The linear and nonlinear optical properties of 0 - 3 nanocomposites are reviewed. These nanocomposites are prepared through wet chemical process in our laboratory and composed of host materials, such as: porous silica, polymer, liquid, containing ultrafine particles, such as: ferroelectrics and semiconductors. Our experimental measurements show that the linear optical properties of the nanocomposites can be modulated by the material preparation and the third order optical nonlinearity of the nanocomposites is largely enhanced. The future prospects for the preparation of the 0 - 3 nanocomposites and their applications to optoelectronic and nonlinear optical devices are discussed.

The optical phase conjugation is numerically shown to reduce the soliton interaction and the timing jitter of the soliton caused by the Gordon-Haus effect. With the conjugator, both the bit rate and the transmission distance of the soliton communication system can be improved. The criteria for applying the conjugation are discussed.

In the paper, 4-n-butoxy carboyl-methyl-urethane was synthesized by the reaction of 5,7- dodecadiyn-1, 12-diol-bis-chloro-formate with buthylaminoacetate hydrochloride. High conversion of monomer in solid state into polymer was obtained by (lambda) -irradiation. We fabricated high optical quality waveguiding film and measured the optical limiting effect of poly-4BCMU in chloride and nonlinear response time of poly-4BCMU.

The paper deals with the computation simulation of structural transitions in molecular films. The main attention is focused on the processes that occur under the influence of electromagnetic irradiation and result in producing the anisotropic orientational structures. The films with such properties can be used for information recording.

The bandwidth requirements for an adaptive optics system with R-C filter as servo response has been derived. The relationship of this bandwidth to Strehl Ratio has been presented in two cases of the constant wind speed and the constant pseudo-wind speed which predominates over the natural winds at all altitudes. It has been found that a bandwidth of hundreds hertz is more than enough for the former while thousands of hertz may be needed for the latter.

Sum-frequency generation with electromagnetically induced transparency is investigated experimentally as the generation of coherent Lyman-(Beta) radiation (103 nm) in atomic hydrogen. We demonstrate that with the application of a strong laser field to couple the 2 s and 3 p levels, the resonant Lyman-(Beta) transition becomes transparent, and the generated wave continues to grow without suffering resonant absorption. At a density-length product NL of 3 X 10¹⁵ cm^-2, a conversion efficiency of 2 X 10^-4 is obtained for the coherent 103 nm radiation.

The theoretical anaiysis leads us to an important conclusion. Using a specific sensor , the current for white sample can be divided into corresponding grey signals , which may be used as a spectrum standard. On the basis a new method of colorimetry is suggested.

Based on cascading of second-order nonlinearities we propose novel schemes for all-optical signal processing exploiting the tensorial nature of the susceptibility. Waves of the same frequency and orthogonal polarizations can interact via the generated second-harmonic, with an indirect energy transfer and the consequent possibility of gain and transistor action, polarization switching, amplitude and phase modulation.

The two-beam couple exponential gain coefficient depends extremely on the thickness of the crystal, the diameter of the pump light, and the temperature. The largest value may reach 237 cm^-1. The experimental results is reported and discussed in this paper.

Excitonic stimulated emission in the ZnSe-ZnS multiple quantum wells grown by the metal- organic chemical vapor deposition on GaAs substrates has been studied at room temperature. On the basis of the absorption spectrum and photoluminescence spectra under different excitation intensities measured, the major origin for the excitonic stimulated emissions in the ZnSe-ZnS/GaAs at room temperature obtained here are attributed to the exciton-exciton interaction.

The mutually pumped phase conjugate reflection induced by a self-pumped phase conjugate reflection of another mutually coherent beam has been demonstrated in a photorefractive Cu- doped KNSBN crystal. The dependence of the mutually pumped phase conjugate reflectivity on the intensity ratio of the two incident beams and on the incident position of the signal beam was measured. We obtain phase conjugate reflectivities of greater than 90% at 488 nm.

The picosecond optical bistability of Zn_1-xCd_xSe/ZnSe (x equals 0.23) multiple quantum well (MQW) has been observed by a Streak Camera at room temperature for the first time. In the absorption spectra of ZnCdSe/ZnSe MQW, there are two peaks at 515 nm and 530 nm. We discussed the origin of the two peaks and physical mechanism of the bistability.

Photoluminescence (PL) measurement of ZnCdSe-ZnSe strained layer superlattices structures subjected to an electric field has been performed. As well as the shifts of the PL energy, the main peak, due to the exciton emission was shifted to the lower energy side with increasing electric field. The reason is related to the field-induced electron-hole separation in the ZnCdSe well.

This paper has put forward the physical model of the flow-line structure of the light transmission in the film medium, established the non-relativistic quantum equation of the photo-flow-line, studied the mechanism of guiding light of both three-layer step-profile planar waveguide and three-layer graded-profile planar waveguide using the method of the quantum mechanics, introduced the concept of step-profile potential and that of step-profile quantum, explained anew the modulus of light propagation in the film medium, revealed that light transmission in the film medium abides by the movement law of the property of wave and particle, abandoned the concept of the classical electromagnetic wave and its theory system, tentatively formed the flow-line quantum theory of light transmission in the film medium.

In the paper, we report a theory of measuring the decay time of the dynamic grating and the dephasing time using time-delayed four-wave mixing with incoherent light for the larger ambipolar diffusion coefficient, and discuss the calculated results.

A new X-ray focusing system--the X-ray lens composed of guiding capillaries is introduced in this paper. The principles of this lens and its potential applications in different areas are discussed briefly. The preliminary results of developing this lens and using it in XRF and X- Ray Lithography in Beijing Normal University are reported.

