The coherent artifact in modern pulse measurements

All optical pulse cmeasurement techniques necessarily fail in multi-shot measurements of unstable pulse trains because the measurement can only provide a single result, despite of the presence of many different pulse shapes. At the very least, however, the technique should provide a reasonable estimate of a typical pulse in the train and indicate the train´s stability. While frequency-resolved optical gating (FROG, [1]) and spectral phase interferometry for direct electric-field reconstruction (SPIDER, [2]) naturally operate single-shot, multi-shot variants are very common, so it is important to understand the effects of instability on multi-shot measurements.