We describe a mode-locked, diode-pumped Nd:YVO<sub>4</sub> laser with a very long optical cavity operating at 1064 nm. High-modulation, InGaAs quantum-well, semiconductor saturable-absorber mirrors were used for passive mode locking, providing a stable train of 13-ps pulses. A novel zero- q -transformation multipass cell provided a variable-length optical cavity as much as 100 m long. The output beam had <i>M</i><sup>2</sup><1.1 at average powers of 4.1, 3.9, and 3.5 W at repetition rates of 4.1, 2.6, and 1.5 MHz, respectively. To the best of our knowledge the last of these is the lowest repetition rate ever generated directly from a mode-locked nonfiber solid-state laser without cavity dumping.
© 2003 Optical Society of America
(140.3480) Lasers and laser optics : Lasers, diode-pumped
(140.3530) Lasers and laser optics : Lasers, neodymium
(140.3580) Lasers and laser optics : Lasers, solid-state
(140.4050) Lasers and laser optics : Mode-locked lasers
V. Z. Kolev, M. J. Lederer, B. Luther-Davies, and A. V. Rode, "Passive mode locking of a Nd: YVO 4 laser with an extra-long optical resonator," Opt. Lett. 28, 1275-1277 (2003)