Two-level systems under the action of a laser pulse train are studied by rotating-wave approximation. By analytical and numerical calculations, stable region diagram of the energy state, wave functions and energy level shift are obtained.

For molecular gas lasers with two combined levels (including flowing type gas lasers), it is pointed out that if the short-range diffusion time is much shorter than the radiation lifetime spatial holes burned will be eliminated, and when the gas is rarefied, this condition becomes that the short-range free motion time should be much less than the radiation lifetime and more convenient criterions are given.

Birefringent filters used for tuning dye lasers are discribed. Aligning and installing methods and the results on laser tuning experiments are presented. Dependence of laser tuning on manufacturing tolerance is discussed.

Experimental study of UV-preionized KrCl excimer laser at 222 nm was performed. The dependence of the laser performances on its various parameters is discussed. Laser output energy of 60 mJ was extracted using He as diluent gas. KrCl radiative spectra are given. Laser line at 5461 A from Hg atoms was observed by photodissociation of HgI2 vapor with this excimer laser.

The recombination-type semi-insulating gallium arsenide material of high resistivity is prepared by B2O3 liquid encapsulated Czochralski method (LEC). The material is of lower absorption coefficient, higher infrared transmittance and good thermal stability. It has been proved that this material can fully meet the requirements for CW highpower CO3 laser windows.

Multiple-photon dissociation of CF3 CDC12-CF3 CHC12 gas mixtures in the field of a two frequency CO2 laser light is studied. The single-step deuterium isotopie enrichment factor attains a value of 1600. which is increased as compared to that for the single frequency case.

At present, stationary acousto-optic modulator is used for actively acousto-optic mode-locking of lasers. The operation state of modulator has its obvious influence on mode-locking and mode-locked pulses. This paper presents some experimental methods for discriminating the sound field states taking Baman-Nath modulator as an example.

In the design of transducers for bulk wave a-o devices, the thickness resonance frequency f0 is always taken as working frequency. By analysing and determining several characteristic frequencies for a transducer, it is pointed out that the mechanical resonance frequency f, must be taken as the working frequency, and a method for detemining tfs from the relationship graph on Smith chart between impedance and frequency of a transducer is proposed.

Thermal distortion of mirrors caused by high power CW laser radiation and pressure distortion by water-cooled back pressure have been measured using a Twyman-Green interferometer. Analysis of measurement results show that it is necessary to reduce the radiation power density and increase the diameter-thickness ratio of mirrors in order to minimize the thermal distortion by laser and pressure distortion. SiC is a good substrate material for laser mirrors with higher thermal conductivity, higher Young’s modules and lower coefficient of thermal expansion.

This paper disribes the unit technique of two-channel power supply with a repetition rate of 40 pps for solid state lasers. Operational amplifiers are used to improve the stability of discharging voltage. Constant-current prefired technique and SCR protector are adopted to assure laser power reliability.

In this paper we report the fanshaped superradiance of the dye laser achieved by using second harmonics from a giant pulsed YAP:Nd3+ laser oscillator-amplifier to pump Rhodamine 6G.

Experimental results of an unstable Nd:YAG resonator working at high-repetition-rate with confocal-positive-branch-construction are reported. Q-switched outputs of 158 mj in 7 ns have been obtained in a diffraction limited beam with a divergence of 0.33 mrad at 10 pps.

Superbroadening spectrum in H2O and CS2 by focused picosecond pulses at 5300 A is investigated.

Experimental results are given on the application of getter alloy ZrAl 16 in intracavity He-Ne lasers.

This paper presents the simple principle and method for detection of crack and plastic deformation on subsurface by photoacoustic effect. The hole and plastic deformation of subsurface in metal have been detected using our photoacoustic arragment.

Deformation of a clamped rectangular plate subjected to point force was measured by double exposure holographic interferometry. Experimental results are found to be close to the theoretical ones.

The matched filtering of computer-generated filters and three data processing methods for improving signal-to-noise ratio in optical information processing are described.

In our interference length measuring system the minimum display value attainable is 0.1 μm, with a measuring length of less than 4.8 metres. The necessary correction for laser wavelength in our system is affected by interpolation of value (1) in association with the changes of correction factor C3 (on the dial) according to testing conditions of temperature and pressure. The accuracy attainable is better than 1×10-7.

The influences of He-Ne laser illumination on blood flow rate over sacral region in a group of rabbits were observed using fluorescence angiography of bulbar conjunctival mic-rovessels in ear to eye circulation.Experimental results show that in normal rabbits, the circulation time after larger dosage irradiation with a density power of 3.54 MW/cm2 for 3 hours is significantly longer than that of the controlled group.The circulation time of the microcirculatory disturbance group after the same density power radiation for 24 minutes is significantly shorter than that of the controlled group.Through the change of blood flow rate, the machanism of He-Ne laser treatments on the adenexitis is discussed.