The coherent artifact in interferometric pulse-measurement techniques

We study multi-shot intensity-and-phase measurements of unstable trains of ultrashort pulses using two-dimensional spectral shearing interferometry (2DSI) and self-referenced spectral interferometry (SRSI) in order to identify warning signs of pulse-shape instability.

1. Introduction

In multi-shot measurements of pulse trains with pulse-shape instabilities, all ultrashort-pulse-characterization techniques are doomed to fail. Because the measurement averages over different events and can provide only a single result, any such result must necessarily be incorrect. The best that can be expected is a reasonable representation of the typical pulse intensity and phase vs. time and an indication of the stability of the pulse train or other indication of the reliability of the measurement.