An electron beam can be injected into the interaction region of a free-electron laser adiabatically or non-adiabatically. Non-adiabatic injection can induce axial velocity fluctuations, therefore adiabatic injection is preferred. For free-electron lasers with axial magnetic fields, initial perpendicular velocities can induce axial velocity fluctuation too. In order to reduce the fluctuation amplitude, a step-like axial magnetic field can be applied for cooling perpendicular temperature of the beam, and proper selection of system parameters is necessary.

The effects of different velocity ratios of two parallel gas flow and the uncertainty of kinetic rate coefficients on the characteristcs of HF chemical lases are investigated. It is shown that the collisional relaxation process of HF(v)-H is so fast that the variation of its rate coefficient have significant influence on the gain characteristics.

The characteristics of an XeCl excimer laser using magnetically assisted switch techniques were investigated. The pulse rise time discharge current was compressed from 200ns to 50ns, and the amplitude of reversal current was reduced extraordinarily. These results are in good agreement with theoretical calculated ones. The effects of by-pass inductance on the compression were discussed.

AN unstable cavity injection mode-looked TEA-CO2 laser with 1 m long gain medium is described. It can operate in single longitudinal mode without adjusting cavity length, Under some conditions injection mode-looking happens even two lasers individually oscillate in different brancies.

A new effect was discovered in welding thin metal plates with a low power CO2 laser. In the welding process, a small hole exists in the welding puddle and penetrates the plate. This effect was proved experimentally for the first time The conditions of power and energy density were also investigated experimentally and theoretically.

This paper analyses some typical exciting conditions in optical fiber measurement and proposes a new equilibrium mode distribution method, in which a "S. S. F." mode stripper is used to improve greatly the measurement accuracy of the fiber loss. It provides an effective and reliable exciting method for accurate measurement of optical fiber parameters.

A method for eliminating wavefront aberration, used in phase difference amplification was proposed. Two holograms were inserted in two optical paths of a Mach-Zehnder interferometer respectively. One of the holograms recorded the information of both object phase and wave-front aberration of the system, the other recorded only that of wavefront abarration. While reconstructing, the wayefront abarratioa could be eliminated and the amplified phase difference obtained. The experimental results were given finally.

Irradiating graphite in hydrogen atmosphere with XeCl excinier laser light, some hydrocarbons, i. e. CH4, C2H2, C2H4 and C2H6, were formed. The possible mechanism was discussed.

Gadolium gallium garnet crystals substituted with Ca,Mg, and Zr and doubly-doped with Nd and Cr are grown, and their laser properties are investigated. Transparent and perfect boules measuring ψ18×60-80mm are grow n by means of Gzochralski method using iridium crucible and inducting heating. Laser rods of the size of ψ5 × 40mm are machined. The output slope efficiency obtained was 0.7. Comparison of spectroseopic properties and lattice constant of the crystal with those of GGG crystals doubly doped with Nd, Cr and substituted with a small amount of So is made and a discussion is given.

Intensity parameters Ωλ(or τλ) of Er3+ in crystal ErP5O14 were calculated by Judd-Ofelt theory. With these Ωλ valus, the oscillator strength, spontaneous radiative transition rate,seadiative lifetime, branching ratio and integrated emission cross section were calculated. In comparison with integrated emission cross section of certain laser crystals such as YAlO3:Er3+ and-CaF2:Er3+, the potential application of ErP5O14 as laser material was discussed.

The genetic effect of three stocks of D. melanogaster, C. S., Base, and bw-st/bw-st were studied with irradiation from He-Ne, nitrogen and argon ion lasers. Experimental results show that when the radiation dosages of He-Ne laser, nitrogen laser and argon ion laser amounted to 32J/cm3, 0.75J/cm2 and 196J/cm2, respectively, genetic effects of recessive lethal mutation and translocation have not been observedyet.

Mark Ⅲ system provides both fringe measurement technique and phase measurement technique to perform optical wavefront measurements for wide spectroscopic application. Optical plates, spheres, lens systems and optical materials have been tested with fringe and phase measurement techniques.

Laser dye carbostyil 124 was synthesized. The spectral and laser properties of it were given and the tunable wavelength ranging from 400 to 438nm, with λmax at 419nm was found. Com-pare with coumarin 120, the wavelength is blue-shifted and the efficiency is lower.

UV laser emission has been obtained by metal piece discharge generated plasma as preionization source and main discharge cathode.

Spectrum of higher states, excited from 6P2 to S and D states in Cs atoms by optogalvanic spectroscopy are measured and the experimental results are compared with the calculated ones.

Variation of some medical parameters of the human heart function before and after He-Ne laser irradiation is reported. It shows that LVEF of the patients with coronary heart disease and non-coronary heart disease has been increased obviously (P 0.05) after some parts are irradiated.