In this paper, the design idea and application of an optoelectronic hybrid interconnection network are presented. In this network, the programmable electronic device is used for reconfiguring the topologies, and the optical fiber are used for transmitting the flows of data and instructions.

We report the demonstration of a very low drive voltage (V_(pi )) equals 1.7 V) LiNbO₃ electro-optic modulator suitable for 2.5 Gbit/s and 5 Gbit/s digital transmission applications. This modulator has the lowest reported voltage and length product of 3.5 V/cm and a 3 dB electrical bandwidth of DC to 2.5 GHz.

Different methods, including electrochemical etching, chemical staining, chemical staining plus electrochemical etching and immersion in boiling water have been used for fabricating or treating porous silicon samples. Comparative photoluminescence spectra of porous silicon samples. Comparative photoluminescence spectra of porous silicon fabricated by these techniques have been obtained. Porous silicon arrays have also been fabricated by electrochemical etching and chemical staining plus electrochemical etching on both high and low resistivity silicon wafers. Blue and green photoluminescence (at 440 nm, 460 nm and 540 nm peak wavelengths) on low resistivity silicon wafer was obtained from porous silicon made by electrochemical etching, chemical staining with UV laser illumination, and boiling treatment.

A design method of binary phase multi focus kinoform-type diffractive lens is presented. The optimization method presented in this paper is also valid for other binary phase diffractive optical elements. To demonstrate our method, a bi-focus diffractive lens with two phase levels has been fabricated and tested.

In this letter, we have studied the multiphoton Raman scattering properties of ZnSe-Zn_0.68Cd_0.32Se. At room temperature the Raman spectra with various lines of Ar⁺ laser excitation are investigated. We have observed up to the 5th order multiphonon Raman overtone for ZnSe-Zn_0.68Cd_0.32Se multiple quantum wells by the 476.5 nm line of Ar⁺ laser excitation. We ascribe this to the multiphonon outgoing resonant process.

In this paper, we report the photovoltage spectroscopy study of type-I and type-II GeSi/Si strained layer quantum wells at different temperatures ranging from 18 to 300 K. The experimental results show that for all the samples studied there is strong photovoltage at longwave bands in which the photon energy is less than the bandgap of Si. Four intrinsic exciton optical transitions and the saturation of exciton absorption have been observed. The mechanism for the photovoltaic effect in GeSi/Si quantum well structures is discussed.

Two types of fiber optic reflectively tapped delay line matched filters are produced for use as photonic packet address detectors in an optical ring network. Dielectric films evaporated on cleaved fiber ends function as light taps for the filters. Experimental results and theoretical calculation on photonic packet address detectors with 1 Gbps address code of (101) are reported.

The distributed amplifier gives a novel approach to a high speed photo-detecting amplifier combination. A 8.34 dB improvement in signal-to-noise ratio for a distributed amplifier is predicted at a bandwidth of 40 GHz over a conventional grounded-source amplifier combination.

A novel germanate acousto-optical glass has been developed. Its main characteristic parameters have been obtained. Comparison with reported properties of tellurite glass and heavy flint glass has been made. The acousto-optical quality factor for our germanate glass is better than that of heavy flint glass. An experimental method has been described briefly and the experimental results have been given.

A new type of polarization-independent single chip 6-gate integrated PLZT optical switch with single-mode fiber pigtails is reported. The switch consists of converging-and-compressing type of polarization-independent 1 X 1 PLZT optical switch as the elementary gates. The switch has a working voltage of 175 V, an extinction ratio of > 34 dB, an insertion loss of < 6 dB, and a 3 dB bandwidth of < 600 nm when operating at 1.3 - 1.5 micrometers waveband, as well as an on/off response time of sub-microsecond(s) .

Based on the band-filling effect, a novel intersectional waveguide semiconductor optical switch was fabricated and operated by carrier injection. Other than the conventional n-i-n structure and Zn-diffusion technology, a p-i-n structure was grown and O⁺ was implanted into the p-type layer to achieve restriction of injected carriers. This technology, which is published for the first time as we know, gets rid of the lateral expansion in the process of Zn-diffusion. It can be used to obtain narrow carrier injection region and perpendicular reflecting plane, and to exploit the injected carriers efficiently. At the working wavelength (lambda) equals 1.3 micrometers , the extinction ratio is as high as 15 dB with injected current 50 mA.

The all-solid lithiated electrochromic device for transmissive light control is described in this paper. This device comprises of a WO₃ film and a mLiF:nAlF₃ layer sandwiched by a pair of electrconductive layers. The transmittance of the device can be arbitrarily controlled within the range from 50% to 10%. The response time is 30 sec. for coloring and 40 sec. for bleaching, which is affected by the resistivity of ITO film and diffusion rate of Li⁺. The effects of substrate temperature and heat treatment on the properties of WO₃ films are discussed.

An electroluminescence model of bipolar resonant tunneling diode is carried out. The current is the sum of electron and hole current. The electron and hole density at resonant level of quantum well are related with the electron and hole current respectively. Radiative recombination rate formula is derived from matrix element, electrons and holes distribution. Result shows the large on-off ratio of light output can be achieved by the bipolar resonant tunneling diode.

An analytical model of (delta) -doped quantum well is developed. The results show that by using (delta) -doped quantum well structure, the area densities of the electrons and holes in the conduction and valence bands respectively can be increased by 4 orders of magnitudes compared with the n-i-p structure. Therefore the electroluminescence enhancement can be expected for the bipolar resonant tunneling diode of (delta) -doped quantum well.

