Temporal power spectra of low-order modes［tilt(Z-tilt, G-tilt), defocus, astigmatism, coma］ of atmospheric turbulent wavefront are deduced by introducing generalized phase spatial spectrum. Numerical results and analysis are given under the conditions of horizontal atmosphere, observation of star objects and monitoring of spatial objects. The results show in horizontal atmosphere, the temporal power spectra is proportional to the 4/3-6β/11 power (β is the power-law exponent of phase power spectrum) of the frequency v for tilts and v0 for defocus, astigmatism and coma for small v values respectively. For large v values, all the spectra have the same asymptotic behavior and decrease as v-β-2 except for G-tilt whose power spectra decrease as v-β in horizontal atmosphere. The temporal power spectra is influenced by outer scale of atmospheric turbulence and with the decrease of outer scale, the spectra becomes steeper and steeper.

A new approach for demodulation of the multiplexed fiber Bragg grating sensor system based on the use of wavelength-matched fiber grating tuned fiber laser to interrogate the sensing gratings is proposed. The response characteristics have been analyzed theoretically. Experimental results of three grating sensors multiplexed system are presented for temperature measurement, which agree well with theoretical ones.

The transmission spectrum of long period grating was analized by a combination of coupled mode theory and transfer matrix method. It is suggested that a phase-shifted long period grating can be used to flatten the gain spectrum with two peaks, and the result proved that such gain flattening is plausible.

A novel stratification method (staircase approximation method) is presented to analyse dispersion characteristics of nonlinear slab sandwitched between linear substrate and linear cladding. Recursion formulas which are equivalent to extended transfer matrix method are used to calculate the dependence of propagation constant on power density. The method can be applied to non-Kerr type films as well as slab guide with graded-index. Computed results for typical examples are in good agreement with the exact results reported in literatures.

Absolute difference measurement (ADM) is introduced into joint transform correlator (JTC) for optical gray-scale image matching. Using a novel cycle encoding method, ADM is performed on a JTC in one step. With a high-level thresholding value, the correct justification can be achieved from the correlated resultant image. The value of thresholding should be changed according to the different situation of noise disturbing so that it can improve the distortion-invariant ability of the JTC system. The simulation results are given.

The restriction on white light source and colour filter in a colour joint transform correlator (CJTC) is discussed. Based on this discussion, a new method of channeling using a three-color grating for pattern encoding is suggested. It is concluded from the experimental result that, by using this new method, not only the restriction on the experimental condition is relieved, but also the power spectra of the encoded pattern are easy for experimental processing in parallel channeling. Besides, the zero order power spectrum forms an important channel for the shape-only correlation.

Based on the study of the thresholding method of the morphological rank order hit-miss transform (ROHMT), a one-channel rank order hit-miss transform is proposed and a rank order grayscale erosion is developed to implement the ROHMT and its extension. Compared with the conventional complement encoded hit-miss transform (HMT). Only the original image is used. Based on this implementing scheme, the HMT-based morphological processing systems can be greatly simplified; Its immunity to noise and processing capacity are both increased. A proof-of-principle experiment is conducted and the experimental result is given.

3-D profilometry based on modulation measurement (MMP) depends on the modulation distribution of the sinusoidal fringes projected on objects. The projecting direction is the same as the detecting direction, it can measure the objects with shadow, discontinuous height steps and spatial isolation on them. The detailed introduction on the principle and processing method of MMP and the measuring results for an object are presented. The results proved that MMP was correct in principle and effective in actual measurement. This method will be useful for 3-D profilometry、 3-D sensing and machine vision etc.

In the opto-electric imaging system, aliasing will occur when sampling a scene containing spatial frequencies exceeding half of the sampling frequency. Microscanning is a potential method to reduce aliasing effect. Mathematical theory for microscanning based aliasing reduction, including non-even cases, is analysed. Computer simulation of microscanning realization for both one- and two-dimensional cases is presented.

A differential displacement system using the self-mixing interference effect in a laser diode and its model is established. It is confirmed by computer simulating and experiment that the resolution of this system is two times of that of common single laser diode system. The intensity noise and temperature disturbance can be decreased greatly.

The image transfer based automatic laser alignment technique is a good way for improving the alignment accuracy and increasing alignment stability. The effects of this technique on the image processing is analyzed theoretically by two dimension FFT simulation. The matched cross-hair width for one spatial filter in “Shenguang Facility” is calculated. A detailed image transfer based alignment system is given.

An absolute distance heterodyne interferometer using a dual-longitudinal mode He-Ne laser is proposed. In this interferometer an optical heterodyne technique is used to enhance the signal/noise ratio of its opto-electrical signals. By measuring the phase difference between these two heterodyne signals, the fractional fringe of the synthetic wavelength is measured precisely and directly. Also the influence on the measuring accuracy from the mode coupling is analyzed. The compensation for this error is discussed. An accuracy of 140 μm in 25 m is obtained.

Starting from the four-level laser rate-equations with spatial dependence of both the pump beam and the cavity beam, the corresponding relations between input and output parameters in diode side-pumped solid-state laser are obtained. The influence of spatial variations on output performance is analyzed. The optimum parameters are found out.

