Single-walled carbon-nanotube saturable absorber assisted Kerr-lens mode-locked Tm:MgWO₄ laser

Abstract

We demonstrate sub-100-fs Kerr-lens mode-locking of a T m : M g W O 4 laser emitting at ∼ 2 µ m assisted by a single-walled carbon-nanotube saturable absorber. A maximum average output power of 100 mW is achieved with pulse duration of 89 fs at a pulse repetition rate of ∼ 86 M H z . The shortest pulse duration derived from frequency-resolved optical gating amounts to 76 fs at 2037 nm, corresponding to nearly bandwidth-limited pulses. To the best of our knowledge, these are the shortest pulses generated from any Tm-doped tungstate crystal and the first report on saturable absorber assisted Kerr-lens mode-locking of a Tm laser at ∼ 2 µ m .