The S-on-1 test is a multiple-shot technique that accounts for optics aging (fatigue).
Test procedure:
S-on-1 (also known as N-on-1) test is a destructive testing based on laser-induced damage statistics. The optical element's entrance surface is divided into test sites forming a virtual matrix. Each site within a fixed set is individually exposed to a burst of laser pulses at a constant peak fluence. A fluence is increasing incrementally for different sets of test samples. During irradiation sample is monitored for damage: if the damage is detected irradiation is stopped and the dose required to trigger damage is recorded. Otherwise, the test site is considered survived and a maximum number of S laser pulses is recorded. After exposure, the status of all test sites is inspected using offline DIC microscopy. Collected damage statistics are then used to calculate LIDT dependence versus the number of applied laser pulses (exposure dose).
For CW irradiation: the 1(Time)-on-1 procedure can be applied by varying exposure time instead of pulse number.
Learn more: ISO S-on-1 LIDT procedure