For an atom under the action of ω 2ω two color fields, the phase effects of ionization process in different ionization regimes are investigated. The dependence of ionization possibility on relative phase is found in tunneling regime being a shape of "∩", while in the over the barrier regime being a shape of "∪". Our results demonstrate the possibility of phase control of ionization process by using two color fields.

Based on the coupled mode theory, second harmonic generation (SHG) in the form of Cherenkov radiation from a channel waveguide has been investigated taking the propagation loss into account. The results show that the conversion efficiency has an exponential behaviour and a saturation characteristic, which differ from the linear behaviour in the case of omitting the propagation loss. The results play an important role in the design and fabrication of Cherenkov frequency doubler.

A quantum theoretical model for the system of degenerate three wave mixing has been established. The dynamical behavior and the features of the optical quantum non demolition (QND) measurement were studied by using nonlinear quantum optics. The results show that the efficient QND measurement can not be well performed at the operation of the nonlinear double resonances (NDR) but the nonlinear transformation of the bistability.

Anisotropic self diffraction in doped KNSBN crystals for the anisotropic experimental configuration is studied experimently and theoretically where the c axis is perpendicular to the incident plane. The set of coupled wave equations and its numerical solutions taking the first two order space charge field into account are presented. Both theoretical analysis and experimental results show that anisotropic self diffracted light originates from the contribution of both incident beams.

Impulsive stimulated Raman scattering (ISRS) was applied to some ferroelectric crystals to analyze the vibration of the crystal lattice in time domain. For significant phonon excitation to occur,the excitation pulse duration τ<2 π/ ω α. Using Ti∶Sapphire regenerative amplifier system as a light source, phono polariton oscillatory modes in LiTaO 3 could be observed. The method was applied to KH 2PO 4. Only relaxing was observed within 50 K from the ferroelectric phase transition point. The relaxation time constant τ 0 is 1.33×10 -13 s in the wave vector q=6848 cm -1 . It shows a relaxational character of the ferroelectric phase transition KH 2PO 4.

The focusing properties of a red far detuning high power standing wave for a thermal atomic beam are studied through numerical simulation. The result shows that this type of standing wave is possible to be used for atom lithography. The FWHM of the line width deposited on the substrate at the focal plane of the thermal atomic beam is about 20 nm, the contrast is 4～5, with beam waist w 0=0.1 mm, power P=7 W respectively. A proposal of using enhanced cavity to increase the line contrast to 7 and decrease the FWHM of the line width to 5 nm～10 nm is put forward.

The squeezing of light in the system of two mode squeezed vacuum field interacting with a two level atom within and without the rotating wave approximation by means of quantum theory is studied. The numerical results indicate that the light field is squeezed periodically. Moreover, the squeezing of light field is restrained by the virtual-photon process and relates to the initial state parameters and the properties of the system.

Generalized coherent states of a non harmonic oscillator in a finite dimensional Hilbert space are constructed and some quantum statistical properties are studied. Their squeezing effect and antibunching effect are discussed in detail. The condition of squeezing is found, and the relation between antibunching effect and the dimensionality of the Hilbert space is shown by using numerical calculation. Theoretical calculation shows that the coherent states present squeezing effect and antibunching effect, and these quantum statistical properties are very different from those of usual generalized coherent states in infinity dimensional Hilbert space.

By introducing the temporal correction coefficient, which is defined as the ratio between the closed loop wavefront residual error and the open loop error induced by atmospheric turbulence, and the measured signal to noise ratio, the temporal correction effectiveness of adaptive optical system for light wave atmospheric propagation is studied. Its dependence on the power law exponent of the turbulence, the cut off frequency, the measured signal to noise ratio, the time delay and the closed loop bandwidth is analyzed. The optimal closed loop bandwidth is given. The temporal compensation effectiveness of 61 element weak light adaptive optical system is also analyzed.

