A key reason forstudying ultrafast processes on microscopic level is to understand the real-world.Ultrafast laser technologyhas been essential condition of studying ultrafast processes.Thepurpose, necessity, realization and results of application of ultrafast laser torepresentitive ultrafast processes of recent years are elaborated while new advances inthe research of ultrafast phenomena are introduced.

The theory of LDend-pumped solid-state lasers is analyzed, and a method that measures the effectivestimulated emission cross-section σe of laser crystal is ascertained. We compare the threshold andslope efficiency of four Nd:YVO₄crystals which have different doping levels,and calculate the σeof these crystals with upper-level life-times that have measured by us. Our results showthat the 1.9at% Nd:YVO₄crystal has a σeTe of 18.3 μscm²which is largest in all the four samples.

Nonadiabatic linewidthof a V-type noninversion laser is calculated on the basis of a c-number quantum Langevinapproach in lowest order of the laser field. It is shown that when the driving field isvery strong, the system behaves adiabatically whether with good or bad cavity.

In this paper, thelocations of KD*P crystal in a Q-switched tunable Cr:LiSAF laser are analyzed, and isproved that they are all available.

In this paper, thelinewidth factor of input light is introduced, and the spectrum density of active opticalfiber ring resonator filter and other correlated formulas are also proposed by usingmultiple light interference theory. Based on these formulas, it is convenient to optimizethe structure and parameters of active optical fiber ring resonator. When this activefilter is working in lock-in state, the stabilized and narrowed output light is produced.

Recently, interest hasbeen shown in YDFA. The reasons for this growth of interes include it's simple energylevel structure, no excited state absorption at either pump or signal wavelengths, noconcentration quenching, and it's broad spectrum both in absorption and emi:sion. In thispaper, the YDFA's which incorporates isolator, filter or fiber grating are investigatetheoretically, using a simple model. The optimum placement of the filters and isolatorsare als calculated so that the gain and noise performance can be improved simultaneously.

In this paper, thepolarization response of D-shaped side hole fiber is tested in experiment and calculatedin theory. It is found that the polarization ratio of output light is dependent onpolarization direction of its input light and polarity effect is obviously existed. Thiseffect is caused by the structure of D-shaped side hole by which the rotational symmetryof fiber is destroyed.The conclusion of theory is consistent with result of experiment .

Characteristic analysisof TE waves in nonlinear planar waveguides with Kerr-type core is analyzed by using Jacobielliptic function. Dispersion equation,formulas for dependence of field distributionoptical power on modal index are given. Errors in a published paper (Boardman andEgan,1986) are corrected. Correct data and curves are given for a typical example. Ourresultshave been carefully checked by methods of numerical analysis.

Based on MATLAB languageand finite element method,We proposed a novel method to analyze the electric field oftravelling-wave electrodes in design of integrated M-Z modulator.The result is verysatisfied and the running time of program is shortened 12 times.

The effects of atomicmotion and field mode structure on quantum statistics properties of the field in theJaynes-Cummings model are investigated.

The atomic quantumbehavior in the interaction system of a single-mode light field with the nonlinearJaynes-Cummings model via two-photon processes are studied by means of quantum theory. Thecondition for taking place of the phenomenon of coherent trapping is given.The influencesof the nonlinear correction term and the two-photon frequency detuning on the timeevolution of atomic particle number population inversion and the atomic dipole squeezingare discussed,respectively,when the initial field is on the vacuum state (= 0) and on the thermalchaotic state (≠ 0).

The superpositionstates,which are composed of q-vacuum state and q-coherent state,are presented,and theiramplitude-squared squeezing properties are disscused. The effects of the superpositioncoefficient and deformed parameter on their amplitude-squared squeezing properties arestudied with the aid of numerical calculation.

The atomic dipoleamplitude-squared squeezing of two two-level atoms with one-mode rediation field isstudied. The influences of the relative value of two atom-field coupling constants and thephoton multiple of transition on the squeezing effect is discussed. The relationship between atomic dipole amplitude-squared squeezing and field amplitude-squared squeezing arealso discussed.

Considering the effectof walk-off angle,the accurate calculation of effective nonlinear optical coefficient ofuniaxial crystal is presented,a example of calculation of BBO is given.

The Henonsynchronization of identical systems via active-passive decomposition (APD)have beenrealized. But the chaos synchronization by coninuously coupling is not easy. the Henonsynchronization of unidentical systems by active-occasional coupling have also beenrealized,when the synthronization phases exceed the critical value,the synchronizationHenon mapping via active-occasional copling will be obtained. The synchronization ofunidentical systems will make it potentially useful in secure communicaton.

This article covers theprinciple of an inverter using a magnetic flux control PWM algorithm and the implementingmethod by special MCU.

The dynamicalcharacteristics of the gas flow in Turbo-Disk LP-MOCVD chamber is analysed. The dynamicalpressure model of suppressing In desorption during InGaAlP epitaxial layer grown byLP-MOCVD at high growth temperature around 700 ℃ is presented. The effects of the growth parameters such asthe disk speed and the reaction pressure on In composition in InGaAlP epitaxial layers areexplained based on our model.

The four forms of beamexpander with a two-mirror system are compared in this paper.The conclusion has beengiven,which explains a beam expaader with two parabolic mirrors can eliminate sphericalaberration,coma and astigmatism at any ratio of shade or magnification,and therelationship between coefficient of distortion and ratio of shade is given too. Therelationship between coefficient of field curvature and ratio of shade are got throughlight traces. The different light rays are drawn apart when the ratio of shade is positiveor negative and so do their off-axis forms.

A meteorologicalparameter and atmospheric turbulence measurement system was described in this paper. A/Dconversion was done by VFC (Voltage Frequency Changer). The system has been implemented ata 27 m tower in Gaomeigu Yunnan Astronomical Observatory,that includes three levelsfast-response temperature sensors and two slow-response temperature sensors,a humiditysensor,a pressure sensor,a propeller-vane anemometer,Computer selects input channelsand pulse signal is counted by 8253 counter,so the system cost is low and the measuringprecision of long distance sampling signal can be ensured.

First,the applicationvalues,measurement fundamentals and process of the irradiance based method wereexpounded,when it was used in observation of atmospheric environment(OAE).Second,basedon the experiment study by using the VF921-256 spectrometer,some character isticparameters,such as aerosol spectral optical deepth,ozone column content,diffuse-to-global irradiance ratio and aerosol size distribution were retrieved,which arenecessary to OAE. Finally,some error sources which should be considered in OAE werediscussed.