A new approach to modal index determination for planar waveguides is presented, which is an extension of the Ruschin-Lit mode counting rule. Unified half phase shift relations related to the above rule are improved and completed. The approach applied to some special waveguides and numerical results are given.

A novel formula for dispersion properties of MQW waveguides with arbitrary refractive index profile, which is based on the transfer matrix technique in the equivalent index approximation, has been developed. It is shown that the numerical accuracy of the formula is indepedent on the period numbers of the quantum well.

The numerical calculating method of refractive index profile in optical waveguides is discussed. By using this method, the two dimensional distribution or line distribution along x, y direction of refractive-index difference can be obtained based on the output pattern of optical waveguides. The measured result of the index difference profile of a Ti:LiNbO3 waveguide in the direction perpendicular to the substrate surface is given.

Conjugate image of the Talbot image is observed in the experiments. The principle and method of the experiments for observing the conjugate image of Talbot images are discussed. The experimental results and brief theoretical explanation are gived. The author presented for the first time that the m value in the formula of Talbot self-imaging may expand to the nagative.

The formula and criterion of the Strehl intensity ratio consisting of the aberration and roughness are developed. According to the roughness wavegront Strehl intensity ratio criterion, the gradation of image quality is classified into three grades:"non-ideal", "good" and "very good". The roughness tolerance of λ/20 ～ λ/80 is estaflished.

In this paper, the iterative algorithm for the inverse problem solution of optical CT. Using the forward model is studied in detail, with special emphasis on the FEM solution for Jacobian of the forward operator. The regularization method that has been widely used in image restoration is adopted for solving ill-conditionness of the inverse problem. Finally, the complete strategy for the FEM solution to the optical tomography is given as a conclusion.

A feed forward neural network is applied to the analysis of K-shell X-ray line spectra from a laser produced plasma, and to the accurate determination of the plasma parameters. After training on error backpropagation algorithm, the network can effectively produce the electron temperatures and the electron densities. The use of this method for X-ray is illustrated. Spectroscopy of a high density and high temperature Mg plasma is illustrated. The both parameters are produced, and agree well with the results from conventional method.

A novel all-azimuth shearing interferometer has beam developed to evaluate and measure collimation, divergence and other parameters of laser beams and the amount of defocusing in systems of collimator and beam expander. It also can be used to test wave front aberrations and to adjust optical systems. In this paper, the basic principles of all-azimuth shearing, characterization of the tester and its applications are described.

An optical fiber probing system has been designed and manufactured with special consideration for simultaneous measurement of Raman signal and scanning tunneling microscopy (STM) image. In order to improve the collection efficiency of Raman signal, the optical fiber probe carrying one excitation fiber and five collection fibers are surrounded the STM tip to fully make use of the limited space. Moreover, the graded refractive index (GRIN) lens with very short focal length has been used to ensure larger relative aperture. With the aid of this probing system, Raman spectra with good signal-to-noise (S/N) ratio have been obtained, and a combined base of Raman spectroscopy and STM was constructed. The preliminary results have shown that the combined base provides a new method for in-situ and real time studies on solid/gas and solid/liquid interfaces, by which the topography of the solid surfaces and the detailed structural information of adsorbed species can be obtained simultaneously.

The design, construction and imaging experiments of a soft X-ray normalincidence multilayer imaging Schwarzschild microscopical system with 10. 5 ×magnification at 18. 2 nm are presented. The resolution limited by abberration and diffractions less than 0. 2 μm. Multilayer Mo/Si coatings were deposited simultaneously onto both mirrors of Schwarzschild objective. The period of multilayer and number of layers are 9. 5 nm and 41, respectively. The images of 20 pl/mm and 55 pl/mm mesh were taken with laser produced with this imaging microscopic system.

A terawatt femtosecond Ti: Sapphire amplifier system is demonstrated. The self-mode locked Ti:sapphire laser pulse is amplified by the chirped-pulse amplifier to the energy as high as 84 mJ per pulse. The pulse duration is 75 fs and the peak power exceeds 1 TW.

The coherent submillimeter wave generated from the GaAs surface exited by ultrashort optical pulses is incident- angle dependent and the ratio of forward and backward radiaion is related with the optical incident angle. The relationship between the thichness of the metal film coated on GaAs surface and the amplitute of submillimeter wave are measured. The theoretical model of the photon carrier dipole gives a well explanation on the angle dependent relatonship and the polarization of the coherent submillimeter wave.

The behavior of the power spectrum of diode-laser pumped Nd:YVO4 laser has been studied by using a delayed self-heterodyne interferometric technique. The linwidth is 25 kHz in 1 sec. sweep time. The relationship between the linewidth and the cavity length was measured.

In this paper, We study the atom-field coupled behavior for degenerate Raman process in the presence of the stark shift, the influence of the Stark shift parameter on the atom inversion and the field entropy are discussed.