An open resonator composed of a cylindrical mirror and a diffraction grating centering at the wavelength of 10.6 μm is investigated by utilizing the Fox-Li iterative method. The near and far field distributions of the eigenmodes and frequency selective loss function are calculated numerically.

The output characteristics of fiber ring lasers composed of different length Er-doped fiber (EDF) and different split ratio output couplers are studied experimentally. According to the experimental results, it is concluded that the threshold and slope efficiency of the laser are related to the length of EDF and the split ratio of the output coupler. Both of them have one optimum value.

Based on the Maxwell equations and Poyingting vector theoresm, a new thermal design method of magneto-optical (MO) multilayer is presented taking the laser-radiated TbFeCo quadrilayer as an example. Compared with the conventional design method, the new method not only cosideres the practical need of tracking servo, but alse shows great efficiency in calculation. It implies that this method can be used to the structure designing of other multilayers. According to the new designing, a TbFeCo quadrilayer was successfully made using the dc sputturing methed. Corresponding static and moving measurements are carried out, which show good effects of reading and writing.

Several physical and technical factors that influence on the topography of weld in deep penetration laser welding were investigated theoretically and experimentally. Suggestions on technical methods of laser welding are put forward to improve the quality of the weld surface.

By using photoluminescences (PL), the molecular beam epitaxy (MBE) grown Hg1-xCdxTe (x=0.32) epilayers are studied. The PL measurement shows a strong near band edge emission peak with an FWHM of 5 meV and a small broadening energy, E0(4.2 K)=1.3 meV, which indicates the high quanlity was obtained. Comparing the results of as-grow and annealing sample shows that annealing sample has a better crystal quality than the as-grow sample.

The numerical results about the photon statistics of the chaotic light field in third-harmonic generation are given. The photon statistics of the chaotic light field obeys the super-Poisson distribution. In all cases, the photon statistic fluctuation of third-harmonic wave is always stronger than that of the fundamental wave. This fluctuation vary irregularly with the increase of the the maximum Lyapunov exponent of the system.

A novel displacement encoder employing a sine micro-window grating is developed. It features high quality signals free from harmonic errors. The sine micro-window grating is a special component composed of arrays of micro-elements with a sine window at the center of each element. The prototype is successfully manufactured by employing optical pattern generator and lithography technology and practically used in the design of an optical encoder. Experiments show that the harmonic errors of encoder signals is reduced to less than 2% of the fundamental wave.

The focusing properties of the varied line-space plane grating was described by using the light path function. A varied line-space (VLS) plane grating for soft X-ray use was designed. The performance of the VLS grating was computed by using a ray-trace procedure, and the result was satisfactory.

Based on the partial differential equation related to the displacement of bimorph deformable mirror with free boundary condition and its applied voltage deduced by S. A. Kokorowski, a matrix of static response functions f(r, θ) of mirror is derived with Gaussian iteration. Considering the statistical weight factors of different Zernike model aberrations caused by atmospheric turbulence, and the different arrangements of mirror positioning, the optimization of the bimorph deformable mirror is analyzed. The results indicate that, the correction capability of bimorph deformable mirror is greatly dependent on the statistic weight function of the corrected Zernike model wave aberrations induced by atmospheric air turbulence, so far as to the optimization design of mirror. And the different ways of mirror positioning will slightly affect its correction capability.

The electric-optical performance of a hometropic aligned liquid crystal light valve (LCLV) as the function of light valve parameters and operating conditions is simulated numerically. This simulation is based on the 4×4 matrix formalism which is the exact numerical solution of Maxwell′s equation. The effects of liquid crystal (LC) thickness, incident angle and the pretilt angle on the electric-optical performance of LCLV are discussed. Based on the Oseen and Frank′s continuum theory of nematic liquid crystal, and generalized torque balance equation at the interfaces, the director configuration and the electric-optical performance of a hometropic aligned liquid crystal light valve as the function of light valve parameters and operating conditions are calculated. The effects of anchoring strength of Nematic Liquid Crystal (NLC)-wall and the pretilt angle on the director configuration and then the electric-optical performance of LCLV are discussed.

A new way to calculate the quantum yield of negative electron affinity (NEA) photocathode is introduced. On the base of “three-step emission model”, the quantum yield of NEA photocathode is obtained by integral. The quantum yield formulas of reflection-mode and transmission-mode NEA photocathode are given. The formula of reflection-mode photocathode is the same with that derived from the diffusion equation. And, according to the formula of transmission-model NEA photocathode, thoretical quantum yield curve is drawn by computer, which is coincident with the curve drawn according to traditional formular and also identical with experimental curve.

The effect of doping with copper and chlorine on various properties of vacuum-evaporated CdS and CdSe doube layers has been studied. The properties specifically studied including: (1) the dark conductivity and photo-conductivity as functions of the doping concentration and the radio of copper to chlorine, (2) the response time of various photo-conductive films and (3) the spectral response. It was found that the dark conductivity decreases and the photo-conductivity increases significantly if the ratio of Cu to Cl is suitable. The response time was about 5～10 ms for doping films and more than 100 ms for undoping ones. The optical absorption increases and the spectral response moves to a longer wavelength as the concentration of CdSe increases. The response wavelength can be changed by adjusting the thickness ratio of CdS to CdSe.