Long-term locking of the carrier-envelope phase in a 15-fs Ti:S laser using a self-referencing frequency domain technique

Summary form only given. Shortly after generation of optical pulses approached the few cycle regime, interest was sparked in locking the relative phase between the carrier frequency and the pulse amplitude envelope. In general the relative phase in successive pulses generated by mode-locked lasers is not constant due to a difference between the group and phase velocities inside the cavity. To date nearly all techniques of phase control of femtosecond (fs) pulses have utilized time domain methods. However, these techniques have not utilized active feedback and rapid dephasing occurs due pulse energy fluctuations inside the cavity. Using a self-referencing technique we have successfully stabilized this offset frequency, and thus the relative carrier-envelope phase, to an uncertainty as low as 10-5 radians in one second. Our experimental setup is a Kerr-lens mode-locked Ti:sapphire laser which generates an output pulse of roughly 15 fs with an average power of 300 mW.