Passive mode locking using an antiresonant-ring laser cavity

Substantial improvement in passive laser mode locking has recently been demonstrated by employing two colliding pulses in an intracavity saturable absorber cell. Experiments to date have used either a double-pulse standing-wave cavity or a two-way ring laser cavity. The special properties of the antiresonant-ring laser cavity should provide another simple and useful way to obtain two colliding pulses inside a single-pulse and single-output standing-wave cavity.