Abstract

Carrier-envelope phase (CEP) stabilization has proven an indispensable tool for frequency metrology and attosecond spectroscopy. CEP stabilization mostly relies on two types of lasers systems, namely the Ti:sapphire laser and mode-locked fiber lasers. In contrast, many other systems like thin-disk lasers have been found problematic for CEP stabilization. While it appears clear that a large range of physical parameters may influence the CEP, in particular on long time scales, all mechanical and technical noise sources are expected to have vanishing influence beyond the acoustic range. Moreover, it is expected that the noise dynamics are ruled by quantum noise in this range. Being caused by amplified spontaneous emission, quantum fluctuations in both the pump and the pumped laser affect pulse energy, timing, and center frequency of the mode-locked laser, which leads to nearly white CEP frequency noise for a free-running oscillator. Here we experimentally check this hypothesis by nonlinear time series analysis. While we find that two different fiber lasers show in fact the expected stochastic behaviour, we see significant traces of deterministic dynamics in the analysis of the Ti:sapphire laser data.

© 2015 IEEE