Femtosecond synchronization of two passively mode-locked Ti:sapphire lasers

We describe a method of reducing the timing jitter between two passively mode-locked femtosecond titanium:sapphire laser systems, enabling femtosecond-resolved measurements with independently tunable pump and probe wavelengths. The scheme supplements a commercially available system (Coherent Synchrolock) which locks two Ti:sapphire lasers to a master clock. By selecting only those pulses which are temporally coincident within a user-specified range, a timing jitter reduction between the two lasers from ∼3 ps to <200 fs FWHM can be achieved, as measured by optical cross correlation. The timing jitter between the lasers is easily varied, allowing optimization of the tradeoff between temporal resolution and throughput depending on experimental needs.