Test And Control System For Laser Induced Damage Threshold Of Optical Coating

Resistance damage capacity of optical coating brings seriously impact to the output of laser and the working life of optical components. Laser induced damage thresholds(LIDT) is an important index to evaluate the ability of optical coating on resisting damage from laser, and nowadays this accurate measurement has became particularly important. So, researchers develop many test ways of LIDT, there are still defection. The one hand, many human factors are involved from manual method operation, which leads to low measuring accuracy, the other hand, there are differences among the beam parameters and working way of laser, testing way, computational method of LIDT, test date do not agree and as the reference standard. So, studying automatic test system of LIDT is particularly important.In this paper, according to the international standard ISO11254 forming test equipment of LIDT, Online image detection technique as a method for damage identification method. The working principle of this technique is that observed the pixel change of testing site before and after laser shots by computer, when the pixel intensity values from two image is different we think the test site have been damaged. Instead of observing the change of samples with eye, the measurement accuracy is enhanced. Under the VB software developing the automatic test software that the control software of high energy laser, attenuator, intelligent damage detection system,2d control sample sets and so on, and operation interfaces of the upper machine control system (start, calibration, detection adjustment, set parameter, test) Setting up many controls in operation interfaces which the hardware devices needs in the test process, clicking the control to connect and automatic control the hard device. The communication of the hard devices and the control system is undertaken by MSComm. According to zero chance algorithms, we produce data processing software to get test data by online fitting curve. Visual operation interfaces is very convenient to handle for user.Have finished working contains design the operation interfaces, write program code, the operation interfaces easily handled and exchanged information for user, the communication and related parameters settings between the hardware devices and Industrial PC is finished by subroutine, running the control program to get automatic and intelligent test of LIDT. By analyzing the repeatability of test data is strong; the stability of the control system is good.