The effect of signal pulse shape on the transmission performance is studied for an optical fiber communication system with cascaded in line optical phase sensitive amplifiers (PSA′s) having phase shifting between pumping and signal light. Computer simulation shows that at different phase shifting the eye pattern degradation of high speed signal increased rapidly with the accretion of fiber dispersion, and changed with signal pulse shape for given fiber dispersion. From the simulating results, it is known that signal pulse shape also affect the system performance. The system transmission performance of using super Gaussian pulse is superior to that of using Gaussian pulse, and super Gaussian pulse has an optimum pulse exponent for best transmission performance.

All optical bit clock extraction technology based on fiber cross phase modulation effects is illustrated and analysed. Intensity and pulsewidth of incident signal, the length of dispersion shift fiber (DSF) and walk off between incident and clock signal influenced the output clock intensively. The relations between them are discussed and the chirp character of clock signal is analysed.

A novel bromoboron trinitro subphthalocyanine (BTN SubPc) thin film has been developed by vacuum evaporation for write once optical recording. The absorption and reflection properties of the sublimated BTN-SubPc thin film are pretty good at 500 nm～650 nm, which matches well with the wavelength of semiconductor laser used in digital versatile disk (DVD) systems. The optical recording performance of the BTN SubPc/Al multilayer shows that high reflectivity contrast (>30%) can be obtained at lower writing power (<10 mW) and shorter writing pulse width (300 ns) by using a He Ne laser (632.8 nm) irradiation. The results demonstrate that subphthalocyanine is a promising material for short wavelength optical recording, especially used as recording medium of DVD Recordable (DVD-R).

The dependence of the optical properties on the thickness of AgInSbTe phase change films is investigated. The reflectivity, absorptivity, thickness and optical constant of the films were measured. The change of the extinction coefficient and refractive index become significant when the film is very thin, and become larger at shorter wavelengths such as in blue and green region. These results are very useful in improving the accuracy of optical design and simulation of AgInSbTe phase change optical disks, as well as in the study of phase change optical disks at shorter wavelengths.

The optical sensitive characteristic of SnO 2 and VO x thin films to the gas SO 2 is investigated with photometric and ellipsometric methods. It is found that thin films of the Pd doped SnO 2 and no dopant VO x have good optical sensitive characteristics to the gas SO 2 in the visible range, and the Zr doped SnO 2 film in the near infrared area. The results show that the change of the optical characteristic is directly related to the variation of optical gap and the concentration of free carrier in the thin films.

Laser induced collision energy transfer (LICET) for transition from Eu (6s6p) 8P 9/2 to Sr (5s10s) 1S 0 is observed at fluorescence 458.42 nm and with the peak transfer wavelength of 459.75 nm.The quasi static wing of LICET is observed and the dependence of the excitation function spectral on the temperature and the intensity of transfer laser is investigated. The experimental cross sections of LICEF is measured and the asymmetrical spectral line of LICET is confirmed.

Heat absorption of high power laser windows is analysed and the heat equation of the window for practical working device and its solving condition are given. Physical state of the high power laser is simplified suitable for the pratical condition. Analytic solution of the heat equation is given. Then the thermal lens effect of high power laser windows is calculated considering the thermal changes of refractive index of the window material and linear expanding index, and the result is disscussed.

The influence of external optical injection on the threshold current of external cavity laser diode with fiber Bragg grating is investigated experimentally. In order to obtaining high extinction ratio and high conversion rate simultaneously, the injection current range is determined. The experimental results are analyzed by carrier depletion mechanism.

Wavelength dependence of reflectivity at AR coating facets has been taken into account to study the wavelength tuning range of the external cavity semiconductor lasers. By applying the equivalent cavity method, an analytical expression for the threshold carrier density varied with wavelength has been derived. Analysis shows that the deviation between the wavelength of minimum reflectivity at the AR coated facets and that of the gain peak before AR coating is a key parameter to increase wavelength tuning range.

