Generation of 36-fsec pulses near 775 nm from a colliding-pulse passively mode-locked dye laser

We report the passive mode locking of a cw Rhodamine 700 dye laser using the saturable absorber DDI. Pulses as short as 36 fsec near 775 nm have been produced in intracavity group-velocity dispersion. The passively mode-locked cw dye laser has been proven to be a reliable source of ultrashort optical pulses. By combining the colliding-pulse mode-locked (CPM) technique ' and intracavity group-ve-locity dispersion (GVD) control, 2 pulses as short as 27 fsec (Ref. 3) and 19 fsec (Ref. 4) have been produced. Until recently, however, all the passively mode-locked systems have used the active-passive dye combination of Rhodamine 6G and DODCI, operating in the spec-tral region near 620 nm. In recent years several ac-tive-passive dye combinations have been studied, yielding subpicosecond pulses from 550 to 810 nm an