Strategies for the characterization of partially coherent ultrashort pulses with dispersion scan

Established characterization methods for repetitive pulse trains tend to fail in the presence of degraded coherence properties. Partial coherence is present in several pulse generation schemes but is not yet properly addressed in many pulse characterization techniques. Full coherence is a common assumption in most techniques, and failing to detect and account for it can lead to erroneous measurements that can be easily overlooked. While some techniques can indicate the presence of a coherence degradation, no method is known that can simultaneously retrieve the enveloping pulse width as well as the coherence time within a pulse train. Here we propose different pertinent strategies to deal with partially coherent ultrashort pulses measured using dispersion scan. The effect of partial coherence in dispersion scan is first investigated, and the three strategies, namely fidelity measurement, mixed-states reconstruction, and self-calibrating dispersion scan, are subsequently demonstrated and compared. The demonstrated retrieval algorithms can be readily adapted to existing dispersion scan hardware. Therefore, this study leads the way toward a more holistic approach to pulse characterization, dealing with fewer assumptions on the pulse trains and resulting in more accurate measurements. (C) 2019 Optical Society of America