The arrection method of two adaptive optics (AO) systems in series was put forward. An AO system with feed forward control loop was connected to an AO system with feed back control loop by a community wave front corrector. The control performances and the transfer characteristics of noise by this method were analyzed. The method of two AO system in series isn′t much more complex technically than normal method of single AO system, but the control performance of the two systems in series is improved greatly in comparison with single AO system. The simulation results with practical experimental data on the 61-element AO system verify the availability of the method.

An experimental system for time resolved optical tomography is constructed by Ti∶Sapphire laser and syncroscan streak camera. With 3 dimensional step motor driving stage, the system can scan the object to be imaged in a parallel beam mode analogous to X ray CT, by which the time resolved projections at different incident angles can be obtained automatically. By applying the relevant image reconstruction algorithm, the promising images have been produced from the measurements for three kinds of tissue like phantoms that represent the different combinations of the absorption and scattering properties of the embedded single inclusion. The results indicate this system as a reliable and ideal platform for optical tomography research.

A numerical program, which combines Monte Carlo method with geometrical ray trace used to study the behaviour of multi photon excitation (MPE) fluorescence microscopic imaging through turbid media, is presented. The mathematical model used to microscopically image multi layered tissues is presented. The basic skeleton of the simulation program is demonstrated with flow chart. A skill is introduced to improve the traditional Monte Carlo method, which enhances the capability of simulation of the converging light. The prominent effect on microscopic imaging caused by scattering characteristics of turbid media is shown through preliminary simulation experiments.

The effect of the deviation between the center of collimated laser beam and the center of the phase plane on the diffraction pattern is investigated and simulated. A novel diffraction pattern processing method based on multi layer feedforward neural networks is proposed, which is proved to be better than the conventional method based on the least squares curve fitting. Moreover, the method proposed has the potentiality to be used for processing such complicated image as diffraction free beam with high precision.

The self mixing interference effects in a laser diode with multiple optical feedback are studied. The system model is established based on the compound cavity effect in lasers. The numerical analysis of the model is accordant with experimental results. The results contribute to the theory of self mixing interference and to the designing of a displacement measurement system with high resolution.

A small sized flat field grating spectrograph was developed by using a varied spacing concave grating with a nominal groove spacing of 1/1200mm and a radius of curvature of 5649 mm. The incidence angle and the object distance of the spectrograph are 87.45° and 155 mm respectively. The spectrograph was used for test in "XINGGUANG Ⅱ" laser system, and the experimental results showed that the spectral resolution of this spectrograph was better than 0.015 nm for time integrating detection with film.

Aiming at the improvement of the normal diffraction technique, a kind of new method is presented. The reflection is introduced to form mirror image. By this way, the light intensity distribution of the diffraction fringe can be changed to improve the measuring accuracy, increase the dynamic range, and restrain the degradation of the field distribution caused by the unevenness of the slot. The parameter preferences are discussed.

A new method for real time and controllable laser beam shaping using liquid crystal spatial light modulator (LC-SLM) is presented. The optical modulation characteristics of LC SLM are studied. An optical system that consists of a soft edge serrated aperture formed by LC SLM and a filter could effectively convert an arbitrary profiles beam into a flattop intensity beam with a high fill factor in the near field.

A method of using Brillouin scattering technique for measuring directly the bulk viscosity of water is proposed. By analyzing the relationship between the line width of Brillouin scattering and the shear and bulk viscosities, a relation of the bulk viscosity of water with the line width and frequency shift of Brillouin scattering is suggested, which is the basis for determining bulk viscosity experimentally. The experimental data of bulk viscosity of water at different temperatures were given. The testing error of this method is analyzed. Both of theory and experiments show that Brillouin scattering technique is a quick and accurate method for measuring bulk viscosity of water.

The characteristic of the intensity noise of LD pumped single frequency ring Nd∶YVO 4 lasers is theoretically and experimentally investigated. The resonant relaxation oscillation (RRO) in the noise spectrum of laser output is strongly suppressed by a self designed negatively opto electronic feedback system. The intensity noise around the peak of RRO (300 kHz) is reduced about 25 dB.