The application of a voltage, V₀, across a photorefractive crystal in the presence of detuning is well known as a means of enhancing two-wave gain. By mounting a crystal of bismuth silicate, with faces cut parallel to the (001), (110) and (110) planes, in a rotating holder, measurements of two wave gain as a function of (theta) , the angle between the electric field vector E₀ (in the [001] direction) and the grating vector, K (in the (110) plane), have been made. Our results show that by having a non-zero value of (theta) the signal gain can be improved by a factor of two. Furthermore the experimental results showed that the (theta) dependent gain peaks differ in magnitude according to whether the crystal is rotated in an anti-clockwise or clockwise direction. In order to model the experimental results the steady-state expression for the space-charge field is extended to two dimensions and the usually neglected piezoelectric effect is included in the analysis of the modulation of the refractive index by the presence of this field inside the crystal. The asymmetry of the gain peaks is found to be caused by the optical activity of bismuth silicate and is predicted by the theory.

All-optical switching in C₆₀ has been studied using pump-and-probe method. The switching process is attributed to excited-state absorption of C₆₀ molecules. Simulated results of the switching behaviors are obtained from a five-level model, which agree well with the experimental data.

8 X 8, 0.88 micrometers LED matrix module has been successfully fabricated by hybrid integrating technique. The emitting power of a LED element is more than 200 (mu) W (I_F equals 20 mA). The emitting uniformity of all the elements is less than +/- 15%. In this paper, the design, structure, fabrication process of the module and its main properties are presented.

In this paper, a method of investigating a produce silicon-nitride microlenses with the thickness profile of spherical shape on flat quartz substrate by laser chemical vapor deposition (Laser CVD) was introduced. The results of tests indicated that the spherical microlenses with smooth surface were fabricated through regulating laser power, illumination time, concentration and mixture ratio of source gases.

This system basically works by a high frame-rate camera which obtains image signals through a high-speed solid state image sensor array and then memorizes digitally. By connecting the system with computers, various kinds of image processing and displaying can be implemented. In contrast to comparable CCD and CCPD devices, photodiode sensors require no surface electrodes, so there is no interference pattern or light loss and the full inherent sensitivity of a silicon photodiode is obtainable.

In this paper, the author conducted the research how to measure automatically the image point homogeneity of the high density matrix LED display, gave the measuring plan of the integrating sphere-photoelectric multiplex tube, manufactured the device which measured automatically the image point homogeneity of the matrix LED display. Because the device adopted MCS-51 microcomputer on chip for controlling system, quick and automatical measurement was realized. The device had the function that information was exchanged between user and computer so as to measure all kinds of high density matrix LED display. After correcting the measuring error, the precision of complete set of measurement equipment was up to 1.7%.

The windows of some opto-electronic detectors are made of polycrystals these days. For example, there are the well known Irtran series. There is also a mineral material called chalcedony was introduced into optics recently as a kind of scattering functional window material. But generally speaking, the mineral material is not uniform enough to be of practical usage. We now suggest some kinds of man made materials such as the Al₂O₃ ceramics and glass-ceramics which were generally used in the other areas except in optics. We have found that these materials have some special optical scattering properties.

A new structure electrooptic modulator is designed and constructed. It is suitable for deep modulation at high frequency and can be used to generate ultrawide sideband signals for forming ultrashort optical pulses. In experiments, phase modulation with a modulation index of 57 rad has been successfully obtained at 16.25 GHz, and thereby optical sidebands extending over as wide as 1.85 THz have been attained. The sidebands produced are broad enough to form subpicosecond pulses using the chirping-compression method.

It is generally difficult to perform interferometric measurements of surface shape or deformation outside optical benches because fringes are blurred by external perturbations such as mechanical vibration or air turbulence. For overcoming this we have developed active interferometers, in which fringes are stabilized by detecting their movement induced by the perturbations and feeding back the signal to a piezoelectric mirror of the interferometer. We also extend the system to an active phase-shifting speckle interferometer by which the correlation fringes are shifted under feedback control for automatic analysis. Examples of deformation measurement under air turbulence are presented.

There are many formulas to describe the input and output relationship of CRT. As the radiant output of CRT submits to the statistical distribution, the prediction of the colorimetry from these formulas is not good. Some deviation of the brightness are as high as 50%. There is a need to find a new method to calibrate CRT. We have set up an automatic measurement and calibration system with PHOTO 1980B, IEEE 4888 interface board, CRT and a computer.

This paper has summarized the achievements in the research on the digital image sampling and processing system for the automation of the fluorescent magnetic inspection for the axles of railway vehicles. The hardware of the system consists of 3 line array CCD-cameras, a multiplex A/D converter and an advanced microcomputer and its software has the functions of waveform display, real-time sampling and processing as well as automatic decision. A new method of intermittent driving with a long integration time and a high driving frequency is employed in the CCD-camera.

Noncontact measurement of mechanical vibrations is one of the actual problems in engineering. One of the methods widely used is spectrum analysis of Doppler shifts of coherent light reflected from a vibrating surface. Statistical properties of radiation scattered from an out-of-plane vibrating object have been studied. We are examining the possibility of deriving vibration parameters from statistical parameters of the dynamic speckle pattern formed by reflection of a coherent beam from the in-plane vibrating rough object.

A photomultiplier tube gain-suppression technique has been applied to a Thorn EMMI 9828B red sensitive photomultiplier. The gain-suppression mechanism and characteristics has been studied by measurement of the output changes of the photomultiplier during the application of the gain-suppression pulse while subjected to a constant incident light. Experimental results show that the 9828B photomultiplier tube can provide, at least, a two-step gain response for a constant incident light, when the gain-suppression pulse satisfies certain conditions. The application of the multiple-gain response of the PMT for the simultaneous measurement of photoluminescence of molecules of biological/biomedical importance is discussed.

