Passive mode locking of a cw energy-transfer dye laser operating in the infrared near 800 nm.

The cw tuning range, and subsequent passive mode locking of a new argon-ion-pumped energy-transfer dye laser operating in the near IR, is reported for the first time to our knowledge. The gain medium, consisting of an energytransfer mixture of Pyridin 1 as the donor dye and Rhodamine 800 as the acceptor dye, has been found to lase continuous waves from 742 to 823 nm. Passively mode locked with bis-4-(1-ethylquinoline) [gamma-4'-(1'-ethylquino-line)] pentamethine cyanine diiodide dye, this active medium yielded sub-500-fsec pulses from 783 to 815 nm in a linear cavity, with pulses as short as 260 fsec being generated.