Detection And Analysis Of High Power Laser Induced Damage By Image Segmentation Method

Nowdays, the high power laser has important applications in modern society. However,materials are inevitably damaged under the high power laser irradiation. the. Especially for theoptial componentsused in the high power laser system, the laser induced damage usually occur dueto the intense field in short time during the process of the ICF (Inertial Confinement Fusion). thisshould induce a worse laser beam quality, and further result in the unnormal fuction for the system.If optical components are more severly damaged, laser devices may don’t operate. For some sense,the power level and the performance of the laser system are limited by the damage resistance of thecomponents to intense laser illumination. However, the interaction of high power laser and opticalcomponents is affectted by lots of factors lying in physics or chemistry. and study the it is veryimportant for researchers and engineers to accurately determine the damage to study the damagedegree of the laser energy.This thesis includes the following research contents：1.An optic component’s damage threshold measurement platform base on ISO11254has beendesigned and built up by using the Energylite-20laser system.The equipments and methods used inthe whole process of measurement including the gain of laser spot’s size, splitting ratio, energydistribution and laser beam’s pulse width are introduced.2.A model for analyzing the image information of damage spots is studied based on thebackground difference method. By testing, dividing and locating the original images, exactmeasurement of damage spots is therefore carried out. The images of damage spots in two laseroperating mode, i.e. S-on-1and N-on-1are compared, and the growth of damage is analyzed. Thefunctions for evaluating the gray and area of damage are obtained.3.The theoretical data by using the functions and actual results of different damage types inquartz and fluoride phosphate glasses are compared and validated. The factors affecting the damagegrowth coefficient have been analyzed.4. A division method for laser beam quality is established based on the threshold segmentationprinciple and the area of energy are divided therefore. The energy distribution is analyzed andverified.