Abstract

Stabilization of the carrier-envelope (CE) phase of optical pulses can be achieved via two main approaches [1-3]. Feed-forward stabilization [3] is realized through shifting of the entire optical comb to zero CE offset frequency by an acousto-optic frequency shifter (AOFS) and has proven to be superior to feedback stabilization [1,2] in terms of effective servo bandwidth and demonstrated residual CE phase jitters down to 20 mrad. However, there are limitations of the feed-forward scheme [3]. First, a slow feed-back loop may still be needed to track slow fluctuations of the CE beatnote. Second, the acoustic propagation delay in the modulator crystal from the transducer to the interaction volume is usually >1μs, thus limiting the effective servo bandwidth to <400 kHz, which is still insufficient for extremely noisy lasers, e.g., certain fiber lasers. Here we experimentally demonstrate a novel approach for overcoming these adverse effects, enabling virtually unlimited servo bandwidths of several megahertz.

© 2015 IEEE