Taking energy and entropy as the main parameters, the changing process and dissipative properties of a laser system both with and without outside influence are considered. With the help of the principle of minimun entropy production, we introduce the phenomenolo-gical linear law to explain quantitatively the relations among the stimulated radiation, the stimulated absorption and the photon number density inside the cavity and to seek the thermodynamic criterion of the steady state of a laser under entropy and energy flux exchange with the environment.

The mode discrimination and loss characteristics of unstable optical resonators with higher Fresnel number are analysed using theories of geometric-optics and interferometer. The parameters affecting the mode restriction ability are discussed.

The change of longitudinal frequency spacing produced by gas lenslike effect has been calculated and mode-locking induced by this change is discussed. To make gas flow or to add more He gas into the mixture, so as to reduce lenslike effect, it is possible to obtain mode-locked narrower pulses. Using proper laser resonator configuration, mode-locking stability can be improved too.

The investigation of a magneto-optic isolator for fiber communication is reported. The isolator consists of a Faraday rotator made of rare-earth iron-garnet single crystal and two calcite prisms. Insertion loss of 2.4 db and isolation ratio of 34.8 db were obtained at 1.15 m wavelength. The improvement of isolator properties by using some rare-earth substituted iron-garnets and polarization-independent techniques are also discussed.

Several types of stresses are analysed in YAG:Nd3+ crystal grown by Czochralski method. It is shown experimentally that the defect stress and chemical stress account for a considerable portion of the total stress. Therefore high temperature annealing has little effect on the illimination of stress, it even leads to the contrary results.

Mechanism for early blacking in alkalimetal vapor lamps, such as potassium-mercury lamp, sodium-rubidium lamp and potassium-rubidium lamp, is discussed, and suggestions for improvement are given.

In the paper, we analyze the disturbance of out-of-plane displacement on in-planedisplacement and suggest a new experimental method——"double speckle interferometry", toseparate the displacement mentioned above.

A CW HCN submillimeter wave laser has been constructed. The structure and the performances of the laser are given. A reflection grating spectrometer and a Fabry-Perot interferometer have been constructed for the measurement of the laser output wavelength with the accuracies of better than 1% and 0.1% respectively.

In this paper we present several methods which use the speckle, Talbot and Moire effects to adjust the position of focus, the collimation of beams and the position of optical elements in the coherent optical information processing system.

This paper mainly studies some defect which were found in melting pool of welding point in the pulsed laser welding, analyses the reasons causing the defects, and discusses methods to eliminate the defects.

Study of laser microbeam irradiation of biological model tissue and the living cells of plants as well as animals such as soybean cell line, protoplast of mesophyll cells in tobacco, Chinese Hamster Ovary Cell Line (CHO), the 2-cell stage embryos of mouse and rabbit, have been carried out by using XJX-2 ruby laser microbeam system. On the basis of using either naturel chromophore or vital staining, the effective and selective destructions in living cells of plants and animals tested were produced successfully.

The theories of atmospheric scintillation and its effects on laser engineering are combined and the dependence of loss factor on zenith distance are obtained. It has been proved that there exists a critical zenith below which the laser engineering can’t operate in accordance with the performance index predetermined without turbulence. From the model of the turbulent intensity distribution in Shanghai, we have calculated these characteristic quantities and got their values for two kinds of laser engineering. We investigated the scintillation characteristics of various wave shapes and their transformation, particularly the characteristics of laser beam wave and the problem of inclined path (for nonhomogeneous turbulence).

Laser experiments on three types of glasses doped with CdS,CdSe, PbSe;In2Te3 semiconductor compounds have been made. We observed nonlinear optical absorption effects of transmissivity varying with laser intensity at different laser wavelengths. When the glass samples were placed in the cavity, modulation effects of laser pulse were also observed.

The technique and experiments of ultra-violet preionization in molecular N2 laser and He-N2 laser are described briefly. The experimental results showed a significant improvement in the homogeneity of laser discharge. With UV preionization, the output of atmospheric He-N2 laser has been increased by four times and an increase of 30 torrs of the optimum working pressure of molecular N2 laser is obtained.

Experimental techniques of making white light reconstructed holograms are described. The maximum diffraction efficiency of the transmission hologram is about 84%.White light reconstructed holograms of 170×220mm2 are made. The reconstructed image can be observed simply by using a common table lamp, and the image is very bright and sharp.