Automated test station for laser-induced damage threshold measurements according to ISO 11254-2 standard

摘要

All laser components can withstand a limited intensity of optical radiation and the measurement of laser-induced damage thresholds (LIDT) is required. In the case of repetitive pulses the LIDT measurements should be performed according ISO 11254-2 standard. This procedure is time consuming and puts a high requirement on human resources. In order to speed up the LIDT measurements with a minimal human resource we developed the automated station for LIDT measurements according ISO-11254-2 standard. In this paper we overview the main parts of this automated station and present the results of LIDT measurements with repetitive pulses. In order to control the LIDT measurements, software based on LabView programming package was created. The LIDT software controls experimental sample positioning in X and Y directions, laser pulse energy attenuation and shutter. It also automates damage detection and performs statistical analysis. The program recognizes damage by detecting scattered light from damaged surface. The input of sample and laser beam technical parameters is required to start the measurements. The minimal distance between test sites on the sample surface is calculated automatically, and the surface area is divided in to a hexagonal matrix. The program also chooses the laser pulse train energy for each test site. The program also allows fast damage inspection by translating the sample under the Nomarski microscope. After completion of measurement and damage inspection, the program automatically generates the measurement report.