By using of effective medium theory, the reflective efficiency of two dimensional surface relief structure is computed and analysised in various conditions through computation of rigorous coupled wave method. Several curves are presented in various conditions. Effective medium index of that structure is computed when plane wave normalized on the structure. It is indicated that variation of orientation and polarization angle make less effect on reflectivity for both symmetric or asymmetric structure. The result giving characteristic of anti polarization and anti reflective is obtained. The bandwidth limitation is analysised and its magnitude is given. While, the effect of manufacture error of relief height on reflectivity is analysised. It has a certain instruction significance to the practical work.

Based on the interferometric demodulation technique, a fiber Bragg grating sensor system employing an unbalance wavelength scanning Michelson interferometer to transpose the strain related spectral signal into phase signal is reported. The strain can be recovered by measuring the phase change of the signal with a phase-meter. Experiment demonstrated that the sensing sensitivity of this system with a resolution of 5.5 nε is 1.80° /με. It basically matches the prospected value of 1.83° /με.

The unified coupled mode formalism derived from Maxwell′s equation is employed to analyze the Bragg grating assisted optical fiber symmetric couplers. In the theoretical analysis, the coupling effects due to Bragg grating and coupler are both considered in the Bragg grating region, which is distinct from the previous published approaches. The simulating results verify that the theory can give more accurate explanation to various experimental phenomena.

A statistical optimum design method suitable for wide waveband wavelength insensitive coupler (WINC) is proposed. Using the method, silica waveguides type 50% and 20% coupling ratio WINCs are designed with the optimization of the polarized light fluctuation. The design results are verified by the 3D BPM simulation, and show that the coupling ratios of (50±2.1)% (the polarized fluctuation <0.65%) and (20±1.4)% (the polarized fluctuation <0.20%) in a wide wavelength region of 1280 nm～1650 nm are realized, respectively.

On the basis of the effective medium theory (EMT), both one dimensional and two dimensional periodic structures of antireflection surface are investigated and anlyzed. The 2 D relief structure pattems for antireflection are designed and fabricated on silicon wafers by binary optical processing methods. This 2 D structure can be used as an alternative to thin film coatings to enhance transmission at the boundary between two different media.

The main diffraction properties of a soft X ray optical component--multilayer gratings are deduced and discussed in detail on the basis of X ray kinematics. Results show that main energy of diffraction light can be concentrated in one order and resolving power and reflection of multilayer grating are higher. There is essential difference between the dispersive properties of multilayer gratings and multilayers.

Theoretic analysis and numerical computation on film attenuator of variable angle are studied. The attenuator is ready to be used in SHENGUANG Ⅱ precision project. The characteristics of precisionly continuous adjust, large optical aperture, high energy loading and high beam quality are demonstrated in simulation experiment. Other optical attenuators can not provide with these characteristics solely.

L625 Mie lidar and data processing for measuring stratospheric aerosol are described. The results show the good agreement with those of American NASA/SAGE Ⅱ satellite observation. Long-term variations of aerosol extinction coefficients and integrated backscatter coefficients in the stratosphere during the years of 1991～1998 are preliminarily analyzed.

The photo bleaching processes in a nonlinear optical polymer film used poly (methyl methacrylate) based dispersive red one (DR1/PMMA) side chain at 488 nm argon ion laser radiation was investigated. The index change of DR1/PMMA film was measured by two beam scan technique. It provides a simple method to determinate the parameters in bleaching model describing the photo bleaching processes of polymer.

A novel high power self starting mode locked Ti∶sapphire laser with a semiconductor saturable absorber mirror (SESAM) as self starting element is demonstrated. Its sloping efficiency is 22%, average power as high as 1.7 W and pulse width shorter than 16 fs. The starting dynamical process of the laser has been studied. This kind of laser will have a wide applications.

The whole nonlinear optical coefficients of GdCOB crystal are evaluated by phase matching SHG method and Maker fringe method. The spatial distribution of effective nonlinear coefficient d eff are proved with the crystals cut in different directions in the experiments. The results show that d eff reaches the maximum of 1.68 pm/V at the direction of θ=66.8°,φ=132.6°. The SHG conversion efficiency reaches 48% with a 6 mm long GdCOB crystal cut along this direction.