Femtosecond transform-limited Kerr-lens mode-locked dye lasers

Using SF6 glass plates as intracavity Kerr lenses and double-prism pairs for dispersion compensation, we achieve tunable femtosecond passive mode locking in rhodamine 590 (R6G) and 4-dicyanomethylene-2-methyl-16-p-dimethylaminostyryl-4H-pyran (DCM) dye lasers. The R6G laser produces transform limited 240-500 fs pulses between 577 and 606 nm, and the DCM laser produces 150 fs transform-limited pulses between 650 and 671 nm. We use dilute intracavity saturable-absorber jets to make the mode locking self-starting. Characteristics of the pulses and the stability regions of the lasers agree with general theories of passive mode locking.