This paper reports results of Tin doped fibre pumped by a semiconductor laser diode as an optical source for methane gas detection. The spectral characteristics of the Tm doped fibre pumped by the 788 nm laser diode is studied experimently and the fibre source is used in a correlation spectroscopy measurement system. With a short measurement cavity of 5.7 cm in length, a system noise level limited minimum detectable gas concentration of 0.47% is obtained. This value is far below the lower explosion level (5%) of methane gas. Thus it demonstrated the feasibility of using Tm doped fibre as an optical source for methane gas measurement.

Based on colinear acoustooptic coupling, the phase velocity of surface acoustic wave propagating in proton-exchanged LiNbO3 waveguides is measured. This measuring method is very simple and an accuracy of 1×10-3 has been obtained. With a little modification it can also be applied to waveguides which are fabricated by other processes besides proton-exchange.

The study of Nd:YAG laser second harmonic, beam shaping transmitted through fibre is reported. It is indicated that the resulted 60° divergence angle output uniform light sheet can be used in the test of 0.6 and 1.2 m wind tunnels.

Based on the wave theory, every error source and its influence on the wave abrration are analyzed, and the corresponding tolerance limit is formulated. The micromeasure principle for submicron size spot is analyzed. A microscope system is set up, and the quality of a light spot is evaluated effectively by the system.

A method of increasing energy utilization coefficient (EUC)in recording three-slit rainbow holograms is presented. The EUC is raised by following way: the first-step hologram (H1) is reconstructed by three parallel linear beams instead of parallel light. The experiment shows that the EUC is raised 8 times than usual methods.

The image formulas of volume holographic system have been derived. The formulas are also suitable for the system which possesses a plane wave as a reference beam. The more exact calculation results can be obtained if these formulas are used in solving the image coordinate values of volume holographic system. The fomulas of the lateral, longitudinal and angular magnifications are given. The relations between the coordinate values of the object, image point, ratio of wavelengths μ and the image magnifications are proved in this papaer.

This paper discribed briefly features of pulsed YAG laser welding technology in production of CRT electron gun. The theoretical basis of laser welding of electron gun and the selection of processing parameters have been discussed.

The austenized transformation of carbon steels of 20, 45 and T10 as well as cast iron of HT200 has been investigated at some length with SEM analyses. We put stress upon studying the sites of austenitic nucleation and discussing the determination of transformation points, Acl and Ac3, of materials in laser heating. For Fe-C alloys, Ac1=A1 = 727 ℃, and for hypoeutectoid steels, Ac3=13603.9×(ln 0.22d/ξ-2v)-1.

The single frequency operation of a cw Ti:sapphire laser has been realized with an astimagition compensated ring cavity of four mirrors. A wideband optical diode was placed inside the cavity to force the tarvelling wave to travel unidirectionally. An intracavity complexed birefrigent filter and an etalon were used to tune wavelength, reduce linewidth and select the single longitudinal mode. Laser frequency was locked to a confocal reference cavity through electronic servo loop. Less than 430 kHz of frequency fluctuation when output was 183 mW and less than 610 kHz of frequency fluctuation when output was 423 mW within one minute were demonstrated at the wavelength of 790 nm.

A 1.3 μm YAG pulsed laser is set up and its characteristics is analysed. The considerations of the choices of the optimum transmission of output mirror and choice of model of cavity are described and compared with those of the 1.06 μm YAG pulsed laser. The optimum transmission, and the relation between output energy of the YAG pulsed laser and transmission of output mirror at 1.32 μm and 1.34 μm are given.

In this paper we present some experimental results for a self-mode-locked Ti:Al2O3 laser, which was designed and set up using Ti:sapphire grown in our institute and all apparatus made in China. A stable laser pulse train with pulse duration of 53 fs, bandwidth of 13 nm, average power of 200 mW, and a tuning range of 750～850 nm have been obtained.

According to the experimental and theoretical results, it is found that there are two operation points in the non-exited area. When the output power exceeds a threshold, the operation point skips, resulting in a sudden- change of the output power of the CO2 laser.

Using the Stimulated Brillouin Back Scattering (SBBS) in high pressure CH4 gas as a phase conjugating mirror in a (Nd,Ce):YAG laser resonator, we have got 62.7 mJ near TEM00 mode laser pulses. Also, we have proposed a concept that SBS phase conjugating laser resonator is the result of many overlaped resonators of different lengths.

In this paper the Multichannel Quantum Deffect Theory (MQDT) has been applied to the calculation of the 2s-2p electron impact excitation cross sections and rate coefficients of Lithium like ions Al10+, Si11+ through the available spectral data of the Beryllium-like ions.The results are compared with Mewe'S values which are obtained by using interpolation formulae for the electron impact excitation of the Lithium-like ions. It is found that our calculated values agree within 5% with the Mewe's interpolation results.

In this paper, we have investigated the squeezing of light and atomic dipole squeezing in the J-C model with Kerr medium. We found that stuiable intensity Kerr effect will lead to increase the squeezing of light but with Kerr effect increase the atomic dipole squeezing will clearly reduce and finally almost to disappear.

A photoacoustic model for the solid phase chemical reaction was proposed. It was verified by simulation and the photoacoustic detection of two samples of the stainless steel and an amino-perchorate composite material, indicating that the model can well describe the photoacoustic effect of the solid chemical reaction excited by laser.