Study Of Laser-Induced Damage Threshold Test System

Laser films are an important part of optical systems,as the laser develops toward high energy and high power,it has higher requirements for laser damage resistance of optical films.Precise measurement of the laser-induced damage threshold(LIDT)is a prerequisite for the study of high-laser induced damage threshold film materials.For this reason,researchers have carried out a variety of the measurement methods for LIDT of optical films,but there are still has the deficiencies of low measurement accuracy and poor comparability.In this paper,in order to precise and efficient measurement of the LIDT,a measurement system for LIDT of optical films was designed to realize the intelligent,and automatic control of the test systemThe mechanism of laser induced optical film damage and the influence of laser parameters,film properties and film thickness on laser damage characteristics were analyzed theoretically.The measurement criteria,test methods and laser damage discrimination methods of laser damage threshold were discussedA fundamental transverse mode pulsed solid-state laser is designed for the laser source in the laser damage threshold test system.Considering the thermal lens effect of the laser crystal,the effects of the cavity length of the laser resonant cavity and the position of the laser crystal in the resonant cavity on the beam quality,pulse width and output energy of the output laser of the electro-optical Q-switched pulsed laser are studied.The flat-concave resonator was further optimized,and a stable 1064nm laser output was realized.The laser output mode was TEM00,the single pulse energy was 200mJ,and the pulse width was 13nsThe optical film laser-induced damage threshold test system was designed.In order to realize of the laser energy adjust continuously,the polarizer combine with half-wave plate laser energy attenuation device and the Glan-Taylor prism laser energy attenuation device were designed and studied respectively.The control precision of the laser energy of the two combined devices was compared.With its high extinction ratio and high laser resistance,the Glan-Taylor prism is more suitable for laser systems with high energy and high precision control requirements.The connection between the computer and various modules of the system is established through the single-chip microcomputer and RS422 serial port driver and realize the pulse control of lasers,and system control of attenuator,two dimensional translation stage,CCD camera are also realized.The laser damage threshold test system was debugged,and the damage threshold of the optical film was tested by the design laser-induced damage threshold system,using 1-on-1 measurement mode,the LIDT of 1 064 nm antireflection coating under the zero probability damage threshold is 1.67 J/cm2.