and some small addition field of re-radiation. The addition field of re-radiation was evaluated in first approach of perturbation theory. The investigation results were used for the determination of recording information limits into the memory material.
The possibility of rainbow hologram registration on a base of photothermoplastic recording media is shown. The single- layer photothermoplastic compositions consisted of polymer photoconductor-poly-N-epoxypropylcarbozole and co-polymers of epoxypropylcarbozole with alkylglytsidyl ethers sensitized to the visible by novel electron acceptors of fluorene series were investigated and used for the rainbow hologram recording. For rainbow hologram recording of diffuse object we used such photothermoplastic materials that ensure a possibility of (3-4)-fold intensification of geometrical surface relief with diffractional efficiency h greater than or equal to 4-5% without metallization at suitable signal-noise ratio. The metallization of such holograms permits us to increase h up to 20 - 30%. Both composition of photothermoplastic materials and registration regime (charging, heat development) with using multifold geometrical surface relief intensification were optimized.
The aim of the present study is an investigation of ellipsometry based reading out method from multilevel optical recording medium. This method is based on the variation of ellipsometrical parameters of laser beam under reflection from the multilayered (or multilevel) recording medium. A mathematical simulation of the above mentioned recording medium was performed and the program for calculation of ellipsometrical parameters variation was developed under reflection from multilayered information carrier. The calculations for As2 Se3-As2S3 pairs of materials and a correspondent sample of four- layered information carrier were performed.
The report presents an experimental evidence and theoretical background for the development of new correlation devices, which initially aimed at information take off in one or several points where the sensors of the detecting system are located. The main feature of this approach is to employ the multibeam interference energy redistribution of the correlation signal in to the predetermined points of in information take off. Such discrete representation ensures considerable gain in energy and does not distort the signal to be examined.
Proc. SPIE 3055, Quantum-statistical restrictions on the information transmission rate in narrow-band photonic and electronic channels, 0000 (28 February 1997); doi: 10.1117/12.267708
On the base of entropy defect principle the models are considered of narrow-band quantum communication channels and compared with the classic description of information channels. The classic model is shown to be applicable in a wide range of channels' parameters. But in the case of fermionic channels it is necessary to take into account that values of signal power and channel capacity are limited. These maximum values can be approximated by the simple expressions. Bosonic channels are free of these limitations. The rough quantum model of narrow-band bosonic channels gives too high values of capacity at low communication rate as compared with accurate one.
Proc. SPIE 3055, Design of optical thin film structures for information recording based on spectrophotometric data, 0000 (28 February 1997); doi: 10.1117/12.267709
The work describes a method of determination of complex refractive index spectra of thin films and computation modeling of optical properties of multilayer recording media. The examples of inorganic films spectra are given, the comparison of results of modeling with an experiment is conducted. The installation, enabling to conduct spectrophotometric measurements of light-sensitive recording materials in weak monochromatic flows, excluding changes of material during measurement is described.
At present there exist many methods of preparing film structures on an inner surface of cylindrical elements by vacuum technology. They are designed for evaporation of metallic, oxide and other surface layers mainly and cannot practically be used for the formation of optical layers using multi-component, strong dissociative materials. Therefore we have developed the flash evaporation method using fiber as a film-forming material. This method allows us to obtain defect-free, x-ray amorphous, uniform over the thickness recording layers from multi-component strong dissociative materials.
Now information protection on personal carriers (for example, cards) from an unauthorized access (UA) is a very important problem in connection with wide introduction of proper automatic systems for information processing in different spheres of human activity. These are financial, medical and information services, an access to restricted units and so on. There is proposed to use physical parameters of the special coating part (so-called restricted zone) to information protection on optical carriers (laser cards). There is formed restricted zone on the surface of the recording coating of a laser card. The unique information about every laser card to creating a protective passport from UA is obtained by readout of defects parameters.
