In the ICF high power laser drivers, a cemented doublet lens laser expanding system and reflectional expanding system for multi wave length are given.

A simply method to measure the thermal focal length of LD end pumped solid state lasers with stable resonators was presented. By scanning the slit across the field with expression of multi mode Gaussian distribution behind the output mirror of lasers, the radius and the M 2 factor describing the quality of beam were measured. The waist of the multi mode field and the TEM 00 mode at the same parameters of lasers could be deduced according to the law of multi mode Gassian beam propagation. Based on the standard matrix theory of stable resonator, the thermal focus length of the active medium was easily obtained. The thermal focal length of a LD end pumped Nd∶YVO 4 laser was measured and the experimental results were agreed with the prediction of the theory.

Based on the transmission matrix equations of Gausian beams and the divergent angle measurement of beam at far field, a method for indirectly measuring the thermal focal length of laser crystal is presented. The measurement precision of thermal lens up to 10% was achieved. The achieved measurement method is flexible, simple and convenient with higher precision, especially suits to LD pumped all solid state lasers.

The output of a high power pulsed CO 2 laser has been produced from a transverse flow CO 2 laser which has particular electrode structure and using the preionized pulse train switched technique. The measurement on the voltage wave, current wave and light wave has been introduced in detail, during from preionization to main discharge and finally, to laser output, and the results of the waves have been analyzed in brief. Moreover, a way of light measurement has been put forward by means of attenuating the light which is based on the light polarization feature.

A simple and practical fiber grating sensor for strain and temperature measurement is presented in this paper. By using prestrain technique, two Bragg wavelengths were created by one fiber Bragg grating, and the cross sensing effect was eliminated. Linear responds to strain and temperature were achieved in the measurable ranges.

A kind of three directional grating called grating rosette is made, and a new method for measuring residual stresses has been developed by means of the grating rosette and moire interference technique.

Based on the theory of light beam transmitting in the seawater and the principle light scattering by particles, underwater target reflection power of collimated green blue laser beam and the relation between water quality parameter and the backward scattering power were studied for monitoring the underwater target and water quality parameter in real time.

A sinusoidal phase modulating laser diode interferometer is proposed. It is used to measure micro vibration of an object in real time. The real time phase detector is constructed with a simple circuits. The amplitude and frequency of the vibrations are measured by synchronously detecting the phases in interference signal. The theoretical analysis and experimental results are given.

This paper introduces the method that has been used to accurately control eight beam energies of SHENGUANG Ⅱ system by a half-wave plate computer automatic controlling system and gives the balance controlling result.

Ghost reflections are a major consideration in the optical design of SG Ⅱ system. Here the ghost reflections of the main laser amplifier department are analyzed and calculated. The methods to avoid the ghost damages are introduced.

The lasing modes and the spanteneous emission factors of microdisk lasers are simply analysized in this paper. InGaAs/InGaAsP multiple quantum wells (MQWs) microdisk lasers are fabricated by using the methods of active ion etching (RIE) and selective chemical etching. The diameter of the microdisk lasers was 3 μm. InGaAs/InGaAsP MQWs microdisk lasers cooled by liquid nitrogen was optically pumped. The single mode lasing at 1.506 μm wavelength with threshold pump power about 18 μW is obtained.

By using the SBS PCM, a double way amplified beam with improved beam quality was obtained. The obtained laser frequency is 10 Hz, SBS reflectivity is 70%, and the amplifying coefficient of back SBS is 2.5, as well as a stable output with symmetric distribution was got.

The non critical phase matching KTP optical parametric oscillator (OPO), pumped by dual cell stimulated Brillouin scattering (SBS) pulse width tunable laser system, has achieved tunable pulse width and comparatively high transforming efficiency with low power pumping laser of ranging from less than 1 ns to 6 ns. The output character of this OPO is also analyzed along with experiment results according to characteristics of long pulse pumped OPO.

The beam quality factor of parametric light from KTP optical parametric oscillator pumped by a doubling frequency Nd∶YAG laser (532 nm) was measured by means of laser beam analyzer. The beam quality dependence of different pumping conditions is discussed such as pump power, pump beam diameter, OPO cavity length, phase matching mode, and pumping with or without reflection. In the theoretical analysis, double refractive walk off term is introduced into coupling wave equations which are numerically solved with light propagation method and Rungue Kutta algorithm. The molding results agree well with the observed OPO performance.