By scanning the cavity length of optical parametric oscillator (OPO) with tri angle wave voltage of different scan rate applied on PZT, the thermal effect of nonlinear crystal in OPO was observed. The experimental results show that the thermal effect seriously affects the peak power of output pulses at the resonance points, therefore it can be used to demonstrate the thermal self frequency locking of the OPO. The physical mechanism of the observed phenomena is reasonably analysed.

The methods for completely measuring the timing jitter of passively mode locked Ti∶sapphire laser are proposed. It is demonstrated that for the laser system with smaller timing jitter, frequency domain measurement is the major method, whereas for the system with larger timing jitter, frequency domain measurement is not suitable. Instead of that the method of using synchroscan streak camera is more precise. With the technique of actively cavity length controlling, the timing jitter of passively mode locked Ti∶sapphire laser has been reduced from 6.6 ps (before controlling) to 0.47 ps.

A new type of organic polymer nonlinear optical compound filmPolypyrrylarylenemethine/polyvinyl is prepared. In the Z scan experiment, two different types of concentric diffraction rings are observed in the far field depending on the position of the sample relative to the Gaussian beam waist. This phenomenon can be explained by the diffraction effect of the Gaussian beam from the laser induced phase hole in the nonlinear medium caused by Kerr effect and thermo optic effect. Based on Fresnel Kirchhoff diffraction integral equation, a mathematical model on the diffraction of nonlinear optical media to Gaussian beam is established. The numberical calculations give good agreement with the experimental results.

Pt 1-x Mn x /Co multilayers were prepared by magnetron sputtering method. The crystal structrue was analysed by large and small angle X ray diffraction. The ralationship between structure and magneto optical properties in PtMn/Co multilayers was studied. Through measurement and analyses, the Kerr spectrum, Kerr ellipticity spectrum and Kerr loop shown the changing rules with the increase of doped Mn concentration. The physics mechanisms are discussed.

The ionization spectrum of potassium atom is investigated by 4 2S 1/2 6 2S 1/2 two photon resonant excitation. The resonant exciting laser wavelength is 728.4 nm. The ionization spectrum as a function of temperature and laser intensity are discussed. When the temperature of potassium vapor comes to 643 K, the ionization intensities reach the maximum. And the ionization intensities are saturated while laser intensity increased to 4.5×105 W/mm2. The spontaneous spectrum of the 6 2S 1/2 4 2P 1/2,3/2 is also observed.

A novel scheme for polarization insensitive optical wavelength conversion based on four wave mixing (FWM) in semiconductor optical amplifier (SOA) is proposed and demonstrated. An all optical polarization state converter which can automatically change random input polarization state into linear output polarization state with fixed polarization direction and power is employed in wavelength converter. Using it to control the polarization state of signal beam, the intrinsical polarization sensitivity of FWM process can be overcome simply.

Significant intensity-dependant self-diffraction of octa PdPc doped ormosil was measured under the illumination of CW Ar + laser beam. Optical limiting properties at different wavelengths were investigated. Due to its large optical limiting effect and solid-state processability, this material could have potential applications in constructing optical limiters.

The formula of the intensity on the reflected direction of second hormonic generation circular dichroism (SHG CD) is presented. The relationship between the intensity of surface SHG CD and pitch, radius and azimuthal angle of molecules in helix molecular films are analyzed, and the numerical simulation results are given. It shows that in the value range of pitch or radius, there exists the maximal intensity of SHG CD respectively. And the relation between pitch and radius is different to the varying azimuthal angle of molecules.

Mathematic optimization models of discrete aberration functions and Strehl ratio have been set up, and the relationships between them are analyzed. A quantitative study provides ultimate curve of peak to valley aberration value and Strehl ratio. Ultimate curve of root mean square aberration value and Strehl ratio is presented.

