Two-photon resonant four-wave mixing difference frequency generation in potassium vapor has been observed.The infrared wave (ω3) from YAG:Nd3+ laser and the visible wave(ω1) from the tunable dye laser pumped by the second-harmonic of YAG:Nd3+ laser are used as the incident waves.When the energy of the two photons from dye laser equals to the energy defferenco between the high lying state 13s and the ground stare 4s of the potassium atom,a new 4052 coherent wave (ω4=ω1-ω3) is generated.

This work deals with the oalculations on complicated Zeeman splittings of the 3S2→2P4 transition in Ne atoms and also with analysis on the conditions for pro- ducing Lamb dip for ]eft- and right handed circular polarized light.

An experimental study was conducted of the active mode-locking laser utilizing a l meter long photopreionized TEA CO2 device.A Brewster angle aceustooptic loss modulator was employed as the active mode locker within the cavity.Design consideration on experimental apparatus and the measured resuls are described.

The pumping model for an electron-beam controlled dischaging laser is described.A cold-cathode electron beam controlled dischaging CO2 laser system with 8 litres of excitation volume was designed on the basis of this model,and its operation eharacteristics are in agreement with the predicted ones.

Calculation of relation between the negative absorption coefficient a and the direction of the singular axes P.Q.has been made quantitatively for lasing condi- tions in Nd:YAP crystal for the first time,and this calculation is based on the complex Fresnel’s equation of the wave normals of light propagation in anisotropic medium.It is discussed by using this nature of singular axes that a circularly polarized laser beam output can be obtained.

An investigation was made of the formation of ultrashort pulse trains in an YAG laser,and the effects on the passive mode locking process of the initial dye absorption coefficient x_o,the saturable power of the dye solution I_s,and the ratio of the beam cross section in the laser medium to the beam cross section in the absorber.The laser under investigation produces bandwidth-limited output pulses at 1.06μm,with spectral profile and temporal profile in Gaussian function.Single pulses can be adjusted from 20ps to 200ps.

A simple method of double layer preionization was employed in a N2 laser (with four electrodes)excited by a double plate condenser Blumlein system,the output stability has been improved and output power increased.

Some methods and experimental results for increasing the output power of a 3250 He-Cd laser are presented,monomode output power of about 15m W has been obtained with a 95cm long discharging capillary.It is shown that laser output power can be increased by adding a small quantity of iodine vapor into the He-Cd+ positive column.

A method is described which produces a spatial filter with high efficiency and broad dynamical range by using composite hologram and bleaohing technique.The method was used in processing the defocus blurred images and good results have been obtained.