The investigation of the influence polarization orientation on damage performance of type I doubler KDP crystals grown by the conventional growth method under under 532nm pulse exposure is carried out in this work. The obtained results point out the pinpoint density (ppd) of polarization parallels the extraordinary axis is around 1.5× less than that of polarization parallels the ordinary axis under the same fluence, although polarization has no influence on size distribution of pinpoints. Meanwhile, crystal inhomogeneity is observed during experiment.
A multipurpose laser damage test facility delivering pulses from 1ns to 20ns and designed to output energy 40 Joule at 351nm is presented. The laser induced damage threshold (LIDT) measurement and test procedure are performed. The original system consist of the online detection system based on the microscopy and an energy detection device based on the scientific grade Charge Coupled Device (CCD) which provides the method to measure the LIDT with high accuracy. This method is an efficient way that allows measuring a small area fluence which the defect exposed. After complete test procedure and data treatment the damage position of the defect has been found. Then we can obtain the local fluence of small area when the damage occurred. This procedure provides a straightforward means of laser-damage threshold obtained from the test method. Damage correlation of measures is discussed in connection with present theoretical understanding of laser damage phenomenon. The damage process in transparent dielectric materials being the results of complex processes involving multi-photon ionization, avalanche ionization, electron-phonon coupling, and thermal effects. Those complex processes lead to the damage on the optical surface. We performed a method to measure the local fluence which defects irradiated with high accurate.
For researching the influence factors of the damage threshold test results, the 1 on 1 test program and data processing on fused SiO2 optical elements was numerically simulated with Monte Carlo method. The influence of the surface defect density and the target test spots area for the test results of damage threshold was studied. The numerical simulation results indicate that the damage threshold of optical elements can't be accurately evaluated with 1 on 1 test program if the surface defects have the characteristics of both low density and low damage threshold. The zero-probability damage threshold isn't equal to the minimum energy density when the laser induced damage of optical element appears. This work is helpful for understanding the 1 on 1 test result and has important reference value in the actual damage threshold test of optical elements using 1 on 1 test method.
In this paper, we investigated the effects of laser pulse width on laser-induced damage. We measured the damage threshold of K9 glass
and UBK7 glass optical components at different pulse width, then analysis pulse-width dependence of damage threshold. It is shown
that damage threshold at different pulse width conforms to thermal restriction mechanism, Because of cm size laser beam, defect on
the optical component surface leads to laser-induced threshold decreased.
In this paper, the measurement method of long focal length in a Fizeau interferometer with combination lenses is stated. According to the principle of geometry optics, two focal length calculation formulae are deduced for the measurement method. The optimization of measurement parameter values is analyzed, and the optimized values of measurement parameters are selected. By analyzing the measurement error of the focal length needed to be measured, the permitted error ranges of measurement parameters are obtained for the optimization of parameters so as to meet the requirement of measurement accuracy of focal length (±0.1%). By means of analysis, it is obtained that the measurement method can meet the requirement (±0.1%) of measurement accuracy of long focal length of high power laser Facility.
Proc. SPIE. 5627, High-Power Lasers and Applications III
KEYWORDS: Diffraction, Optical amplifiers, High power lasers, Solid state lasers, Laser beam propagation, Adaptive optics, Near field, Wave propagation, Beam propagation method, Laser systems engineering
The characteristics of linear propagation and amplification of pulse in the high-power solid-state laser system were analyzed. The decomposition of linear propagation of the different parts in this system was also made. And the controlling means for beam quantity were put forward. At the same time, the measured near field and far field of the beam in TIL (Technical integrated experiment line, the prototype of SGIII (the Laser facility for ICF in China) were discussed, which proved these means were valid. These results of the theoretical analysis and experiment research become the general idea for investigating the problem of linear propagation in this system.
In this paper, the physical models of the code SG99, which is used to simulate the pulse behavior in high power laser system, are presented in details. The experimental results are also presented to show that SG99 is capable of simulating pulse propagation well and yields reasonable results. In the last, some results in design of TIL(Technical Integrated Experiment Line), the prototype of ShenGuangIII, are also introduced.