The description of a method for optomechanical sound reproduction from Edison cylinders the distinctive feature of which is recording the surface profile of the cylinder sound track with its subsequent conversion into sound by means of a computer is presented. With the purpose of decreasing the destructive influence of reproduction system on the cylinder surface the recording the surface profile of a sound track is carried out at rotational speed smaller by a factor of 20 - 30 of that one at which was executed the information recording on it. The realization of a proposed method allowed to reproduce information recorded on cylinders with minimal action and to obtain a high quality of a reproduced signal.
It was revealed experimentally that at some thicknesses of thin layer deposited onto glass substrates occurred the abrupt transformations in the radiation spectrum formed as a result of the diffraction of laser beam canalized by this structure on open exit end. The computering analysis of structure spatial spectrum demonstrated that mentioned changes were caused by energy transformation of discrete spectrum mode into continuous spectrum mode that was manifested by abrupt phase changes of modes.
Proc. SPIE 3055, Control system for optical recorders using cylindrical carriers: problems and decisions, 0000 (28 February 1997); doi: 10.1117/12.267714
Optical cylindrical carriers are cheap and simple. At the same time, the requirements to units and systems of recorder using such carriers are increased. The problem of achievement of standard control accuracy at initial difficult conditions was solved and some original decisions were found.
Proc. SPIE 3055, Synthesis of an optoelectronic system for tracking (OEST) the information track of the optical record carrier based on the acceleration control principle, 0000 (28 February 1997); doi: 10.1117/12.267715
The problem for construction of control algorithm in OEST the information track of the optical record carrier the realization of which is based on the use of accelerations is considered. Such control algorithms render the designed system the properties of adaptability, feeble sensitivity to the system parameter change and the action of disturbing forces what gives known advantages to information carriers with such system under operation in hard climate conditions as well as at maladjustment, workpieces wear and change of friction in the system. In the paper are investigated dynamic characteristics of a closed OEST, it is shown, that the designed stable system with given quality indices is a high-precision one. The validated recommendations as to design of control algorithms parameters are confirmed by results of mathematical simulation of controlled processes. The proposed methods for OEST synthesis on the basis of the control acceleration principle can be recommended for the use at industrial production of optical information record carriers.
One of the most important problems in modern laser medicine is the determination of system response on laser treatment. Reaction of living system is significant during many kinds of laser procedures like surgery, therapy and biostimulation. Our study was aimed to optimize laser exposure using feed-back fiber system for intravenous laser irradiation of blood (ILIB). This system consisted of helium-neon laser (633 nm, 5 mW) with coupled fiber unit, photodetector and PC interface. Photodetector signals produced due to light backscattering were storaged and processed during all blood irradiation procedure. Significant time-dependent variations were observed within 9-15 min after beginning of treatment procedure and were correlated with number of trials, stage and character of disease. The designed feed-back system allows us to register a human blood response on laser irradiation to achieve better cure effect.
Holographic camera which makes high quality holograms using a thermoplastic material on a glass substrate is described. The holographic camera automatically monitors exposure and development. The image on glass plates can be exposed/erased many times. With optimal exposure and development -- 3000 write/erase cycles are possible before noticeable degradation of image. The system is very compact and has light weight.
Anti-jamming processing of optoelectronic detector signals, ensures control system invariance to change of laser power, dispersion of reflection from layer and presence of information pits. Logarithm amplification of photodetector currents stabilizes steepness of their characteristics at change of laser power (more than 10 times) and factor of reflection from surface (3 times). Besides, sections of tracing signal are chosen, which are located in intervals between information pits and free from recording. This measures increased focusing and tracking accuracy 2 - 3 times.
The way of laser beam control is offered at optical recording, at which the exact moving to next and subsequent tracks is realized without interrupting of tracking. Error signals are modified in such a manner that stimulate it to change a position of stable balance from one track to another one and so on. The advantage of this moving beam control is accuracy and independence of drive parameters.