The logistic map implicit in the Voigt profiles is revealed and the stability criterion of the Voigt profiles is found as (eta) < 1.04. The explanation of depressing the effect of spatial hole burning in gas lasers is given and other potential uses of the stability analysis of the Voigt profiles are mentioned.

A ultra-fast time-resolved optical multichannel analyzer (UFTR-OMA) is presented which can be used for capturing, processing and analyzing the multidimensional information of time, space and spectrum of ultra-fast optical phenomena. The UFTR-OMA is composed of three parts: input unit, streak tube unit and processing unit. We give the work parameters of the UFTR-OMA, measurement and processing results for ultra-fast optical signals.

In recent years, a considerable research effort has been expended on the field of optical current measurement in order to replace the conventional curient transformer (CT) used in power distribution 1 Although current measurement schemes based upon the use of an optical fibre as the sensing element were proposed as early as 1976, and a number of new methods which employ optical fibre, or bulk glass, or even electro-optic hybrid sensing elements have been explored and aviable commercial product has not yet emerged, despite the considerable level of research that has been devoted to the concept. An opticai current sensor consists of an optical current sensing element which measures the integral of the magnetic field along a closed (or nearly closed) optical loop around the current to be measured, an optical fibre link which connects the sensing element to an opto-eletronic control/processing unit, used to launch a light beam into the optical fibre and detect/demodulate the modulated optical signal collected from the fibre. According to the sensing mechanism employed and the sensing materials used, the optical current measurement devices may be categorized into three main groups: (i) optical current sensors (OCS) employing optical fibre as their sensing elements, (ii) the OCS type using bulk glass to sense the current, and (iii) the OCS type using electro-optic hybrid devices. In general, the principle ofthe operation ofthe first two types of sensors is based upon the so-called "Faraday magneto-optic effect", in which the polarization azimuth, 1F' a linearly polarized light beam propagating inside an optical material is rotated under the influence of a magnetic field, H, generated by the electrical current to be measured and is given by (Formula available in paper) (1) where V is the Verdet constant ofthe fibre core and 1 is the interaction length. Ifthe medium is subject to the magnetic field within a long solenoid this then becomes (Formula available in paper) (2) where N1 and NC the number of passes of the light through the solenoid and the number of turns of wire in the solenoid respectively, and I is the electric current. The electro-optic hybrid current sensors are often constructed from a conventional current Iransfonner interrogated with different electro-optic or fibre optic sensing schemes. Among these groups ofsensor, optical fibre current sensors have been discussed and reviewed by a number of scientists 1 3. Hence, in this paper, we will summarize the possible solutions for dealing with the stability problems associated with bendinduced linear birefringence in optical fibre current sensors and review the recent development in the area of current measurement using optic bulk glasses and electro-optic hybrid sensing techniques.

A Fabry-Perot etalon based on a Cu:KNSBN crystal with two surfaces essentially perpendicular to its c-axis has been, to the best of our knowledge, studied experimentally for the first time using the 632.8 nm radiation of a He-Ne laser as well as the 488 nm and 514.5 nm radiation of an argon ion laser. The reflectivity (when the refractive index grating has not started to build up) is due to the Fresnel reflection at the crystal-air interface. The transmittance and the finesse were found to be dependent on whether the c-axis is parallel or anti-parallel to the laser beam. The experimental data have been compared with the theory of He et al. The photorefractive gain parameter and magnitude of the refractive index grating were deducing and compared with those found by two-wave coupling experiment. The time dependence of the transmittance has been analyzed.

A new type of interference selective amplitude modulation spectrometer is described. The diffraction grating which is illuminated by collimated incident beam coming from a point aperture is placed in front of the incident arm of a Twyman interferometer. The flux is divided by the beam splitter into two beams and falling on two mirrors which are equivalent to two diffraction gratings. Then the interference fringe is modulated. The spectrometer has the ability to achieve high resolution and high transmission. Its mechanical stability is improved and can be used in the research of visible and ultraviolet region. Theoretical analysis of the flux and resolution is made. Using rectangle diaphragm the resolution is 1.35 times of the grating. At the last of the article the apodization technique with elliptical diaphragm is discussed.

A set of special driving circuits for CCDs to absorb the image pulse produced by laser pulse was successfully made. An optical system of short light distance with 30 power was set up to improve the resolution of the measurement of the displacement. So, the automatic measurement of thermal expansion is realized on the laser pulse thermophysical properties equipment, which is a main apparatus in the thermal physical properties research field.

Photothermal tomographic imaging is investigated in this paper. A new reconstruction model is proposed according to the thermal wave physics and our experiment setup. It was observed that the position and shape of the subsurface defects are more accurately reproduced in this method of reconstruction. Defects overlapped in depth direction is also resolved.

The paper reports the results obtained at the Institute of Atomic Physics, Department of Laser, in the field of absolute measurements of laser radiation. For the IR range of wavelengths an electrically calibrated detector was developed. For the visible laser radiation a Romanian made, predictable quantum efficiency silicon detector was used, which was compared with similar detectors provided by the National Institute of Standards and Technology, during an international intercomparison.

The measurement error caused by white-light spectrum in fringe scanning interferometry is a principle error. This paper presents the analysis of the error and results of computer simulation, which shows that the error is about 20% of measured phase and could not be ignored. Since the error is about linear, the compensation is simply to multiply a constant coefficient.

Self-reference single plate shearing interferometric technique used for collimation testing of light beams is described in this paper. Theoretical description of the technique and experiment results are presented in detail. Sensitivity analyses, practical applications and some further improvements on the precise measurement of the angle enclosed between the fringes are also demonstrated.