Based on the pertubation theory of quantum mechanics, the formula of ionizing cross-section of the four- photon ionization processes with either two- photon resonance three-photon near- resonance or three- photon resonance two- photon nearresonane is derived under the condition of coherent exciting ionization. The result implies that the ion intensities of the two processes above relate to the molecular population on the initial energy levels that the processes concern. The four-photon ionization spectra are experimentally measured and analyzed with this result, which shows that the ionization process is one with three-photon resonance.

It is discovered that driven by the super strong laser field, the oscillation of electrons, due to their relativistic motion, will generate harmonic emission. The characteristics of the harmonies are analyzed with a single electron model in the case of different laser field polarization. It is found that the harmonic emission is more effective in the case of circular polarization than linear polarization.

High and stable values of phase conjugation (PC) fidelity are available by use of a two-cell stimulated-Brillouin-scattering (SBS) PC mirror. Making SBS return to YAG Q-Switched oscillator and output coupled with polarizer, the SBS output pulses take an advantages of short, tunable and stable good quality. The principle of compressing pulses and the influence of PC mirror's relative positions on SBS pulse width are analysed. A SBS pulse with 2.5 ns width and 9 mJ energy is obtained.

Phase conjugation (PC) and optical storage in a liquid-crystul polymer film were studied by degenerated four-wave mixing. On the basis of resonant absorption,high-efficiency phase conjugated beam was obtained while low-intensity incident waves were used. When intensities of the waves increased to the order of 10 W/cm2, the film showed a behavior of optical storage and high- order diffraction was observed. As intensities of the incident waves reached the order of los W/cm2, three groups of backward and forward high-order diffraction beams were detected. The highest-order diffraction beam was the 3rd-order one. After turning off two of the incident waves, the high-order diffraction produced by the remained wave didn't decrease obviously. After the bleaching, a brilliant hologram spot was observed on the film and could be maintained over 120 days under general storage conditions.

The anglar dependence of self-diffraction efficiency of laser-induced thermal gratings is discussed. Experimental results show that the efficiency is inversely proportiona1 to the fourth power of the angle. The theoretical analysis explains the experimental results.

Using the Spectra Physics Company produced 1. 1 W, 90 fs regenerated mode locked Ti:Sapphire laser as pump source, KTP as nonlinear gain medium, and BBO as a intracavity frequency doubling crystal, we construct a synchronously pumped intracavity frequency doubled fs KTP optical parametric oscillator (OPO). It's output tuning range is from 528 nm to 586 nm, the optimal average output power is 240 mW, and the pulse width is about 100 fs. The oscillation of this OPO system can last for about three hour, even without a feedback system.

The bird-Wings phase conjugator (BWPC) using Cu: KNSBN is demonstrated and some experimental phenomena and laws are given in this paper.

A new method for determining the field-cross correlation has been proposed and demonstrated theoretically and experimentally. It can be used to the measurement of pico-and subpico-second ultra fast optical processes.

A magneto- optical bistable device of whole glass fiber structure based on magnetostriction is developed. In comparison with a separate-element magneto-optical bistable system, the bistable switch power of this system has reduced by 2-3 orders. The results are in good agreement with the theoretical calculation.

The paper analyse non-adiabatic modification of energy transition and dynamic evolution for two-level atom in cavity with quantum high order adiabatic approximation (HOAA). The approximative condition for atom capture is described quantitatively.

We prove that, for any stable propagating monochromatic scalar beam in vacuum, the radial component E and the z component E of the beam cross-section energy are invariances and independent of the position of the cross- section if the evanescent waves of the plane-wave spectrum of the beam are ignored. The expressions of x and y component of beam energy diffraction divergence are derived.

The transverse- effect of a light field in a nonlinear- cavity is studied by numerical simulation. The nonlinearity behaved the phase variation being related to light intensity as it passing through an amplification medium. The results shows that when the nonlinear coefficient is changed, the ditribution of light field in the cavity exhibits various spatiotemporal instabilities, such as the transitions of transverse modes, periodical spatiotemporal phenomena and optical vortices.

A new kind of fiber grating - active fiber gratings is proposed to avoide the energy loss in optical pulse switching process of nonlinear fiber gratings. This paper studies the characteristics of switching dynamics in erbium-doped nonlinear fiber gratings under cw light. The results show that under cw light, the switching of the proposed fiber grating is a phase-transition-like process. As a cw light switching device, the active fiber grating is not as good as expected, but it is advatageous as a pulses generator.

In this paper, optical microscopy (OM), scanning electron microscopy (SEM)and scanning tunneling microscopy (STM) are used to investigate the microstructure of recorded organic thin film. Bubbles are found for organic thin film after laser irradiation. Among these methods, STM can provide more detailed and accurate three dimensional parameters of the microstructure. The microstructural study plays an important role in analyzing disc performance and recording mechanism.