On the basis of the Fresnel diffraction theory and Collins formula, the transfer of Auto Correlation Function (ACF) of an arbitrary spatial wave front is studied. The transfer formula of ACF is given. And the analysis for some special optical systems is also concerned.

A simple model to describe the electron energy distribution in plasma produced by linely polarized optical field induced ionization is constructed on the basis of quasiclassical above threshold ionization theory and quasi static tunneling ionization theory. Resolved function expression is deduced which is simple and comprehended. The curve of B like N system is calculated. At the same time, the result is analyzed and the applied area is given.

Based on the maximum shear stress theory, a theoretical model is developed for the spallation of a plated film under irradiation of a short pulsed laser beam. The formula of the laser energy threshold for the plated film spallation and the relationship between the radius of the spallation zone and the parameters of both the laser beam and the plated film are deduced. As an example, the spallation of a ZrO 2 plated film irradiated by a ns degree short pulsed laser beam is calculated, and both the curve of the spallation radius vs. laser energy and the temperature data are obtained. The theoretical and experimental results are in good accordance with each other, which indicates that the theoretical model is reasonable. The theoretical model with its results declares that the axial rapid thermal expansion, the thermal softening of the film material and the cone shaped shearing sliding induced by both the shearing stress on the lateral cross section and the radial and circumferential stresses are the main causes of the spallation phenomenon.

The simulation on alignment and misalignment of a positive branch confocal resonator is described in the paper. The stability of laser beam influenced by the misalignment are elementally diagnosed by the aid of this simulation. The results of the simulation is accordant with the experiment and that the former is of better flexibility and intuition.

The properties of two photon induced fluorescence and up conversion lasing of three novel laser dyes, PSPI, DEASPI and HEASPI, have been experimentally investigated. The above dyes emitted strong two photon induced fluorescence centred at ～640 nm and up conversion lasing at ～620 nm when pumped with 1064 nm mode locked Nd∶YAG laser. The output/input characteristics of the up conversion lasing were measured, and a high up conversion lasing efficiency of 10.7 for DEASPI, 9.8% for PSPI, and 7.1% for HEASPI have been obtained.

This paper reported phase jumps in the process of Stimulated Brillouin Scattering. The jumped probability with the incident energy was measured. The result showed that the jumped probability in the medium CCl 4 is about 20%. Even if the incident energy is saturated, phase jumps still exist. Phase jumps disrupt the phase of the Stokes beam generated by SBS, therefore tend to decrease the coherence length, increase the spectral width of the Stokes signal, suspend the phase conjugation process and decrease the fidelity of phase conjugation.

The whole nonlinear optical coefficients of YCOB crystal are evaluated by PM SHG method and Maker Fringe method. The spatial distribution of d eff  is given. The d eff  reaches the maximum, 1.73 pm/V, at the direction (67°,143 5°). The SHG efficiency reaches 41.5% with a 5 mm long YCOB crystal cut along this direction.

The nonlinear optical characteristics in asymmetric coupled Zn 1-x Cd xSe/ZnSe quantum wells have been investigated by using the reflective second harmonic generation (SHG) measurement technique. It is found that the SHG signal is enhanced in the interwell coupling, and the SHG intensity decreases with increasing x. The dependence of the SHG intensity (p in /p out, p in /s out) in the asymmetric coupled quantum wells on the incident polarization angle is also observed.

A series of solid solution crystals: Gd x Y 1-x Ca 4O(BO 3) 3 (x=0～0.4) were grown by Czochralski method and their critical phase matching angles of third harmonic generation (THG) of Nd∶YAG laser (1064 nm) were measured. The non critical phase matching (NCPM) of THG can be realized in Gd 0.37 Y 0.63 Ca 4O(BO 3)3 (GYCOB) crystal along the principal Y axis. The THG experiments of the Y cut GYCOB crystal with the length of 11 mm was performed using Q switched Nd∶YAG laser and the conversion efficiency of the crystal from 1064 nm to 355 nm was 14.7%.

The mode coupling characteristic in the asymmetrical coupler is studied theoretically and experimntally. The cirtical fiber mismatch criterion of r2/r1=0.62～0.63 is given. It is shown that when the fiber mismatch exceeds the limit, higher order mode coupling occurs and the splitting ratio decreases. By controlling the fiber mismatch properly, the fiber null coupler with splitting ratio of 5×10 3～10 5 and loss of 0.1～0.2 dB is made.

An anti reflection film coated on the sapphire window is made. By comparing the sapphire window with quartz window, it is found that the sapphire is a very promising window material for high power laser.