We report the first demonstration, to our knowledge, of soft-aperture Kerr-lens mode locking in a diode-pumped femtosecond Yb3+:YVO4 laser. Near-transform-limited pulses as short as 61 fs are generated around a center wavelength of 1050 nm with an output power of 54 mW and a pulse repetition frequency of 104.5 MHz. This is, to our knowledge, the shortest pulse generated directly from an Yb laser having a crystalline host material. The femtosecond operation has a mode-locking threshold at an absorbed pump power of 190 mW. The nonlinear refractive indexes of the Yb3+:YVO4 crystal have been measured to be 19×10<sup>−16</sup> cm<sup>2</sup>/W and 15×10<sup>−16</sup> cm<sup>2</sup>/W for the σ and π polarizations, respectively, at 1080 nm.
© 2005 Optical Society of America
(140.3480) Lasers and laser optics : Lasers, diode-pumped
(140.3580) Lasers and laser optics : Lasers, solid-state
(140.4050) Lasers and laser optics : Mode-locked lasers
(140.5680) Lasers and laser optics : Rare earth and transition metal solid-state lasers
(140.7090) Lasers and laser optics : Ultrafast lasers
A. A. Lagatsky, A. R. Sarmani, C. T. A. Brown, W. Sibbett, V. E. Kisel, A. G. Selivanov, I. A. Denisov, A. E. Troshin, K. V. Yumashev, N. V. Kuleshov, V. N. Matrosov, T. A. Matrosova, and M. I. Kupchenko, "Yb3+-doped YVO4 crystal for efficient Kerr-lens mode locking in solid-state lasers," Opt. Lett. 30, 3234-3236 (2005)