The fomula of insertion loss and isolation of polar izati on - indePendent walk - off optical isolator are presented theoretically by Jones Matrix in this paper. The influcences of polarization beam-splitter , Faraday rotator and half-wave plate on insertion loss and isolation are discussed. The experiments of the optica1 isolator developed by the authors show that the fiber to fiber insertion loss was 1. 46 dB and isolation was 34 dB and with size of 13 ×10 ×46 mm3.

The cross-section of laser collective scattering in a fully ionized plasma is equal to the Thomson scattering cross-section multiplying a form factor. The form factor is determined by the density fluctuations of electrons. On the basis of the considering electromagnetic interactions between charged particles, an analytic expression of form factor spectrum of laser scattering in a relativistic magnetized plasma is derived.

The interface potential of WO3 film and lMLiClO4- PC solution and its measurement are discussed. Three kinds of WO3 films with different electrochromism proPerties were made, and their variation of the interface potentials were measured as a function of the number of Li + ions injected into WO3 film. It is found that the limited maximum number of injected Li+ ions is predicable through the variation trendaney of interface potential. The best deposition parameters of thermal evaporation for electrochromic WO3 film are obtained.

We have obtained the population of the highly excited Rydberg states of sodium atom by two-step excitation using tunable lasers. The field- ionization thresholds for excitation states were measured by using a pulse electric field, which applied to interaction region after the laser excitation. Lifetimes for ns (n=20～24) and nd (n=19～23) states were measured by delaying field-ionization, and compared with the calculation values. The influence of some factors on lifetime is discussed.

The Franz-Keldysh shift of the wavelength of peak response of (HgCd) Te detectors has been investigated experimentally. Our experimental measurements show that the Franz-Keldysh effect does have significant strength in (HgCd)Te and may lead to a considerable shift of the optical absorption edge toward the longer wavelength in a strong electric field.

Bragg grating was photoimprinted on the core of hydrogen loaded commercialized communication fibers using 193 nm ArF excimer laser and silica phase mask. The obtained fiber grating has a reflectivity greater than 90%, and a FWHM bandwidth less than 0.6 nm.

The time- resolved luminescence spectra of laser induced plasma from BaTiO3 were studied with a optical multichannel analyzer (OMA Ⅲ). The time-of-flight spectra of various particles, by which the concentration distribution of the responded particles was represented, were built by the emissive intensity of the same particles at different time. The spatial length of the ejected pulsed particle beam (i. e. plasma) was evaluated by the time-of-flight spectra, and the dependance of its dimension on the partial pressure range of buffer gas for laser deposition of oxides films with multielement was suggested, and the necessity of about 30 Pa oxygen partial pressure during laser deposition of high Tc superconducting films is explained.

The fluorescence charecteristic parameters of Tm3+ ions in Tm: YAG crystals for radiative transition probabilities Aij, non-radiative probabilities Wij, cross relaxation probability P, fluorescence lifetimes τ and fluorescence branching rations βij, et al. are caculated. The dependence of the population of 3F4 level on dopant concentration x is studied. The optimum relative concentration xop of Tm3+ ions of 4. 9～ 6. 4 % is obtained,when the range of probablility of excited level by pump light are 102～ 106 sec-1.

The spectra of terminal products from five general high explosives are studied by using detonation spectrum technique developed by the authors. The results show that H2O increases with negative oxygen balance increasing. The CO2 increases with the increasing of carbon content in the explosive, and C2 raises too. It provides some useful data for selection donor explosive used to synthesize diamond by detonation product method. Comparing the measured data with ealculating values from BKW equation, the results are similar. It shows that the monochrometer technique is an effective, economic and convenient method for study microscopic mechanism of explosive fast reaction.

In this paper, further disscussion about the FAT -a new spectral estimating method proposed by the authors, is offered and a method to correct the relative intensity is presented. An algorithm of quality factor is also proposed to judge the spectral line shape optimization and the estimated spectra.

Low-voltage-driven thin film electroluminescent devices are developed by using lowxesistivity stacked film SiO2/Ta2O5 and Al2O3/Ta2O5. At 50 Hz sinusoidal wave voltage excitation, its threshold voltage is below 40 V, and brightness is above 200cd/ cm2 at 60 V. Its characteristics of brightness～voltage (B～V) curve and integrated charge～voltage (Q～V) figure are different from usual one. By using a model of space charge- limited- Cur rent, the distr ibution char acter istics of the space charge and electrical field acrosss the phosphor in the device are analyzed, the mechanism of low-voltage-driven thin film electroluminescence, and the characteristics of B～V curve and Q～V figure are well explained. It is considered that the electroconductivility of the stacked film is the key of low-voltage-driven thin film electroluminescence.

It is essential for realizing color constancy to acquire color descriptors that are not affected by illumination and geometry conditions. To combine dichromatic reflection model with the finite dimensional linear model to derive the normalized deviation body reflectance, has been demonstrated to be an important method to realize color constancy.In the present work, we studied the properties of the normalized deviation body reflectance, its computational method, as well as constrains of its application.