A novel high cost effective 1×7 cylindrical mixing rod plastic optical fiber coupler (CMRC) is proposed. Comparing with conventional tapered mixing rod plastic optical fiber 1×7 coupler (TMRC), 1×7 CMRC using cylindrical plastic optical fiber (POF) as mixing rod instead of tapered POF, thus the high demanding POF tapering process is eliminated and the cost of the coupler is greatly reduced. In order to reduce the crosstalk of 1×7 CMRC introduced by using of cylindrical mixing rod, a U shape optical fiber absorber is placed on the mismatched area on the end face of the mixing rod. Theoretical analysis and experimental measurement indicate that 1×7 CMRC with U shape absorber has a equivalent coupling efficiency as 1×7 TMRC. The measured crosstalk of the 1×7 CMRC with U shape absorber is lower than -40 dB.

A novel large scale all optical star coupler is presented. This star coupler can provide not only a great number of ports for very large scale bidirectional WDM network systems in future, but also the WDM star networks composed of this star coupler have the great flexibility of networking. Its capacities can be expanded conveniently and smoothly on line. At the same time, it also can be adapted in unidirectional WDM network systems used extensively now.

An integral expression for the time domain output response of traveling wave (TW) electrooptic phase modulator is derived by using the scalar wave equation and Fourier transform technique. In the case of a Gaussian modulating pulse, the temporal dependence of the output modulated phase amplitude was calcauated. The plots showing the effect of velocity mismatch and microwave attenuation on pulse shape, amplitude, and width was given. The method proposed is generally applicable to the time domain analysis of TW modulators.

The thin film deposition is used to make 16 step Fresnel lens. It can implement system′s lightweight, miniaturization and increase free degree of the design. Based on the scalar theory the effect of surface reflection of the SiO 2 film and substrate on the diffractive efficiency is analyzed by using Fresnel formula and Fourier transform.It is pointed out that the surface reflection has great effect on imaging of Fresnel lens. The coating is used to decrease this effect.

Transmission properties of Hermit Gaussian optical pulse in the dispersive medium are discussed by moment method and approximate solutions are obtained. The solutions are compared with numerical simulation and the results show that the solutions are helpful to the research of transmission of short optical pulse in dispersive medium.

A widely tunable quasi phase matched optical parametric oscillator was demonstrated by using periodically poled LiNbO 3 (PPLN) with a multigrating structure. With a 1064 nm acousto optically Q switched Nd∶YVO 4 pump laser, a tunable IR output from 1.436 μm to 1.7 μm was obtained. The threshold was 10.3 μJ with pulses repetition rate of 10 kHz. The maximum average output power of signal is 42.5 mW with pump to signal conversion efficiency of 12.5%.

A computer generated holography (CGH) wavefront transforming element is designed and fabricated based on computer generated hologram and binary optical technique,and is applied in head up display. Its diffraction efficiency is very high. The diffraction efficiency of a two phase CGH is four times higher than that of a general CGH. It can generate special optical wavefront, such as aspheric surface, ring shaped surface, cone shaped surface and so on,which the traditional optical elements can not generate. Moreover, the fabrication and duplication techniques of CGH are simple and convenient.

The luminescent properties of Eu3+:Y 2O 3 nanocrystals at low temperature were studied. Emission spectrum of Eu 3+ ions in Y 2O 3 nanocrystals with different size were compared. Based on excitation spectra at various temperatures, the relationship between the intensities of excitation spectra originating from different sites and the temperature has been analyzed. The luminescence decay curves of 5D 0- 7F 2 Eu 3+ (C 2) emission after excitation into the Eu 3+ (C 3i -C 2) pairs and isolated Eu 3+ ions were measured. The results show that the rate of energy transfer from Eu 3+ (C 3i ) to Eu 3+ (C 2) in the case of Eu 3+ (C 3i )-Eu 3+ (C 2) pairs is faster than that for the isolated Eu 3+ ions. The mechanism of quenching concentration increasing in Eu:Y 2O 3 nanocrystals has been discussed.

Using Ar as buffer gas, the collisional influence on two different population ways of high lying state in Na 2 ladder level system is studed experimently. For two photon transition, because of dephasing collision, Doppler free Lorentz peak will vanish via the increasing of buffer gas pressure. Injecting little buffer gas to the cell will enhance the Doppler width signal because of collisional excitation, but too much buffer gas will decrease the signal because of population eliminating effect. For collisional high lying state population, injection of buffer gas will be the key function to high lying state population. The explanation in the term of rate function has been given.