Phase stabilization of mode-locked lasers

We present results on carrier-envelope phase stabilization of mode-locked lasers. The carrier-envelope phase of femtosecond optical pulses becomes important when they are used to probe attosecond physics. We demonstrate that long-term carrier-envelope phase stability is possible to achieve. Using phase-stable lasers it is possible to combine the output of different lasers phase coherently. It is also possible to load them phase coherently into a cavity, yielding the prospect of high-intensity experiments without an amplifier. Finally, we present quantum interference control of injected currents in semiconductors, which provides a solid-state phase detector of the carrier-envelope phase.