The temperature effect of laser Raman scattering spectrum of optical fiber was researched. We applied the optical time domain reflection technique of optical fiber, laser Raman scattering spectrometry, bi-wavelength two channel detection technique, high speed instantaneous state wave-shape sample average technique and computer technique to the distributed optical fiber sensor temperature system, use it for the measurement of temperature field in space.

The output intensity distribution from a white light interferometer (WLI) may be varied if the quality of the collimation lens used is poor or the alignment of the optical arrangement is not good. This effect will make the peak value of the central fringe be equal to or even less than that of the other fringes, and in consequence the WLI scheme will give an erroneous result for the determination of the central fringe position. This effect is analyzed theoretically using a computer simulation model, and the results from both the computer simulation and experiment are discussed and compared.

This paper reports a new installation to measure optical activity of materials. The characteristics of this installation are: a magneto-optic device has two kinds of functions, first, modulating the light signal; second, making the vibration plane of polarized light rotate. By this way, the volume of the installation is reduced, no rotation mechanism is used, and the sensitivity of measurement is raised. On the other hand, a half-wave retardation plate is inserted in the light. By this wave plate we can not only remedy the defect of small linear range of magneto-optic element, but also can reduce the error of measurement by enlarging the angle of deflection, when we measure the little angle. Using program control DC supply as the linear scanning voltage, we can link the installation with computer and make the measurement automatic and fast.

Proposed here is a convenient optical system to collimate the crescent shape blue laser beam radiated from a Cerenkov SHG in channel waveguide configuration. This collimation system makes use of the reflection of a parabolic mirror and has a very large tolerance to the mirror displacement. The anisotropy of the nonlinear crystal on which the waveguide is fabricated has been taken into account. The optimum mirror location to obtain a collimated blue laser beam is given in accordance with Marechal's Criterion. By using an object lens, the collimated beam can be focused down with the spot size less than 1 micrometers .

In the paper, it is realized that the optical homogeneity of optical glass is tested layer by layer according to the interference principle of the dual surface of the matched liquid, and assisted with computer handling. The characteristic of the method is that the horizontal plane used as standard dual planes reflecting light for producing interference patterns of equal thickness, and thus it may be used for testing the optical homogeneity of optical glass when it is disappeared in the matched liquid. The result that the optical homogeneity of optical glass tested may be realized with computer. Such results have given interference pattern of optical homogeneity of any layer, in the optical glass, the biggest inhomogeneity value in this layer and the change figure on the value of any layer. The magnitude degree of testing precision is better than 10^-4.

This paper analyzed the signal conditioning received by the Underwater Object Laser Detection system and designed a kind of Photomultiplier Gain Control system to compress the signal's dynamic range. Finally, some experimental results are presented and analyzed.

An improved method involving three phase conjugates for measuring the phase of complex third-order nonlinear susceptibility ((Chi) ⁽³)) directly has been developed. The principle of this interferometric method is that the phase shift observed on an oscilloscope between two interference signals equals the difference of (Chi) ⁽³)'s phases of two nonlinear media. Therefore, if one of the two media serves as a standard with its known phase of (Chi) ⁽³), the other one's phase can be determined directly. The (Chi) ⁽³)'s phases for some saturable absorption dye-doped polymeric films such as Eosin Y doped in polyvinyl alcohol (Eo/PVA) has been measured at different wavelengths by using this interferometric technique.

This paper describes briefly importance of endpoint detection of the plasma etching and reactive-ion etching for LSI and VLSI circuits. The monitoring principle, design ideal and construction of the instrument for endpoint monitoring are described in the paper and monitoring results on line have been given. Finally the paper will discuss the load effect of the plasma etching and laser lateral interference influenced on monitor precision.

In this paper, a new way for eliminating the emissivity uncertainty by constructing a cavity on the measured surface to get a grey surface is proposed, and the affection to its realization as parameters changing in some extend is also discussed.

High-reliability, high-performance microwave electro-optic (EO) modulators, low crosstalk EO switches, polarization-insensitive fiber optic isolators, tunable filters, variable attenuators, couplers, endless polarization controllers, and optical amplifier modules for aerospace, terrestrial and undersea applications are presented in this paper. Component structures, performance results, and reliability data will also be discussed.

CdS-CdS_1-xSe_x SLSs were grown on (111) GaAs substrates by MOCVD, and their characteristics were analyzed by PL measurements. Luminescence results show that the band-gap of superlattice can be controlled by changing compositions, and crystalline quality of SLSs can be improved by controlling composition and inducing buffer layer. This indicates that the PL spectrum is more sensitive to investigate the structure of SLSs.

The analysis of optical antenna gain for laser communications has been made by some authors in the past years, most of them pay attention to on-axis situation, however, in latter years, laser navigation becomes interested, off-axis situation has been given more considerations, four-quadrant detector is commonly used for TEM₀₀ mode detection. But it is unsatisfactory in the case of the divergent angle exceeding some criterion for large variations of distance detection, especially, it is difficult to make a precise judgement for what is the distortions of the wave front by random disturbance. This paper suggested a method of multi- ring detection to meet such demand.

In this paper, an on-line high speed measurement method for section shape of the banded workpiece moving at high speed, such as the hot rolled section steel, is proposed and realized. Some important technologies in the system designing are described.

The results of experimental study of probability density function in case when a number of scatterers in the resolution element of optical system is small are presented. The measurements have been carried out with ground glass and roughly polished plexiglass specimens at (lambda) equals 0.63 micrometers . Experimentally derived histograms of probability density function were in good agreement with K-distribution model.

