TM structure of laser and its loss characteristics for small aperture coupling output are analysed, an easy way to determine the optimum coupling aperture of laser resonant cavity is put forward, and the experimental results are very fine.

A hybrid laser consists of two or more different laser devices or laser medias emitting at the same wavelength of stimulated radiation. These lasers have the main advantages owned by the respective lasers. Three types of hybrid laser developed by the authors are described, i. e., gas-solid laser, solid-excimer laser and lower-higher gas pressures lasers.

10.6 μm heterodyne frequency stabilization systems of two lasers with a NH2D Stark cell is presented. The frequency stability of this system is measured with Allen variance method and computer processing on time. The measuring results is that long-term and short-term frequency stability is better than 3×1010 and 1.57×10-9 when the sampling time is Is and 1ms respectively.

Based on behaviours of acoustic-optic modulation in the resonator, the output characteristics of intracavity acoustic-optic modulator (IAOM) with feedback device are analysed, and the multistability of IAOM with active medium is discussed. Furthermore, the relations between the output power and the variables are given.

A three-baaed steels (45, 40 Cr, 40 CrNiMo) is chromeplated and processed by a 1.5 kW CO2 laser beam and a meltchromizing layer is formed on one side of the chrome-steel interface of the steel. The effects of processing parameters, alloy contents on the structural morphology and the distribution of Cr-concentration are investigated.

A non-alloying, stable Ohmie contacts on Si/Pd/GaAs were obtained. A specific contact resistivity of 2.75×10-6Ω·cm2 on 6.7×1017cm-3 substrates can be achieved after Ar+ laser annealing. The thermal stability is satisfactory for those annealed at 410℃ for about 8 hours in flowing forming gas.

The beam characteristics of exeimer lasers are detected by using a two dimensional CCD array. The beam uniformity and the drift of the gravity center of the beam pattern are investigated for long term operation of exeimer lasers. The relationship between the beam characteristics and discharge stability are discussed.

A pulsed laser energy of-400mJ and an average power of 22 W have been obtained from a XeCl excimer laser with automatic UV preionization, the overall laser efficiency is-2%. It is indicated by both theoretical analyses and experimental measurements that the efficiency of C-C energy transfer has significant effect on the characteristics of excimer lasers.

In the UV preionized excimer laser, the output energy of KrF laser is generally greater than that of the XeCl laser. Whereas the output energy of KrF laser is smaller than that of the XeCl laser with x-ray preionization. This results are explained by parametric research and kinetic analysis of the laser.

An excimer laser with high output in effective volume is described and the key techniques for obtaining high output are studied.

An industrial 5 kW level transverse-flow CO2 laser has been developed with good beam quality. The laser features a unique preionization electrode structure and mode-selecting technique. Sealed-off CW operation for more than 10hrs can be obtained for each gas refilling with a power unstability of ±1.0% and a shelf life of one month. A welding depth of 3-4 mm at 2 meters per minute can be achieved for the automobile gears with a depth to width ratio of 2.5:1.

The selection of parameters for miniature TEA CO2 lasers is analysed and a miniature whole metallic-sealed-off ceramic TEA CO2 laser is developed. Its TEM00 output is >20mj, pulse width106 shots and the shelf life is more than 10 years.

A practical 5 kW level CW CO2 laser is described. The related technological parameters and features are discussed and the approaches to improve its performances are suggested.

The influence of water temperature in a cathode tube on the output power of transverse flow CO2 laser is investigated. It has been shown that the increasing temperature of the cathode is advantageous to improve the discharge uniformity and stability.

A transverse output optical system and gas dynamic window of small diameter orifices for a 6 kW level CO2 laser is described. It has the advantages of less leakage of lasing gas and higher efficiency to prevent air molecules from diffusing into the laser cavity, and much lower consumption of lasing gas. It can also improve the laser beam modes.

The "black center" in the laser light beam is analysed for copper vapor lasers with a bore smaller than 60mm and the construction and performances of a 45 W copper vapor laser are deseribed.

Theoretical and experimental study on the polarization modes are performed on copper vapour lasers. The properties of polarized pulsed light are explored and the results show that the average polarizability of pulsed light is decreased with the increase of output power within a certain power range, whereas it is increased with the shortening of. the cavity length, and increased with the increase loss ratio M. These results are verified experimentally, and an average polarizability of 97.6% has been obtained for the laser output.

