Published online by Cambridge University Press: 15 November 2002
Femtosecond modelocked lasers using new ytterbium-doped borate crystals (Yb:Sr3Y(BO3)3, Yb:Ca4GdO(BO3)3 and Yb:Ca4YO(BO3)3) are demonstrated. Pulse duration as short as 69 fs has been obtained. To modelock such lasers, fast saturable absorbers need to be used. Two different types of fast saturable absorbers have been studied: low-temperature-grown semiconductor mirrors (SESAM) and high-energy-ion-implanted semiconductor Bragg reflectors (SBR). We demonstrated, for the first time to our knowledge, that ion-implanted SBR can be used to modelock oscillators using Yb-doped materials.