The paper discusses some optical methods of measuring the profile of disk non-contacting. Grazing incident interferometer, Color schieren, and Moire deflectometer. Especially in the paper a new measuring method and instrument is introduced which is a pointwise instrument with an optical probe. It can measure a global and local profile of a disk in tangential and radial direction at the same time, without sacrificing the measurement accuracy. The resolution of the probe is 0.3 nm, the instrument accuracy better than 0.04 micrometers , the dynamic range larger than 5 mm.

A computer simulation of an in-fiber interferometric hydraulic pressure sensor is carried out by use of a finite element method. Both the interference between the same modes from the two arms of the interferometer and the beat length of the two orthogonal modes in the polarization- maintaining fiber which is used as the working arm of the interferometric hydraulic pressure sensor are examined, for various types of polarization-maintaining fibers under different values of hydraulic pressure. As a result, the design of the in-fiber interferometric hydraulic pressure sensors may be optimized.

This paper presents the influence of background radiation on the properties of SPRITE detectors, thermoelectrically cooled at 200 K and operated within the spectral range of 3 - 5 micrometers for detectors with the field of view ranging from 0 to 90 degree(s) and background temperature 300 K.

The shearing interferometry of phase shifting with double frequency grating and semiconductor laser is proposed. By using this technique, the experimental results of the temperature field of a heating plate are obtained and compared with those tested by a thermoelectric couple.

We review tunnel ionization of atoms and molecules by an intense CO₂ laser. Newest recent results and calculation are also presented concerning dissociative tunnel ionization of diatomic molecules.

It has been observed that Er³⁺-doped fiber lasers, under certain conditions, can be self-mode-locked and self-Q-switched simultaneously without any additional intracavity components. An experimental investigation into such phenomena has been conducted with various fiber lasers. A self-mode-locked pulse width shorter than 500 ps (the limit of our measurement capability) has been obtained within the self-Q-switched pulse at 8 kHz repetition rate and with 500 mW peak power. The fiber design and laser performance are presented. The mechanism of operation and the potential applications are discussed.

This paper describes state-of-the-art aluminum-free 980-nm laser diodes which are intended for pumping erbium doped optical fiber amplifiers (EDFA's). There are three principal issues for these laser diodes to be considered for the EDFA applications: light output power, efficiency of coupling the power into a fiber, and reliability. It has been shown that the lasers can launch 400 mW in single transverse mode of operation into free space. A coupling efficiency of 53% and a fiber-coupled power of 58 mW have been demonstrated. Because the Al-free 980-nm lasers are new, their lifetimes have not yet been thoroughly studied. However, some tentative experiments indicate that extrapolated lifetimes may be several hundred thousand hours at reasonable power levels. Thermal roll-over tests prove that the lasers withstand high currents and temperatures without any sign of degradation.

In this paper, we summarize the current technological development and prospect of RF transversely excited diffusively cooled CO₂ lasers, point out that the high beam quality, compact device size and high performance are the future development trend of high power CO₂ lasers, and propose a volume scaling technique for obtaining high beam quality and compact high power CO₂ lasers.

Based on analysis of the effects of carrier leakage, non-radiative Auger electron process, intervalence-based absorption as well as lattice mismatch on lasing characteristics in InGaAsP- InP lasers, we have optimally designed and perfectly grown by a modified LPE technique the large optical cavity structure in order to obtain the 1.3 micrometers and 1.55 micrometers InGaAsP- InP lasers with low threshold current density, high output power and high characteristic temperature.

Three new compound structures of the optical fiber resonators for generating the single longitudinal mode are reported. Their characteristics are investigated.

Frequency conversion in Multiple Quantum Well travelling wave amplifiers, when a strong pump is injected in the device and under highly saturated regime, can show longitudinal power fluctuations up to hundreds gigahertz beat frequencies. A model which explains such phenomena is presented.

The operation characteristics of a dye laser device designed for converting a fixed wavelength pump pulse emitted from a nanosecond non-mode lockable laser such as nitrogen, excimer laser into high-power picosecond laser pulses spectrally adjustable between 386 to 700 nm are presented. This device is made very compact, simple to operate, it produces a pulse-shortening factor greater than 100 (from 6 ns down to 50 - 80 ps) with a single stage. The spectral and time processes involved in this pulse shortening method are exposed with 2D-streak camera analysis and are discussed with a rate equation model.

Polarization insensitive laser stabilizer which can be used for both polarized and unpolarized beams is presented. The system utilizes a polarization independent variable attenuator which is composed of two identical polarization beamsplitting prisms and an improved Pockels cell to control the incoming laser beam intensity. It is characterized by high stability, high transmission and lower control voltage.

In this paper, we present experimental results of GaAs/GaAlAs laser arrays with linearly varied stripe widths. Near-diffraction-limited, single-lobed far field pattern and single longitudinal mode emission spectra are obtained. Experimental results are compared between uniform and nonuniform stripe widths. Furthermore, the spectral properties are discussed qualitatively.

We have shown that, other than some minor differences, a moving-mirror mode-locked laser is identical to a frequency-shifted feedback cavity laser. These lasers have been studied using the Maxwell-Bloch equations under the thin-sheet-gain approximation. The Maxwell-Bloch equations were solved numerically by the Runge-Kutta method.

This paper reports experimental results of LDA-pumped, intracavity frequency-doubled Nd:BGO laser.

Problems concerning design and test of a portable goniometer are discussed. A ring laser scanner is selected and tested for the goniometer. A rotating table has been fabricated. As shown by the test results, accuracy of the goniometer is better than 2 arcsec.

