In this paper, an energy model of FEL was set up to calculate the energy tranfer rate of FEL under the conditions of small signal and strong signal respectively. This model was simple in calculating, clear in physical meaning and adequate for FEL with different magnetic structures, such as FEL uwith wigglers, FEL with axial magnetic field FEL with helical axial magnetic field combination. It could be used to deal with various problems such as harmonc radiation, short wavelength radiation, parameter variations and so on. The model is suitable for three dimensional problems.

A single frequency high output power He-Ne laser was obtained with Inhomo-geneous longitudinal magnetic field and high gas pressure, it has high frequency stability and a coherence length of greater than 14 meters. This paper presents the theoretical analysis on the operation mechanism.

The working state of Free-electron lasers with travelling wave radiation field wiggler is analysed, the laser gain is calculated and the conditions for obtaining gains are also analysed.

A light-activated GaAs/GaAlAs heterostructure negative resistance laser has been made by horizontal liquid-phase epitaxial growth. The operation principle and some of the characteristics of the device are described.

Continuously tunable laser output at 60.4 nm in the range of 735.7 nm to 796.1 nm has been obtained in an alexandrite laser with a three-element quartz birefringent filter. The laser linewidth is about 0.001 nm when a LiF crystal as passive Q-switch is used for single pulse operation. The output energy does not decrease obviously while the oscillating threshold increases by only 5%.

The paper reports the study of synchronous mode-looking of dye laser which hag a hemispherical resonator with a diffraction grating of E = 2M radius of curvature and is pumped by the second-harmonic pulse train from an actively passively mode-locked repetitive pulsed Nd: YAG laser. A broadly tunable, high-power mode-locked dye laser source has been achieved. Beal-time experimental investigation was made of some relationship governing the output characteristics of the dye laser with a BWS-5K high resolution streak camera. Brief analysis and discussion are given concerning the experimental results.

Frequency-doubled light from a repetitive pulse and mode-locked YAG laser of thermally stable cavity was used to synchronously pump a R-6G- dye laser. Experimentai results obtained are as follows: average power 14 mW, peak power of single pulse over 5 MW, single pulse width 28 ps, repetition rate of pulse train 20 pps, tunable range from 555. 0 nm to 586. 5 nm, spectral linewidth 0.1 nm, conversion efficiency 11%; when the linewidth is 0.04nm, the conversion efficiency is 8%.

The electrical pulse sharpening effect in ferrite transmission lines and the dependence of transmission speed of voltage wavefront on the bias magnetization current have been observed in detail.Combining two sharpened pulses with different sign and a certain relative delay time ns, 8kV pulse with continously variable width have been obtained. A Pockels cell was driven by the pulse to slice Q-switched laser pulses.

Possibility of producing image-plane holograms of astigmatic system is analyzed theoretically, and verified experimentally. When the hologram fabricated by such technique is reconstructed with white light point source, a distortionless, white-black holographic image with certain depth is obtained.

The expresion for conversion efficiency of the stimulated Eaman scatteting pumped by a focusing laser beam is deduced in this paper, The effects of focusing parameters on the conversion efficiency are analyzed, the calculated result shows that the optimum focusing parameters were related to the pumping power intensity. Our recent experimental results are in agreement with the above analyses.

Hyperfine spectrum of a ro-vibrational line of the iodine molecule at 629nm of He-22 Ne laser has been observed by a specific saturated-absorption spectroscopy.

A transversely-excited flow CO2 laser with an output power of about 2kW is used for cladding of metallic surfaces. Microstruotural analyses of treated surfaces indicate that laser cladding offers feasibility to apply high malting cladding] alloys on low melting workpieces to increase resistance to wear,erosion and corrosion, so. that it has the desired, high quality surface properties characteristic of high performance alloys.

The process of flux growth of KTiOPO4(KTP) crystals is briefly described. The larfgest crystal grown is 42.5×42.0× 13.6mm. With the devices made by KTP crystals in the Nd:YAG mode-locked laser, frequency-doubling conversion efficiency of the extracavity device obtained is 65.1%; while in quasie-CW Nd:YAG laser, the average green light output obtained is 8.7W.

The delay and jitter characteristics of the three electrode spark gap weres studied in this paper. A three stage Marx bank was designed using synchronous trigger pulses for each spark gap. Bise-time of output voltage of the Marx bank can be controlled within less than 100 ns with the jitter time of less than 10 ns.

Experiments show that methyl silieone oil coated on the face of phosphate laser glass rods can preven the surface from moisture without adverse effects on the laser efficiency and the damage threshold.

An electrically initiated chemical laser of SF6-H2-D2 mixture system is reported. The laser emission is in the range of 2.6-4 μm. The characteristics of spectral energy distribution were investigated by changing H2-D2mixture composition.