Passively mode-locked diode-pumped surface-emitting semiconductor lasers

Summary form only given.We believe we demonstrate the first passively mode-locked surface-emitting semiconductor laser, using a semiconductor saturable absorber mirror (SESAM). We obtained 5-ps pulses with 15.3-mW average power and 2.5-GHz repetition rate or 12-ps pulses at 1.8 GHz with 40 mW. We anticipate that even multiwatt average powers should be achievable with our concept; more than 0.5 W has been demonstrated with a similar device in continuous wave operation. This potential arises from the fact that optically pumped semiconductor vertical-external-cavity surface-emitting lasers, in contrast to edge-emitting semiconductor lasers, allow one to scale up the mode area in order to generate a high average power and high pulse energy, while the external cavity enforces a diffraction-limited output. Multi-GHz repetition rates without Q-switching instabilities are possible. In addition, the broad amplification bandwidth should be sufficient for pulse durations in the subpicosecond regime.