A large capacitive coupling discharge main pumping system and a high frequency excited transverse CO₂ laser have been studied. By means of special high dielectric constant ceramic covered electrodes as main electrodes and preionization electrodes, the discharge characteristics and output characteristics of CO₂ laser are presented. In our pumping system, the high input power density, stable discharge and output power density, stable discharge and output power have been achieved. In the compound dielectric electrodes with preionization pumping system, the discharge is more homogeneous and stable.

This paper gives the analytic expression for non-steady amplification in crystal fiber by means of travelling-wave theory and the relationship between signal light and pump light. The experiment has proved this theoretical result.

The use of the fundamental and frequency doubled outputs of a Q-switched Nd:YAG laser as a rapid non-contact method for removing hydrocarbon pollutant layers from sandstone is reported. Color measurements of unpolluted stone were made using a Minolta Chroma meter to provide target values for the laser treatment. Color measurements and examination using a microscope of the polluted stone after laser treatment showed that 1064 nm laser pulses were most efficient at removing the polluted layer and at retaining the original color of the stone. The optimum laser pulse energy was found to be 6.8 mJ, above which damage to the stone surface occurred, resulting in a bleaching of the stone.

Increasing collision frequency may decrease transition probability which return to low energy state from high energy state. It is advantageous to forming metastable, decreasing collision frequency may increase transition probability which return to low energy state from metastable state. The collision frequency may be changed by transform the pressure P or number sensity n. As the P or the n very low and inverted population, may form forbidden line laser.

Numerical models have been developed to optimize a Pr³⁺-doped fluoride fiber upconversion laser pumped by an Yb³⁺-doped silica fiber laser. Numerical and experimental results of optimizing the wavelengths in the system are presented. It is found that the optimum lasing and pump wavelengths of the Yb fiber laser are largely determined by the peak ground state absorption cross section and power ratio respectively. The optimum power ratio is different for different praseodymium lasing wavelengths.

The factors which affect the output power of the 1.3 - 1.55 micrometers lasers are considered in this paper. The separate confinement structure (SCH) is chosen to prepare the 1.3 micrometers SCH semiconductor lasers with high output power and low threshold current. Their pulsed output power is more than 3 w and threshold current density is less than 2.5 KA/cm².

A He-Ne laser beam is coupled into 50/125 micrometers monofil optical fiber with the aid of the free lens coupler, after that it entered into the laser pin through the fiber-optic connector. The attenuate coefficient of the lens coupler is adjusted continuously, from 0.5 dB to (infinity) . The laser pin is composed of inside pipe and outside pipe that they are all stainless steel pipe. The inside pipe pierce into the outside pipe. In the inside pipe there is a large core fiber, they are stuck to together to each other. In order to observe back blood, there is a hole of 0.3 mm in diameter on the flank of the outside pipe. When the laser pin stab into a vein, the blood is irradiated directly by the He-Ne laser beam. The laser pin can be used only once, for the price of the fiber-optic connector is lower.

A transfer matrix analysis based on the Green's function method is used to derive the expression for the spectrum of a three-section phase-controlled DFB laser. This is of particular interest for implementating a continuously tunable optical filter. The influence of various parameters, such as phase shift and reflectivity, on the spectral behavior are studied theoretically. Analysis shows that a three-section DFB laser presents a single-mode spectrum over a wide continuous tuning range of around 2 nm. This result is very interesting for coherent and WDM systems.

Travelling-wave rate equations have been used for studying travelling-wave semiconductor laser amplifiers (TWAs). Theoretical research predicts that TWA has been available for 10 Gbit/s order fiber optic communication systems. Experimental results prove that TWA has been applied for 700 Mbit/s fiber optic communications systems.

The gain characteristics of an erbium-doped fiber amplifier were investigated as a function of pumping wavelength with a Ti:sapphire tunable laser in range from 950 nm to 1000 nm. A maximum gain of 49.6 dB at 979 nm pumped wavelength and a bandwidth of 10 nm at 3 dB gain compression were obtained.

We present the characterization of a bidirectional optical transmission with two semiconductor lasers amplifiers which work alternately as a modulator or a photodetector. Error free transmission is achieved up to 1.555 Gb/s.

A laser-diode-pumped Nd:YLF laser passively Q-switched with a YAG color center chip is developed. When cw pumped with a laser diode array, the Nd:YLF laser produces pulses of 25 ns duration at 1.047 micrometers , with an energy of 8.7 (mu) J and repetition rate of 0.7 kHz approximately 5 kHz. Data are presented on pulse width, energy, and repetition rate as a function of laser cavity length and the pump power.

A new dispersion compensation method for high-speed wavelength-division-multiplexing terrestrial systems with cascaded EDFAs was proposed. Specially designed dispersion-shifted fiber (SDDSF), generating -2 approximately -4 ps/km/nm dispersion around 1.55 micrometers is used to avoid severe four-wave mixing, while CCITT G.652 non-dispersion shifted fiber is used to compensate for the negative dispersion of SDDSF over the entire EDFA bandwidth. The eye opening penalty of dispersion in systems of bitrate as high as 10 Gb/s per channel after 1000 km fiber transmission could still be less than 1 dB. It is a cheaper, more simple and reliable scheme.

This work is devoted to the investigations of the diffractive optical elements (DOE) fabrication with the help of optical methods and registering media on the base of chalcogenide vitreous semiconductors (ChVS). Most of attention is devoted to the processes of holographic diffraction gratings fabrication, but also are investigated formation processes of other types of optical elements. The results of the investigations on fabrication processes of DOE's with blazed profiles are discussed, method of DOE's direct recording with the help of sharpfocused laser beam is considered most perspective. Processes of obtaining the DOE's polymer copies from the initial ChVS matrices are considered. This can be done directly using the photopolymers, or by obtaining the phase-relief metallic matrixes with the following casting, embossing.

