A transmission hologram can be reconstructed by both transmission and reflection. This paper presents the calculation and analysis on the principles and imaging positions of eight reconstructed images. The results are in good agreement with those obtained in experiments.

Mode-locked pulses generated by a tunable flashlamp-pumped dye laser was amplified in three stages of dye laser amplifiers pumped by the XeCl excimer laser, using another XeCl excimer laser to amplify the frequency-doubled pulses, picosecond high power laser pulses were obtained at 308 nm with a peak power of 500 MW, and the net power gain is 200.

F-P resonators with higher fineness can be used to select CO2 laser lines, while those with lower fineness can be used to extend the spectral range of a tunable CO2 laser and increase its output power. In this paper, operation performances of a tunable CO2 laser with a NaCl F-P window perpendicular to the axis of the tube are analysed.

The energy transfer characteristics of a flashlamp pumped dye laser in PTM operation is investigated according to the differential-integral equations derived from the rate equations. Principal differences between energy transfer processes in normal operation and PTM operation are compared. The dependences of energy transfer to stimulated emission, non-stimulated emission, the loss in the cavity and the absorption in the triplet etc on the photon life-times are given.

The energy exchange between relativistic electrons (r.e.) and light radiation are discussed on the basis of the movement equations for the interaction of relativistic electrons with periodic field and the radiation field. It is shown that effective energy exchange can take place only at the frequeney satisfying the resonance condition. Depending on their phase of light relation, radiation can be amplified by the relativistic electrons or becomes the force accelerating the electrons.

Experimental results on the lifetime of a sealed-off branch-selected CO laser operating at room temperature are reported. Some factors affecting the life-time are studied. Under some conditions, 104 lines were obtained and the strongest among them has an output power of 3.5 W. The divece has been operating continuously for more than 10000 hours.

The principles and functions of frequency shift are discussed. A LDV system using an acousto-optic modulator as its optical frequency shift device is presented. The measurements of the highly turbulent recirculating flow in a two-dimensional duct with a single step expansion were successfully performed by employing the LDV system.

Ethyl bromide or iodide at 20 torr was irradiated by a TEA CO2 laser. The reaction products were identified by means of infrared spectrometry, gas chromatography and CW CO2 laser photoacoustic spectroscopy. It has been proved that comparable amount of ethy-lene and acetylene are main products. It is reasonable to conclude that acetylene was produced directly from C2H5X via the simultaneous elimination of HX and H2 by laser irradiation and not brought by the subsequent photolysis of ethylene by the same laser.

This paper reports a new method using front-mirror leaked light for feedback control. It has no insertion loss and is able to track linearly. Preliminary results show that it can meet the needs of automatic light power control for present fiber communication systems.

Typical optogalvanic spectra of neon, lithium, sodium, calcium and nickel were obtained using hollow cathode lamps and a tunable CW dye laser in the 574-625 nm range. 43 spectral lines of neon were identified and the first optogalvanic spectroscopical data were provided for calibrating wavelengths. Optimum conditions for generating optogalvanic spectra and the characteristics of optogalvanic spectroscopy were discussed.

Experimental study on the mechanism of lowering breakdown voltage in He-Ne laser tubes of low breakdown voltage is described by using "simplified equivalent model tubes","potential probe method" and the means of contrast tests. On the basis of experiments, a new explanation of mechanism of lowering breakdown voltage is given.

This paper describes the design of general arrangement, resonant cavity, optical condenser, frequency doubler and cooling system of the BPJ-1 frequency doubled Nd:YAG laser. Laser parameters are as follows: pulse energy 0.3 j, pulse duration45%, the device can operate continuously for 30 minutes.

This paper mainly describes the laser hazards, threshold limit and safe operation rules for each of the following ten lasers: He-Ne, He-Cd, Kr+, Ar+, Nd: YAQ, Nd: glass, CO2, N2, ruby and dye lasers.

A method of measuring the non-linearity of PbS infrared detectors and the experimental set up are described. The results show that the nonlinearity is whithin 1% if the radiant flux is less than 0.1mW(at 0.83pm).

A method for the mesurement of loss, gain and saturation parameters of Ar+laser is proposed. The gain of weak signal and the saturation power as a function of current density at 4880A and 5145A are plotted, and the optimum values of transmissivity for these two lines are given.