Pass/Fail LIDT Certification Test using Raser Scan Exposure

Use this test for:

• Checking/certifying laser damage performance of the entire production batch;
• Check purchased optic’s quality before use in critical applications;
• Inspect whether optical element meets qualifications;
• Asses worst case scenario of LIDT of defect-driven damage;

Test description

To perform the Pass/Fail certification test procedure several test sites is often not enough in case of low defect density. In this case a large area is interrogated with a fixed laser irradiation level. In case all test area survives irradiation without damage sample is certified as good enough for further use. Otherwise, the component does not meet the specifications and cannot be used anyway.

Known limitations and risks:

• False-positive results are possible if there is a delayed fatigue effect (use also extended irradiation dose and endurance certification if possible);
• No exact information about the actual LIDT (just lower or higher than irradiation level of certification);

Most popular test parameters for this test

⁽¹⁾ effective pulse duration measured at Full Width Half Maximum

Why certifications are different?

There are various modifications of pass or fail testing. The reason behind such variety is mainly related with dominating failure mode (defect driven or fatigue driven), namely:

• “Classical” certification – covers only small area and short irradiation time, thus often might give false positive outcome for low defect density samples or large optics;
• “Single level raster-scan” certification – covers large test area, but has limited irradiation dose;
• “Endurance certification” – covers small area, but considers long term fatigue or laser-induced ageing effects;