From numerical calculation,the basic rules of saturated gain coefficient variation with the field distribution along the flow direction in a GDL cavity are presented.In connection with variations of vibrational energy and temperature of all modes,these rules are explained with the physical mechanism of relaxation of the active medium.It is pointed out that,for example,there still-exists considerable vibrational energy which can be used for Gerry’s device with 30 KW monomode output.

The frequency stabilizing property of two-frequency He-Ne laser depends upon the shape of the power tuning curve.The effects of mode competition and cross relaxation on the power tuning curve have been investigated bosh theoretically and experimentally.Moreover,in order to obtain the best frequency stabilizing property,the conditions for choosing optimum values of magnetic field and gas pressure are given.

The investigation of the phase conjugation properties of the stimulated Raman scattering backward-wave is reported.The results of the experiment indicated that the Stimulated Raman Scattering backward-wave is a phase conjugated wave of the pumping wave.In our experiment,the expected reproductive images of the pumping wave was obtained by using this phase conjugation.The conditions for generating the phase conjugation in Stimulated Raman Scattering backward-wave are discussed.

The stability Of the unstable cavity modes are discussed.It is proved that the converging wave in an approximate solution in geometric optics is not the stable mode from the cavity.The only stable solution is the diverging spherical wave.

Distribution of xenon lamp pumping energy in Nd glass rods have been caleulated with a low-speed computer.The calculation results are in basic agreement with the experimental ones.Some problems on improving pumping uniformity are discussed.

As Tonks-Langmuir lower pressure discharge plasma theory is compared with the operating condition of typical Ar~+ lasers,it is considered that this theory may be adaptive for the analysis of plasma parameters in Ar~+ lasers.It is believed that the two-step process plays an essential role in the excitation mechanism of CW Ar~+ lasers.Consequently,the dependenoe of the upper laser level population, which is in approximate proportion to laser output,on the filling-gas pressure in CW Ar~+ lasers is derived.The optimum pressure and electric temperature can then be determined.This result is in agreement with the experiment by H.Beorseh et al.The deviation between theoretical and experimental results in increasing pressure is explained.Some influential factors for determination of the optimum pressure are also discussed.

Single pulses at different time have been selected from a mode-locked pulse train produced in a passive mode-locked Nd:glass laser,and the temporal and spatial characteristics of the pulses have been studied.Experiments show that bandwidth-limited pulses with Gaussian temporal and spatial distribution appear in the front part of the pulse train,the spectral width is broadened significantly and obvious modulation appears with the evolution of the train.The broadening is in good agreement with theoretical calculation results.It proves that the broadening is caused by self phase modulation under the action of intense light.Some experimental phenomena are discussed.

Stark frequenoy shift for the CH3F optically pumped far infrared laser light has been theoertically calculated.It is pointed out that there is the possibility of resonance between the methylfluoride emmited far infrared laser line (496 μm) and 3P0→3P1 transition in Mg atomio beam at the electric field intensitry of 2.9×104～4.4×104 v/cm,meanwhile maintaining resonance between the laser levels of methylfluoride and the CO2 pumped line 9p(20).It has been predicted that there are four sets of possible operating transitions:QR(11,5,-11),QQ(12, 5,-11);QR(11,6,-6),QQ(12,6,-6);QR (11,7,-3),QQ (12,7,-3) and QR(11,8,0),QQ(12,8,0).

A Nd:YAG laser with diffraction limited output is reported.Its pulse width is 6～7ns (FWHM),spectral width about 0.35(FWHM).Maximum output is 60 mj,polarization,98% repetition rate,lpps.The laser resonator is a plane-convex unstable cavity.

Constitutional parameters of the pulsed dye laser and properties of the pumping laser are given.Emphasis is put on the experimental research on its tunable range and the bandwidth narrowing with a diffraction grating and a Fabry-Perot etalon.Experimental results of the dye laser properties and their measurement methods are given.

A new type of focusing lens which can focus a laser beam into a line of any length and its possible applications are proposed.

Experimental researches on the stability of the point light source in the “three point method”and the factors affecting the transmission of light beam were carried out,and a 21m long experimental arrangement for laser alignment with an accuracy of ±0.6～0.8μm (or ±3～4×10-8) was developed.The tide change of an artificial fault was measured with the arrangement,the maximum change for level displacement in 24 hours for a small tide period is within 11μm.The potentia- lity for prediction of earthquake,measurement of dam deformation and adjust- ment of particle accelarators are analyzed,effects of generalized relativistic temporal-spatial bending on aligning light beam are discussed.