The distortion mechanism of high power laser mirrors is discussed. The de formation of water-cooled cavity copper mirror and annular channel copper mirror is tested by a Twyman-Green interferometer and image processing system. And a new kind of copper mirror is proposed. Compared with the other mirrors,the new mirror has not only a small thermal deformation caused by incident laser but also a very small pressure de formation yielded by the cooling fluid.

A self- organized fuzzy control system used for a dual wavelength frequency stabilized CO2 laser with high precision is presented. Because of the very complex operating situation of the CO2 laser, especially the tough condition for simultaneous dual-wavelength stabilization, a series of parameters in the CO2 laser system must be controlled effectively. A self-organized fuzzy control system described in this peper is satisfied for these requirments. Both short and long term frequency stabilities of the simultaneous oscillations are better than several parts in 10 10.

The Space spectra of the apertured Bessel beam are calculated. The Propagation of the apertured Bessel beam is discussed from the view of space spectrum. The critoria of the nearly diffraction-flee beam is: the space spectrum has a non-zero major maximum and the spectrum width are narrow. The Propagation feature can be improved through space filtering.

A novel method for designing binary computer-generated hologram (BCGH) is presented. The principle of synthesizing BCGH by iterative search algorithm is analyzed. A set of parameters are established to evaluate a computer holography algorithm. The reconstruction quality and diffraction effciency of several BCGHs are analyzed in terms of computer analogue. The results show that the phase BCGH synthesized by iterative search alsorithm results in substantially well reconstruction quality and high reconsttuction efficiencies, it's a better iterative algorithm for designing BCGH.

An analysis of the Causes which result in bit errors is given for magneto-optical Storage systems with zero-crossing detection. in consideration of Several kinds of Timing errors. a mathematical model of describing the bit error characteristics in the channel is derived. .Also. an analysis of the relationship of the signal detection method and the bit error characteristics is presented. It is shown that the fault fredom in balanced differential channels is better than that in unbalanced differential channels.

We have discovered a third welding Process-unstable-mode welding (UMW)under a certain condition, apart from the already known stable deep penetration welding (DPW) and stable heat conduction welding (HCW) in a high-power laser welding. UMW has a basic feature that the two welding modes (DPW and HCW) appear intermittently with extremely varying penetration depths and welding widths. In this peper, offects of welding parameters (focal cosition, laser power and moving speed) on laser welding mode and weld forming have been comprehensively studied. Double-U curves of laser welding mode transition have been obtained, which can be used to determine the process parameters of the three mentioned welding processes.

A UV laser at 266 nm wavelength was used to excite target tissues. Laser-induced fluorescence spectra of several kinds of vascular tissues and individual layer vessels were observed. The major factors which influence the spectral characteristics were analysed. The LIF diagnostic criterions on human normal aorta and Pathological changes are suggested.

A cellulase Producing fungus aspergillus niger was mutugenized by copper vapor laser irradiation. Four mutant strains of high cellulase production were selected. When they were cultivated in straw-wheat bran solid medium at 28～30 ℃ for 96 h, the highest enzyme activities were as follows: CMC enzyme activity (Cx): 2839 mg Glucose/g·h, Filter Paper enzyme activity (CL): 299 mg Glucose/g·h, and β-gluccoidase: 1091 mg Glucose/g·h. In addition, some characteristics of No.78 strain, such as morpholopgical character, development, fementation cycle, and stability of enzyme production, were tested. These results were ideal and showed that laser matagenesis was one of the useful mutagenetic techniques newly applied to microbial breeding.

We studied the second and thitd order dispersion of the dielectric cavity mirror in femtosecond Pulsed lasers. The amount of dispersion can be a function of its construction Parameters and the angle of incidence. The second and third order dispersion iS increased with the ratio nH/nL and the number of lapers. The thied order dispersion begins to oscillate when the ratio nH/nL and the number of layers are in excess of 1.67 and 25-layer respectively. Moreover, we conclude that the effect of incident angle on the third order dispersion is very important.

An analytical expression of the steady-state laser output intensity of a bistable semiconductorlaser of output- feedback loss-modulation has been obtained from rateequations. Using a CCTS GaAs/AlGaAs SQW semiconductor laser, we have observed the bistability arising from output feedback loss modulation in the semiconductor laser. Compering the theoretical curves of bistability obtained from the rate-equations with the experimental P8tt6rns of bistable Characteristics, we found that there is a good agreement between the two kinds of bistability curves when the device's parameters (for example, feedback loss-modulation coefficient et al.) are changed.

An excimer laser pumped tunable 30 ps dye laser with a quenching cavity is reported.

We demonstrate a novel electro-optical Q-switch technique. An electro-optical etalon is used as the laser output mirror. There are three features of this etalon: output coupling, Q-switching, and mode selection. The thermal effect of laser medium on etalon reflectivity is studied and the optimization of etalon reflectivity is discussed with a laser rate equation.

The electro- optic characteristics of a discharge excited strontium-ion recombination laser have been analysed and measured. An average output power of 200 mW is experimentally obtained.

The building of the phase grating and the distribution in the interaction region in photorefractive TWM are studied in the condition of depletion. The dynamic properties ofthe grating and the output of the signal are investigated theoretically and experimentally.

In the far field, we analyse the spatial and temporal characteristics of ultrashort Gaussian pulses by expanding them into monochromatic Gaussian beams. Spectral shift and pulse-front curving caused by space-time coupling were studied.

Based on the measurement of time evolution of the Stark brodening of the spectral lines of Mg atoms and ions from a laser induced plasma, the time evolution character of electronic density in the laser induced plasma was obtained and a mechanism was suggested.

The shock wave generated by plasma under the condition of local absorption is studied in this peper. Applying the Plasma ablation mode and critical density profile jump model, we develop a complete, self-consistent system. Fluid parameters characterizing the process are derived and expressed as functions of the ratio of the light and thermal Pressure.

Photorefractive properties of heavily reduced Ce:Fe:LiNbO3 at 633 nm have been studied. The photorefractive sensitivity of this crystal is about 400 mJ/cm2. The twobeam coupling constant is about 45 cm-1. The resolution of a Fourier transform hologram recorded with this kind of crystal reaches 70 lp/mm.

The preparation procedure of (F2+)H centers in sulfur-doped NaCl was describe,and the stability of (F2+)H centers in the dark at room temperature was also measured. This Paper discusses the stabilities of S2- on F2+ centers, the defect reaction during Process, and POints out that the concentration of F3 centers must be kept as lower as possible during quenching in order to obtain high concentration of (F2+)H centers. It is Proved that the transient absorption due to F2+ centers during light aggregation can not be absolutely avoided, and thus increases the no-laser-active loss. The exposure dosage during aggregation is one of the major controllable paramaters to obtain a high qualitative crystal.