Proc. SPIE 3055, Three-axes precision digital accelerometer with fiber optic sensor for measuring superlow accelerations, 0000 (28 February 1997); doi: 10.1117/12.267721
In the article as an example of development three-coordinate precision accelerometer for super-small linear accelerations measurement an opportunity of increasing of measurements' precision has been illustrated by usage of pulsing fiber optical sensors (FOS). FOS used in accelerometer with time- pulsing modulation of output signal provides a unique technical parameters of an accelerometer. It allows us to recommend it to be used in space engineering (for space flying apparatus (SFA) accelerations measurement affected by brake action of the rests of planets' atmospheres (for orbital SFA), 'solar wind' pressure (for interplanetary SFA), geodesy, geology (for gravitational fields intensity measurements or their small deviations).
Proc. SPIE 3055, Data bank of the acousto-optic refractometric functions of a novel complex halogenide for IR and UV deflectors, 0000 (28 February 1997); doi: 10.1117/12.267722
On the basis of the opticorefractometric regularity (OR) the possibility of a computer design of an acousto-optical Q- factor (AOR) data bank is shown. Taken as an example the novel complex halogenides the investigations have been carried out. The obtained results in comparison with well- known from world scientific works are given. It is shown that such approach is very important for producing IR- and UV-deflectors.
Proc. SPIE 3055, Data bank of ORXalpha: optimization of germanium pniktido-chalcogenide compounds for ablative recording of information, 0000 (28 February 1997); doi: 10.1117/12.267723
In the present paper the algorithms and programs have been proposed for computer design of data bank based on optico -- refractometric regularity (OR) and X(alpha ) -- approach while calculating photoinduced changes (PC) in complex pniktido-chalcogenides to be used for ablative information recording.
Proc. SPIE 3055, Fundamental requirements of energy consumption and dissipation for data conversion in optoelectronic communication networks, 0000 (28 February 1997); doi: 10.1117/12.267724
On the base of entropy defect principle the model of ideal opto-electronic converter is considered. Main restriction on information transmission in opto-electronic communication networks is shown to be caused by the data conversion process from optical part of the net to electronic one. Though, in principle, under certain conditions some amount of energy necessary for data conversion from optical communication channel to electronic one can further be recovered.
Two original designs of mirror image rotator systems (IRS) on base of five plane mirrors with planar perpendiculars for panoramic plane pivots of the infrared solar spectrographs and circular review systems are considered. Comparison of conventional three-mirror IRS with proposed ones showed advantages of the latter, such as: mirror sizes' decreasings (in 1.8 - 2 times), decrease of the longitudinal and radial dimensions of the system (in 1.3 - 3 times) and optical pathlength for axis beam (in 1.25 - 3 times).
Single crystals of general molecular formula ABX3, where A is a monovalent ion (A+) equals Tl+, Cs+), B is a divalent element (B2+ equals Cd2+, Pb2+), and X equals Cl/Br, belong to an important class of halide crystals that attract attention of investigators due to their interesting properties and various phase transition mechanisms. Some structure sensitive and acousto-optical parameters were obtained from the experimental results. The temperature behavior of the dielectric permittivity and conductivity of these insufficiently investigated crystals in the range 250 - 550 K corresponds to a normal behavior of ionic crystals. It was found that the correlation took place between a tolerance- factor and some structure sensitive parameters of the above- mentioned crystals.
Super small fiber probe of laser Doppler velocimeters and vibrometers (LDVV) is proposed. It consists of quartz capillary (less than 1 mm of diameter), microlens at the end of capillary and fibers. Heterodyne and differential types of LDVV are released.
Original design of the multichannel two-reflector optical systems for astronomical and atmospheric devices have been considered. Their feature is the presence of odd or even number of holes in the secondary mirror corresponding to the number of the isolated channels. Formulas for determining diameter and arrangement of these holes are adduced. Proposed optical systems ensure considerably higher light transmittance (in 1.3 - 5.2 times according to isolated channels' number and screening coefficient value) than conventional two-mirror objectives. Technical realization of proposed three-channel objective was successfully produced.
Proc. SPIE 3055, Application of parallel operations for image reconstruction in computerized tomography, 0000 (28 February 1997); doi: 10.1117/12.267730
This paper deals with some problems in image reconstruction parallelism which arise when projections for divergent ray geometry and large image reconstruction matrices are considered. A suitable parallel architecture for image reconstruction is presented.