Timing of a copper vapor laser oscillator-amplifier chain operating at high repetition rate requires keeping every amplifier in the optimum delay condition. This paper reports a practical automatic timing control, of which the delay control precision is about 1ns. The set-up is a photoelectrie feedback system consisting mainly of photoelectric coupling fibers and a computer, providing with antijamming ability from high frequency electromagnetic waves.

We have quantitatively measured the far-field distribution of laser beams and the evolution of the copper vapor laser oscillator with telescopic resonator as well as the influences of the delay between the oscillator and the amplifier on the far-field pattern we explained with geometric theory of laser cavity the formation process of the far-field distribution.

A slab laser is reported for the amplication of ultrashort pulses. The gain of the Nd: YAG slab amplifier is greater than 29dB. The output energy of a single pulse at 1.064 μm is more than 200mj at 1-10Hz. Th:s amplifier has three output harmonic waves.

The pulsed laser performances of a-axis YAP crystal doped with 10at%, 20at% Er3+ ion have been studied experimentally. In our experimental condition, it is possible to excite simultaneously three spectral lines at 2.7110μm, 2.7299μm and 2.7950μm. The output energy and the time characteristics are given for these spectral lines. 240mJ output energy has been obtained at 2.7μm range from a 6.25×78mm Er3+:YAP rod with a threshold energy of about 10 J.

Pulse laser action of a-axis YAP crystal with an activator concentration of 1 at% Er3+ ion has been studied. Two spectral lines at 1.655μm and 1.6623μm can oscillate simultaneously in this laser. Both spectral lines are linear polarization beams with polarized directions parallel to erystallographie B and C axes respectively. The output energy curve and time habit of oscillation for both emissions are also given. 103.7mJ output energy at 1.66μm has beea achieved from φ5×75mm Er3+:YAP rod with a laser threshold of 28J.

The design and characteristics of a Nd: Phosphate glass slab laser operating at 16 joules per pulae and 4 pulses per second is reported.

The single pulse, high repetition rate and CW laser operation of NdAl3(BO3)4 crystal pumped with xenon and krypton flashlamps were studied and the high pulse repetition laser output from a NAB crystal pumped with flashlamps was obtained for the first time.

Theoretical analysis for the threshold, waveguide and lateral mode characteristics of InGaAsP/InP BC lasers is made by a numerical solution of the equations describing the steady state characteristics of graded waveguide semiconductor lasers. The calculating results show that a good fundamental transverse mode characteristics and stable optical field distribution can be easily obtained with BC lasers, which is in agreement with experimental results.

Optical pulses with a repetition frequency of 1GHz and pulse width of 17 ps at 1.3μm are obtained by using a comb generator and direct modulation of DCPBH lasers. Experiments on SHG correlation measurement system are also described. The depencence of pulse width and the peak power on the variation of biased current are shown, which indicates when the laser diode is biased near the threshold, the shortest pulse width and the highest peak can be obtained.

850nm GaAlAs/GaAs multiple quantum well lasers are prepared by a domestic molecular beam epitaxy system.The lasers have threshold current density of 980 A/cm2 at room temperarure, The lasers stripe width of 8um, the lowest room temperature threshold current is 28 mA, a linear power output of 15mW, a differential quantum efficiency per facet of about 24%, and a weak temperature dependence of threshold current density (T0-361℃ in the range of -35℃ to +30℃) are achieved.

A novel semieondnetor laser amplifier called semi-travelling-wave amplifier is proposed and the experimental results are given. This amplifier can be an optical filter while used as an optical gain device or an optical switch.

Using a compound method of scattering matrix and two-step equivalent reflectivity, the authors analyse the mechanism of single mode operation of coupled-cavity lasers for two cases, strong coupling and weak coupling and present the results of numerical analysis and the related conclusion.

A new configuration of negative electrical feedback linewidth narrowed semiconductor laser using optical fiber ring resonator as frequncy discriminator is presented. This scheme has been proved with 1.3℃m GRINROD external coupled cavity (GRECC) semiconductor laser as light source. The narrowest lin width output of the laser is 850kHz.

