Reciprocal passive mode locking of a rhodamine 6G dye laser and the Ar(+) pump laser

A rhodamine 6G dye laser, internally pumped within the extended cavity of an Ar(+)-ion laser, is mode locked when its cavity length is matched to half that of the pump laser: the 5145-A argon laser line is passively mode locked by the combination of the saturable absorption and the lasing action of the dye, which is in turn synchronously pumped and mode locked. Tunable (5650-5950-A) ~10 psec pulses are generated, and the average output power is ~80 mW.