For InGaSb/GaSb strained-layer structure, the effects of elastic strain are induced by lattice mismatch on the effective masses and band offsets at (Gamma) -point. We found that the effective masses (electron, light- and heavy-hole) become anisotropic, and the band offsets are also effected in a strained layer. The E-k relations were calculated using the method of linear combination of atomic orbitals. Such a structure is, at the same time, of type I for heavy-hole and type II for light-hole. Mini-subbands in InGaSb/GaSb strained-layer superlattice have been calculated using the modified Kronig-Penney model. This strained structure can be applied as two-mode transition photoelectronic devices.

Infrared sensors can profitably be employed in environmental monitoring because of sensitivity, specifity and stability of the interaction between infrared radiation and molecules. Recent progress in infrared sources, spectral filters and detectors allows the construction of small, energy-saving, reliable and almost maintenance-free devices. Almost monolithic integrated optical devices in development.

The authors see an analogy between a molecular beam and light beam13. In the case of optical modelling of an effusion molecular beam, in a simulation system the light from the source was introduced via a diffusion ground glass plate into the "effusion" channel. The inside of the chanel was lined with the corrugated aluminium foil of a high reflection coefficient and the light was reflected from the wall in chaotic directions, just like molecules from the wall of the actual channel (Fig. 7). The intensity of the light beam distribution was measured with a photodetector. This means that information about high vacuum processes can be received from investigations performed under normal pressure.

We report here the temporal characteristics of gain-switched Ti:doped sapphire lasers pumped by different pumping scheme. The variation of temporal characteristics of output pulses and output energy versus wavelength were studied. The optimal conditions of generating stable ultrashort pulses are also given.

This paper proposes use of the simulated evolution (SE) method for design of matched filters which possess a recursive digital form and match with the bell-shaped pulse signal of infrared (IR) detectors for signal pre-processing in IR search systems. The SE method can be used to search for optimal filter parameters. Simulation results are presented to show the advantages of this new design methodology and the potential of its applications to design of non-standard shape filters.

The measured results by the radiometers with PbS and InSb detector for the reentry bodies are described in this paper. The standoff ranges of the radiometers reached 100 km and 60 km, some features about the targets are given.

In this paper, on the basis of the analysis of the main noise sources of the `Low Light Level (LLL) CCD Camera' which our teaching and research section developed, a new method, mode filter, is put forward and taken to suppress the LLL image noise. At last the detailed analysis and discussion on the processing results are given.

In this paper, on the basis of temperature-moisture coupling theory, a system of energy and moisture equations are determined and solved for average surface temperature and moisture. Simulated vs measured radiometric diurnal average surface temperature of the soil correspond within 2 degree(s)C, which show that the theoretical model is able to simulate exactly the variation of the soil surface temperature and moisture with the type of the soil material and the environmental conditions.

Photon counting MCP image intensifier (PCIT) of both converting and proximity focusing type have been designed for adaptive optics applications. The principal performances considered in this paper are as follows: quantum detection efficiency, brightness gain and photon ratin, maximum output brightness, dark counting rate, and pulse height distribution. In the design of the PCIT, five schemes have been analyzed and compared to each other. The design results of parameters mentioned above are also given.

The response time of photoemissive materials is required for detecting ultrashort duration laser pulses. The photoelectron's response time will increase with increasing energy of photons. If the surface potential barrier of thin film declines, the photoemissive sensitivity or quantum yield will rise, however the response time will also increase which means that response time characteristic gets worse. As an example, the response time for Ag-O-Ca thin film is calculated.

This paper introduces a new structure X-ray cathode consisting of new structure haloid coating integrated on the input surface of MCP that is applied in single proximity x-ray intensifier. The current response characteristics of different structure CsI, CsBr and KBr cathodes are compared. The conclusion of excellent output response of the dense-loose-dense three-layer new structure CsI Cathode in the energy range 40 - 50 Kev is obtained.

Broadband optical communications systems require the technology of high-capacity, high- information-bandwidth optical fiber transmission. While one can push TDM to higher and higher speeds (e.g., 40 Gb/s) to increase the information transmission capacity in an optical fiber system, a well-known alternative approach is to use the technique of multi-wavelength multiple-optical-channel transmission, or, wavelength-division-multiplexing (WDM). This talk will briefly review recent advances reported in the published literature on WDM and discuss potential optical fiber system and network applications of WDM technologies in optical communications.

Optical fiber systems have been developed during the past twenty-five years for primary applications in the high speed digital communication of information. Using much of the same rapidly-developing technology optical fiber sensor systems have been developed during the past fifteen years for the measurement of a wide range of physical observables and applications in aerospace and hydrospace, civil structures and biomedical instrumentation systems. The major advantage of optical fiber sensor methods over conventional sensor systems is the all-dielectric nature of the fiber and the intrinsic avoidance of electromagnetic interference and ground loops that plague wire and metal-based sensing networks. For physical property measurements in smart materials where actuator elements and arrays are driven by high voltage electrical signals, such immunity is especially important. Another major advantage is the operation of fiber sensors above the temperatures at which most conventional sensor instrumentation will not operate. Such operation allows the use of properly designed fiber sensors in situ for the analysis of the fabrication conditions of smart materials, as well as their performance in high temperature environments. Sensor elements incorporated into the material during fabrication may in some cases be used for material evaluation post processing. This paper briefly suggests the use of such optical fiber sensor elements during the fabrication, inservice lifetimes and damage and degradation phases of smart material and structural systems.