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The positive-branch confocal unstable resonator with inhomogeneous gain medium was studied for the normal used high energy DF laser system. The fast changing process of the resonator’s eigenmodes was coupled with the slow changing process of the thermal deformation of cavity mirrors. Influences of the thermal deformation of cavity mirrors to the outcoupled beam quality and transmission loss of high frequency components of high energy laser were computed. The simulations are done through programs compiled by MATLAB and GLAD software and the method of combination of finite elements and Fox-li iteration algorithm was used. Effects of thermal distortion, misaligned of cavity mirrors and inhomogeneous distribution of gain medium were introduced to simulate the real physical circumstances of laser cavity. The wavefront distribution and beam quality (including RMS of wavefront, power in the bucket, Strehl ratio, diffraction limit β, position of the beam spot center, spot size and intensity distribution in far-field ) of the distorted outcoupled beam were studied. The conclusions of the simulation agree with the experimental results. This work would supply references of wavefront correction range to the adaptive optics system of interior alleyway.

We simulate the integrated effects of atmospheric aberration, atmospheric turbulence, thermal blooming, random jitter of laser's intensity and phase, speed of wind, direction of wind, absorption of air, kinetic cooling of CO2 and N2, speed of target, output power and beam quality of laser, wavelength, focus length, and the launch altitude of laser to accurately simulate the transmission loss of the laser's energy, concentration of laser's power and other beam quality parameters of the laser propagating to the dynamic target. And we evaluate the efficiency of laser's irradiation on the target more accurately for the optical link of ground-to-airspace. We also investigate influences of characteristics of dynamic parameters (Strehl's ratio, RMS of wave-front, spatial distribution of intensity on the target, the real focus on the optical link and the peak intensity along the propagation path) including speed of wind, direction of wind, speed of target and the kinetic cooling effect of air, especially. We conclude that the higher speed of wind and target weakens the thermal blooming of atmosphere and improves the beam quality and efficiency of laser's irradiation on the target. The kinetic cooling effect of air is more remarkable to improve the beam quality irradiating on the target at the initial part of the propagation path of the laser. The changed direction of wind weakens the atmospheric aberration and directs to better beam quality and higher efficiency of laser's irradiation on the target.

The measuring system based on photon correlation spectroscopy is improved through several means. The distribution of nanometer particle's sizes measured by new systems is more stable and accurate. All of the experiments are done in an ultra-clean chamber. The temperature is controlled and changes from about 13 degrees centigrade to 22 degrees centigrade. Fibers with different core diameters are used to transmit scattering light. The "Y" type fibers with different core diameters are used to transmit both the incident laser and the scattering light. The microscope objectives with different numerical apertures are used to collect and couple the scattering light into fiber. The software of real time correlation is tried to be used in the measuring system and it is compared with the static correlation. The Labview is used to integrate the software of correlation and inverse algorithms of nanometer particle sizes. Influences of incident laser with different power and mode are analyzed.