Au all-fiber amplifier, is made with monomode fiber couplers and Er3+/Yb3+-doped monomode optical fiber. For a 8 meter long Er3+/Yb3+ -doped fiber pumped by an argon laser beam (514.5nm), a small signal gain of 0.2ldB/mW at 1537nm is obtained.

Nd:YAG single crystal fiber is grown up by LHPG method and a LD-pumped monolithic Nd:YAG single crystal fiber laser is developed with an output power of>2mW and a slope efficiency of 5.3%.

Basod on experimental study of Nd-doped single-mode fiber lasers, we use the fundamental wode Gan-sian function to approximate signal light field and pumping light field distribution, and to obtain analytical expressions for the threshold power and slopeefficicney. Our calculation results agree well with the experimental ones.

The siable zone and waist size of an eight mirror long ring cavity with optical delay system in a colliding pulse mode-locked (CPM) dye laser is first calculated and analysed. The optimal largo radius of curvature for various cavity length and the dependence of the stable zone of cavity and the beam waist size on the large radius of curvature for a fixed cavity length are obtained.

Wavelength shift of CW ring dye lasers are analysed by means of rate equation model, the relationship between the intracavity and the output wavelength is given and the factors which have effects on the wavelength shift are discussed in detail. The theoretical analysis is essentially in agreement with the experimental results.

Very high efficiency and stable single frequency (SF) operation was obtained by using model 801D ring dye laser at normal pumping level. For 3.56 W Ar+ laser (blue-green) pumping, 748mW(R6G peak) SP output was obtained with an efficiency of 21%. By changing R110 and DCM dye, a tuning range of 530-670nm can be covered.

The optomechanical coefficient (Kf) of laser materials can be calculated by making 1n(1/f)-1n(Pin) diagrams and Kf=4.29×10-4m-1kW-1 have been obtained in Nd: YAP crystals.

The doped colour center Nd: YAG crystal can be used as an active medium or a passive modulator. The passive Q-switching pulse width is equal to or greater than 7 ns, the active and passive mode-locking pulse width is equal to or greater than 270 ps. When the pulse repetition rate is within 1-10 kHz, the pulse duration is equal to or greater than 200 ns. Nanosecond or subnanosecond active and passive mode-looking pulse durations are obtained and the frequency-doubling average output power is about 300 mW.

Cadmium tungstate single crystals doped with Cr3+ are grown by Czochralskrtechnique. The absorption spectra are measured. The low peaks of Cr3+ are due to the selfabsorption induced by the colour centers and the impurities. The positions of the major energylevels 4T1, 4T2 and 2E of Cr3+ and the energy level difference E=-1430cm-1 between 2E and4T2 are determined.

A novel nonlinear frequency-doubling material of organometallic complex -tri-allythiourea cadmium chloride (ATCC for short) is reported for the first time, which is explored by using powder screening method according to the "double-radical structure model". Comprehensive study is carried out on the linear and nonlinear optical properties of the ATCC crystal, and the efficient nonlinear coefficients have been obtained.

The oscillator strength,Ωx parameters, radiation transition probability and fluorescence branching ratio of Er3+ in Er3x3+:Y3-3xAl5O12 and Erx3+Yb1-xP5O14 crystals by using Judd-Of elt method are reported and some variation regularity of these parameters have been observed.

The dependence of the output power and the spectral pattern of a semiconductor laser diode biased below the threshold on the reflectivity of the diode facet has been studied theoretically and experimentally. This dependence has provided the basis for actively monitoring the antireflection coating on the diode. Preparation of AR coating on the diode facet and the measurement of the diode parameters have verified the theoretical prediction.

A scanning photothermal microscopy based on photothermal deflection spectroscopy is used to measure the absorption distribution of laser damaged films. Its detecting sensitivity and detecting accuracy is 2.5×10-6 and 18% respectively.

Experimental results on amorphous silicon growth by CO2 laser chemical vapor deposition are reported. Experimental results show that the deposition rate of silicon film strongly depends on silane pressure and substrate temperature. The samples are detected by different methods and the film amorphoasncss are verified with good photoconductivity.

Laser damage characteristics of film polarizers are reported and the relationship between the damage thresholds, fllm-desiga structures and overcoats are investigated.