Efficient and tunable diode-pumped femtosecond Yb:glass lasers.

Diode-pumped Yb:phosphate and Yb:silicate glass lasers have been passively mode locked for the first time to the authors' knowledge. Reliable self-starting mode locking without critical cavity alignment has been achieved with intracavity semiconductor saturable-absorber mirrors and soliton mode locking. We generated pulses as short as 58 fs with the Yb:phosphate laser and 61 fs with the Yb:silicate laser at average output powers of 65 and 53 mW, respectively. The pulse repetition rate was 112 MHz. Additionally, we demonstrated tunability of femtosecond pulses from 1025 to 1065 nm for the Yb:phosphate and from 1030 to 1082 nm for the Yb:silicate glasses. The highest mode-locked output power was 405 mW, with 183-fs pulses from the phosphate glass. The diode pump power was 1.68 W, corresponding to 24% optical-to-optical efficiency. The highest cw output power was 510 mW at the same incident pump power.

Scaling of the antiresonant Fabry-Perot saturable absorber design toward a thin saturable absorber.

We demonstrate and discuss the scaling of the antiresonant Fabry-Perot saturable absorber toward a novel antiref lection-coated thin saturable absorber. With a Ti:sapphire laser we obtained self-starting Kerr-lens mode-locked pulses as short as 19 fs. With the higher modulation depth of the thin saturable absorber we obtained soliton mode-locked self-starting 34-fs pulses over the full cavity stability regime with a significantly shorter mode-locking buildup time. The pulse duration was limited only by the semiconductor Bragg mirror.

Experimental verification of soliton mode locking using only a slow saturable absorber.

We demonstrate experimentally that solid-state lasers with strong solitonlike pulse shaping can be mode locked by a slow saturable absorber only, i.e., the response time is much slower than the width of the soliton. A Ti:sapphire laser mode locked by a low-temperature-grown GaAs absorber with 10-ps recovery time generates pulses as short as 300 fs without the need for Kerr-lens mode locking and critical cavity alignment. An extrapolation of this result would predict that an asymptotically equal to 100-fs recovery time of a semiconductor absorber could support pulses into the 10-fs regime.

Diode-pumped 100-fs passively mode-locked Cr:LiSAF laser with an antiresonant Fabry-Perot saturable absorber.

We demonstrate a self-starting passively mode-locked diode-pumped Cr:LiSAF laser, achieving pulses as short as 98 fs with an average power as high as 50 mW. In continuous-wave operation, we demonstrate 140 mW of output power with a tunability of 100 nm FWHM. These results were achieved by use of lower Cr(3+) doping (1.5%), high-brightness diode lasers pumping from both sides of the crystal, and a low-loss antiresonant Fabry-Perot saturable absorber to start and sustain mode-locked operation.