Kerr-lens mode locking with minimum nonlinearity using gain-matched output couplers

摘要

Broadband Kerr-lens mode locking is demonstrated at greatly reduced mode-locking strength with a gain-matchednoutput coupler that compensates for gain filtering. Already at very low pump powers, slightly above the cw lasingnthreshold, we are able to initiate robust mode locking and generate <8 fs output pulses from a Ti:sapphire laser withngood beam quality. Because dielectric coatings offer flexible design capabilities, this approach is applicable to variousnlasers with different gain media to extract pulses covering the full gain spectrum with minimum saturablenabsorber action.